JP2010272997A - Receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately remove various kinds of noise generated in a vehicle from the reception signal of a signal wave. <P>SOLUTION: The signal wave and the noise (in-vehicle noise) are received by an antenna 11, and tuner signal processing and FFT are performed in the reception signal of the antenna 11, so as to obtain an object signal on a frequency axis. Only the noise is received by an antenna 21, and the tuner signal processing and FFT are performed in the reception signal of the antenna 21, so as to obtain a reference signal on the frequency axis. The phase and amplitude of the reference signal is adjusted by each frequency component, and the adjusted reference signal is added to the object signal by each frequency component, so that the noise components in the object signal are removed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a receiving apparatus such as a digital broadcast receiving apparatus that receives a signal wave to be transmitted in terrestrial digital broadcasting or digital wireless communication.

  In recent years, in-vehicle mobile communication that performs terrestrial digital broadcast reception, wireless LAN (Local Area Network) communication, and the like on a vehicle has been actively used. When receiving weak radio waves in in-vehicle mobile communication, various noises generated in the vehicle affect the reception characteristics. Noise generated in the vehicle includes noise from a vehicle engine and noise from various electronic control devices, and also includes noise from an inverter in an electric vehicle and a hybrid vehicle. Since these noises adversely affect reception characteristics, a technique for removing the noises is required.

  Generally, when reducing acoustic noise such as noise, a microphone that receives noise is provided separately, and the inverted noise that is the phase of the received noise from the microphone is added to the signal wave, and the inverted noise is added. A noise removal method is known in which the received signal wave and ambient noise are received together to cancel and reduce the noise. Such a noise removal method is applied to music headphones and the like. This method is based on the premise that the phase of the noise received by the microphone is the same as the phase of the ambient noise directly received.

  Moreover, although it is not a noise reduction method with respect to the vehicle-mounted digital broadcast receiver, the following noise reduction method is proposed in the radio | wireless apparatus (refer the following patent document 1). That is, the first antenna for receiving the noise of the own device and the second antenna for receiving the noise and the external signal including the signal wave are provided in the wireless device, and the noise of the own device is generated. In the state where no external signal is received, noise is received by the first and second antennas, and the difference between the first and second baseband signals based on the reception noise of the first and second antennas is stored. In a normal operation in which an external signal is received, noise is reduced by subtracting the difference from the received signal of the external signal.

JP 2004-304670 A

  It is also possible to apply such a conventional method to a vehicle-mounted digital broadcast receiver. However, since there are many noise sources as described above in the vehicle, and the distance between the noise source and the antenna and the frequency of the noise differ depending on the noise source, the phase of the noise received by the first and second antennas is Different for each noise source. Therefore, if all noises are uniformly subtracted from the received signal of the signal wave as in the conventional method described above, all noises having different phases and frequencies cannot be effectively removed. Furthermore, the conventional method is considered to be difficult to cope with noise that occurs discontinuously in time, such as noise caused by spark of an engine spark plug.

  Accordingly, an object of the present invention is to provide a receiving apparatus having a function of effectively reducing various noises.

  A receiving apparatus according to the present invention is a receiving apparatus attached to an object having a noise source, a first antenna that receives a signal wave and noise from the noise source, and a time axis based on a received signal of the first antenna. A first tuner for outputting the above digital signal; a first converter for converting the output signal of the first tuner to a first signal on the frequency axis, which is composed of a plurality of discretized frequency components; A second antenna that receives the noise, a second tuner that outputs a digital signal on a time axis based on a reception signal of the second antenna, and an output signal of the second tuner that is derived from the plurality of frequency components A second conversion unit for converting the second signal on the frequency axis, a phase amplitude adjustment unit for adjusting the phase and amplitude of the second signal for each frequency component, and the first for each frequency component. Front with signal An adder for adding the second signal subjected to adjustment, and further comprising a.

  Since the phase and amplitude of the second signal with respect to noise are adjusted for each frequency component and then the second signal is added to the first signal, various noises with different distances and frequencies between the noise source and the antenna are effectively removed. It becomes possible to reduce.

  Specifically, for example, the phase amplitude adjustment unit performs the adjustment based on phase amplitude information that defines a phase and amplitude adjustment amount for each frequency component, and the phase amplitude according to the addition result of the addition unit Update information.

  Thereby, adjustment according to an actual reception situation is possible.

  Further, for example, the receiving apparatus operates in any one of a plurality of operation modes including a first mode and a second mode, and in the second mode, the phase difference and the amplitude ratio of the first signal and the second signal are set to the A setting storage unit that sets and stores the phase amplitude information by obtaining each frequency component is further provided in the receiving device, and in the first mode, the phase amplitude adjustment unit stores the stored phase amplitude information. To make the adjustment.

  In the first mode, if the adjustment is performed using the stored phase amplitude information in a fixed manner, the processing speed in the first mode can be increased. However, it is also possible to update the information based on the phase amplitude information set in the setting storage unit.

  Specifically, for example, in the first mode, the first and second antennas, the first and second tuner units, the first and second conversion units, the phase amplitude adjustment unit, and the addition unit are used. A baseband signal of the signal wave is obtained from the adding unit, and in the second mode, the phase amplitude information is set and stored under a specific reception environment, and the first antenna in the second mode is set by the first antenna. The specific reception environment is adjusted so that the reception intensity of the signal wave is smaller than that in the first mode.

  More specifically, for example, the object is a vehicle, and the receiving device is a digital broadcast receiving device that receives a broadcast wave as the signal wave.

  For example, the second antenna may be installed in a space surrounded by a metal part that forms the vehicle body of the vehicle.

  In order to appropriately obtain the noise reduction effect by the addition by the adding unit, it is necessary to suppress the reception of the signal wave by the second antenna as much as possible. If comprised as mentioned above, it will become unnecessary to prepare the special apparatus for obtaining a signal wave shielding effect separately.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the receiver provided with the function to reduce various noises effectively.

  The significance or effect of the present invention will become more apparent from the following description of embodiments. However, the following embodiment is merely one embodiment of the present invention, and the meaning of the term of the present invention or each constituent element is not limited to that described in the following embodiment. .

It is a schematic block diagram of the receiver which concerns on 1st Embodiment of this invention. It is a figure which shows the installation state to the vehicle of the antenna in the receiver of FIG. It is a figure for demonstrating the principle of the noise reduction process which concerns on this invention. It is an internal block diagram of the equalization process part and phase amplitude adjustment part which concern on 1st Embodiment of this invention. It is a figure for demonstrating the phase and amplitude adjustment method which concerns on 1st Embodiment of this invention, Comprising: It is a figure which shows the signal point of the ideal received signal on an IQ plane at the time of using QPSK. is there. It is a figure for demonstrating the phase and amplitude adjustment method which concerns on 1st Embodiment of this invention, Comprising: The figure which shows a mode that the signal point of an actual received signal is moved and corrected toward the signal point of an ideal received signal It is. It is a figure which concerns on 2nd Embodiment of this invention and shows the arrangement | sequence of SP signal (scattered pilot signal) and a data signal in an OFDM symbol sequence. It is an internal block diagram of the equalization process part and phase amplitude adjustment part which concern on 2nd Embodiment of this invention. It is a flowchart showing the operation | movement procedure of the receiver which concerns on 2nd Embodiment of this invention. It is a figure for demonstrating the derivation method of the phase amplitude information with respect to one noise source concerning 3rd Embodiment of this invention. It is a partial block diagram of the receiver which concerns on 3rd Embodiment of this invention. It is a figure for demonstrating the derivation method of the phase amplitude information which concerns on 3rd Embodiment of this invention, Comprising: It is a figure which shows the receiving condition of the some noise by two antennas.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. In each of the drawings to be referred to, the same part is denoted by the same reference numeral, and redundant description regarding the same part is omitted in principle.

<< First Embodiment >>
A first embodiment of the present invention will be described. FIG. 1 shows a schematic block diagram of a receiving apparatus 1 according to the first embodiment of the present invention. The receiving device 1 is provided with each part referred by the codes | symbols 11-15 and 21-24.

  The receiving apparatus 1 has a receiving system using the antenna 11 as a signal input source and a receiving system using the antenna 21 as a signal input source. The receiving device 1 is installed in a vehicle such as an automobile. FIG. 2 shows a state where the antennas 11 and 21 are installed in the vehicle 2 as an automobile. So that signal waves, external noise, and noise generated in the vehicle 2 due to digital broadcasting, data communication, etc. are received by the antenna 11, and only noise generated in the vehicle 2 is received by the antenna 21. The antennas 11 and 21 are installed in the vehicle 2. The external noise refers to noise other than noise generated in the vehicle 2.

  Specifically, for example, as shown in FIG. 2, the antenna 11 is installed on the windshield of the vehicle 2, and the antenna 21 is a specific space having a signal wave shielding effect so that the signal wave is not received by the antenna 21. Installed inside. The specific space may be formed by a metal member (body, frame, chassis, etc.) that forms the vehicle 2. That is, a three-dimensional space surrounded by metal members forming the vehicle 2 may be used as the specific space. The arrival of the signal wave to the antenna 21 is suppressed by the metal member. Specifically, for example, the antenna 21 may be installed in the engine room of the vehicle 2, below the driver's seat, and below the seat other than the driver's seat. FIG. 2 shows a state where the antenna 21 is installed in the engine room of the vehicle 2.

  However, the specific space can be formed by separately using a metal member other than the metal member forming the vehicle 2. Further, it is not always necessary that the entire outer peripheral surface of the specific space is covered with a metal member. The signal wave shielding effect is not perfect. Actually, a signal wave having a certain level of signal strength is received by the antenna 21, but the reception strength of the signal wave by the antenna 21 is sufficiently smaller than that of the antenna 11. Therefore, it is assumed that no signal wave is received by the antenna 21.

  The components of the receiving device 1 other than the antennas 11 and 21 are installed near the driver's seat of the vehicle 2, for example. Hereinafter, unless otherwise specified, noise refers to noise generated by the vehicle 2 (hereinafter also referred to as in-vehicle noise), and a signal wave refers to a signal that includes external noise (that is, a signal wave is a true signal wave). This is a signal wave with extraneous noise added). In general, there are a plurality of noise sources for in-vehicle noise, the distance between the antenna and the noise source differs between the antennas 11 and 21, and the noise frequency differs between the different noise sources. Further, in the following description, for the sake of concrete description, it is assumed that a signal wave by digital broadcasting modulated by OFDM (Orthogonal Frequency Division Multiplexing) is received by the antenna 11. In this case, it can be said that the receiving device 1 is a digital broadcast receiving device.

  The receiving apparatus 1 and a transmitting station (digital broadcast transmitting apparatus) (not shown) constitute a digital broadcast system, which employs the OFDM system as a broadcast system. The OFDM scheme is a scheme for multiplexing and transmitting a large number of subcarriers (hereinafter also simply referred to as carriers) orthogonal to each other within a band of one channel.

  At the transmitting station, the baseband signal to be transmitted is modulated for each subcarrier by a modulation scheme such as QAM (Quadrature Amplitude Modulation), QPSK (Quadrature Phase Shift Keying), and DQPSK (Differential Quadrature Phase Shift Keying). An OFDM signal is generated by subjecting the obtained signal to inverse fast Fourier transform (IFFT). The baseband signal includes a video signal and an audio signal to be transmitted. The generated OFDM signals for a plurality of channels are transmitted from the transmitting station as signal waves to be transmitted to the receiving device 1 by digital broadcasting (for example, so-called terrestrial digital broadcasting).

  The antenna 11 receives a signal wave transmitted by this digital broadcast. The reception signal of the antenna 11 is output to the tuner unit 12 as an RF signal (high frequency signal). In the tuner unit 12, tuner signal processing including amplification, channel selection, frequency conversion, and the like is performed on the RF signal from the antenna 11. By the tuner signal processing, an IF signal (intermediate frequency signal) is generated from the RF signal from the antenna 11. ) Is generated. An IF signal based on the RF signal of the antenna 11 is converted into a digital signal by an AD converter (not shown) included in the tuner unit 12 and sent to the FFT processing unit 13. The digital signal output from the tuner unit 12 to the FFT processing unit 13 is a signal on the time axis.

  The FFT processing unit 13 converts a signal on the time axis sent from the tuner unit 12 into a signal on the frequency axis using a fast Fourier transform (hereinafter referred to as FFT). A signal on the frequency axis obtained by the conversion in the FFT processing unit 13 is hereinafter referred to as a target signal. The target signal is sent to the noise removal / equalization processing unit 14 (hereinafter abbreviated as the equalization processing unit 14).

  The equalization processing unit 14 performs equalization processing to remove distortion from the target signal. This distortion is mainly caused by multipath on the transmission path. Further, the equalization processing unit 14 also performs noise reduction processing for reducing noise included in the target signal. Although details will be described later, the noise reduction processing is realized in cooperation with the phase amplitude adjustment unit 24. The target signal after the equalization process and the noise reduction process is sent to the demodulation processing unit 15 as an output signal of the equalization processing unit 14. In this specification, the expression of reduction or removal is used for noise, but both are synonymous. The expression “removing noise” means removing part or all of the noise, and if part or all of the noise is removed from a signal, the noise in the signal is reduced.

  The demodulation processing unit 15 performs demodulation processing for converting the output signal of the equalization processing unit 14 into a baseband signal. For example, in the demodulation process, the output signal of the equalization processing unit 14 is converted into an MPEG (Moving Picture Experts Group) encoded signal as a baseband signal. The MPEG encoded signal is a signal obtained by encoding a video signal or an audio signal to be transmitted by digital broadcasting. The MPEG encoded signal obtained by this demodulation processing is sent to an MPEG decoder (not shown), decoded, then sent to a display device or a speaker (both not shown), and displayed as video or output as audio. . The receiving device 1 can also include an MPEG decoder, a display device, and a speaker.

  As described above, the antenna 21 receives only noise (receives only a noise signal representing noise). A reception signal of the antenna 21 is output to the tuner unit 22 as an RF signal. In the tuner unit 22, tuner signal processing including amplification, channel selection, frequency conversion, and the like is performed on the RF signal from the antenna 21, and an IF signal is generated from the RF signal from the antenna 21 by the tuner signal processing. . An IF signal based on the RF signal of the antenna 21 is converted into a digital signal by an AD converter (not shown) included in the tuner unit 22 and sent to the FFT processing unit 23. The digital signal output from the tuner unit 22 to the FFT processing unit 23 is a signal on the time axis.

  The FFT processing unit 23 converts the signal on the time axis sent from the tuner unit 22 into a signal on the frequency axis using FFT. The signal on the frequency axis obtained by the conversion in the FFT processing unit 23 is hereinafter referred to as a reference signal. The reference signal is sent to the phase amplitude adjustment unit 24.

  The first receiving system formed including the antenna 11, the tuner unit 12 and the FFT processing unit 13 and the second receiving system formed including the antenna 21, the tuner unit 22 and the FFT processing unit 23 are synchronized. The reception operation is performed using the same reception parameter at the same timing. The reception parameters here include the amplification degree in tuner signal processing, the band of the selected channel, the condition for frequency conversion, the FFT condition, and the like. That is, the content of the process of generating the target signal from the received signal of the antenna 11 is the same as the content of the process of generating the reference signal from the received signal of the antenna 21, and the former, the process, and the latter process are executed at the same timing. The

  The phase and amplitude of the reference signal is adjusted by the phase / amplitude adjustment unit 24, and the noise reduction processing is realized by adding the adjusted reference signal to the target signal in the equalization processing unit 14.

  The principle of noise reduction processing will be described with reference to FIG. FIG. 3 is a schematic block diagram of a part responsible for noise reduction processing. 3, reference numeral 24a represents a phase amplitude adjustment unit that can be used as the phase amplitude adjustment unit 24 in FIG. 1, and reference numeral 101 represents an addition unit that can be provided in the equalization processing unit 14 in FIG. A phase amplitude calculation unit 102 is provided in the phase amplitude adjustment unit 24a.

  Since the target signal is a signal on the frequency axis obtained by FFT, it consists of M frequency components discretized. M is an integer of 2 or more. The same applies to the reference signal. The M frequency components forming the target signal or the reference signal are composed of the first to Mth frequency components, and the frequency of the (j + 1) th frequency component is higher than the frequency of the jth frequency component (j Is an integer). In order to distinguish the frequency of each frequency component forming the target signal or the reference signal from other frequencies, the former frequency is also referred to as a discretized frequency, and the discretized frequency of the jth frequency component is defined as jth frequency component. Is called the discretization frequency. Also, assume that M matches the number of carriers in OFDM modulation.

  A signal representing a signal wave included in the target signal is represented by S, and a signal representing noise contained in the target signal is represented by N1. Then, the target signal is the sum (S + N1) of the signal wave S and the noise N1. On the other hand, the reference signal is represented by N2. N2 is a signal representing noise as a reference signal. As described above, the difference between the phase and amplitude of the noise received by the antenna 11 and the phase and amplitude of the noise received by the antenna 21 depends on the distance between the noise source and the antennas 11 and 21 and the frequency of the noise. Dependent.

  Considering this, the phase amplitude calculation unit 102 uses the phase amplitude information set for each frequency component (that is, set for each discretized frequency) so that the difference is canceled for each frequency component. The signal (−N2 ′) is generated by adjusting the phase and amplitude of the reference signal N2. The signal (−N2 ′) is obtained by performing the adjustment on the reference signal N2. Then, the adder 101 adds the signal (−N2 ′) to the target signal (S + N1) to obtain a signal (S + N1−N2 ′). Since (N1−N2 ′) is substantially zero in the signal (S + N1−N2 ′), noise is reduced by this addition.

  In an ordinary automobile, an engine or inverter (DC-AC inverter) mounted on the automobile functions as a noise source. When the noise reduction processing according to the present invention is not performed, the CN ratio (Carrier to Noise Ratio) deteriorates due to these noise sources. The degree of this deterioration depends on the installation position of the antenna. For example, when the antenna is attached to the windshield, the CN ratio is deteriorated by about 2 to 4 dB when the engine is started, and the CN ratio is deteriorated by 1 to 3 when the inverter is started. It is about 2 dB. These deteriorations are reduced by the noise reduction processing according to the present invention.

  An internal configuration example of the equalization processing unit 14 and the phase amplitude adjustment unit 24 based on the above principle will be described. FIG. 4 is an internal block diagram of the equalization processing unit 14 b and the phase amplitude adjustment unit 24 b that can be used as the equalization processing unit 14 and the phase amplitude adjustment unit 24. The equalization processing unit 14b is provided with an addition unit 111 and an equalization unit 112, and the phase amplitude adjustment unit 24b is provided with a phase amplitude calculation unit 113 and a MER calculation unit 114.

  The adder 111 adds the signal (−N2 ′) sent from the phase amplitude calculator 113 to the target signal (S + N1) for each frequency component (in other words, for each discretized frequency). The included noise is reduced, and (S + N1-N2 ′), which is the target signal after noise reduction, is output. The equalization unit 112 performs equalization processing to remove distortion included in the output signal (S + N1-N2 ′) of the addition unit 111, and the equalized signal (S + N1-N2 ′) is converted into the signal (S '+ N1'-N2' '). Any equalization process including a known equalization process can be used as the equalization process in the equalization unit 112 (the same applies to other equalization units described later (for example, the equalization unit 133 in FIG. 8)). . The output signal (S ′ + N1′−N2 ″) of the equalization unit 112 can be sent to the demodulation processing unit 15 in FIG. 1 as the output signal of the equalization processing unit 14b.

  In order to realize noise reduction, it is necessary to adjust the phase and amplitude of the reception noise of the antenna 21 by some phase amplitude information. In the example shown in FIG. 4, the MER calculation unit 114 is used to obtain this phase amplitude information. Use.

  The MER calculation unit 114 calculates a MER (Modulation Error Ratio) indicating the reception state of the signal wave based on the output signal (S ′ + N1′−N2 ″) of the equalization unit 112. As is well known, the better the signal wave reception state, that is, the smaller the noise contained in the output signal (S ′ + N1′−N2 ″) of the equalization unit 112, the greater the MER. MER is defined by the following formula (1).

Here, I _j and Q _j are an I element and a Q element in the j-th frequency component of the received signal to be MER calculated, respectively, and I _Ij and Q _Ij are ideal without noise, respectively. These are the I element and Q element in the j-th frequency component of the received signal. The subscript “j” in I _j , Q _j , I _Ij and Q _Ij represents the frequency component number. M is the number of carriers in OFDM modulation as described above. In a digital broadcasting system using orthogonality such as OFDM modulation, a received signal can be decomposed into an in-phase component and a quadrature component. The I element refers to the in-phase component, and the Q element refers to the quadrature component. As is well known, the phase and amplitude of a signal is defined by the I and Q elements of the signal.

With respect to the equalized signal (S ′ + N1′−N2 ″), the I elements in the jth frequency component of the signals S ′, N1 ′, and N2 ″ are IS _j , IN1 _j, and IN2 _j , respectively. In addition, Q elements in the j-th frequency component of the signals S ′, N1 ′, and N2 ″ are represented by QS _j , QN1 _j, and QN2 _j, respectively. When the signal (S ′ + N1′−N2 ″) is regarded as a MER calculation target, I _j and Q _j are expressed by the following equations (2A) and (2B). Substituting these equations (2A) and (2B) into the above equation (1) yields equation (3).

Since the MER increases as the noise included in the output signal (S ′ + N1′−N2 ″) of the equalization unit 112 decreases, the I element I _j and the Q element of the output signal (S ′ + N1′−N2 ″) Q _j is the noise by obtaining a signal by adjusting the phase and amplitude of the reference signal N2 so as to approach the I component I _Ij and Q components Q _Ij of ideal reception signal (-N @ 2 ') is reduced . Information defining the amount of phase and amplitude adjustment for obtaining the signal (−N2 ′) from the reference signal N2 is phase amplitude information. As described above, since the phase and amplitude are adjusted for each frequency component, the phase amplitude information is determined for each frequency component (in other words, determined for each discrete frequency). That is, phase amplitude information is individually determined for each of the first to Mth frequency components, and the phase and amplitude of the reference signal N2 are adjusted for each frequency component using the phase amplitude information for each frequency component.

In the phase amplitude adjustment unit 24b (for example, the phase amplitude calculation unit 113), phase amplitude information for each frequency component can be stored as an adjustment parameter. An adjustment parameter for the j-th frequency component is represented by α _j . The adjustment parameter α _j is updated according to the output signal (S ′ + N1′−N2 ″) of the equalization unit 112.

Specifically, the adjustment parameter α _j as phase amplitude information may be acquired as follows. As described above, the I element and the Q element in the jth frequency component in the output signal (S ′ + N1′−N2 ″) of the equalization unit 112 are regarded as I _j and Q _j . On the other hand, I _Ij and Q _Ij are known to the receiving apparatus 1. Therefore, the MER can be calculated by the above equation (1) from the I and Q elements of each frequency component of the output signal (S ′ + N1′−N2 ″) and the known information representing I _Ij and Q _Ij. .

For example, when QPSK is used as a baseband signal modulation scheme in a transmitting station, signal points (I _Ij , Q _Ij ) on the _IQ plane are signal points (I _A , Q _A ), ( I _B , Q _B ), (I _C , Q _C ), and (I _D , Q _D ). The IQ plane is a plane whose coordinate axes are the I axis corresponding to the amount of the I element and the Q axis corresponding to the amount of the Q element, and the signal point (I _X , Q _X ) It represents a point on the IQ plane of a signal whose elements are I _X and Q _X , respectively. The signal points (I _A , Q _A ), (I _B , Q _B ), (I _C , Q _C ) and (I _D , Q _D ) are respectively the first, second and third of the IQ plane. And in the fourth quadrant, | I _A | = | I _B | = | I _C | = | I _D | and | Q _A | = | Q _B | = | Q _C | = | Q _D | is there.

  For the sake of concrete explanation, a case is assumed in which QPSK is used as a baseband signal modulation scheme in a transmitting station.

  The antenna 11 successively receives signal waves of the first, second, third,... Symbols that are sequentially transmitted. First, the antenna 11 receives the signal wave and noise of the first symbol as a signal wave for one symbol, generates a first target signal (S + N1) from the received signal, and simultaneously Noise is received by the antenna 21, and a first reference signal N2 is generated from the received signal.

Phase amplitude calculating unit 113 checks the amplitude of the first reference signal N2 is equal to or more than a predetermined reference amplitude TH _AMP for each of the frequency components of the first to M, the frequency component of the j If the amplitude of the first reference signal N2 is equal to or greater than the reference amplitude TH _AMP , the jth frequency of the first reference signal N2 is increased in the direction in which the MER increases (for example, the MER becomes maximum). The phase and amplitude of the component are adjusted, and an adjustment parameter α _j for realizing the adjustment is stored.

Specifically, for example, a signal (−N2 ′) is generated from the first reference signal N2 using an initial parameter (initial value of the adjustment parameter α _j ) set in advance for each frequency component, and added. Through the unit 111 and the equalization unit 112, the output signal (S ′ + N1′−N2 ″) [1] of the equalization unit 112 based on the first target signal, the reference signal, and the initial parameters is generated. In the signal (S ′ + N1′−N2 ″) [1], an I element and a Q element in the j-th frequency component are set as I _j [1] and Q _j [1], respectively. Note that an initial parameter as an initial value of the adjustment parameter α _j can be set according to a method described in a third embodiment to be described later.

In the first frequency component consider the case where the amplitude of the first reference signal N2 is the reference amplitude TH _AMP or more. In this case, the signal point on the I-Q plane _{(I 1 [1], Q} 1 [1]) is I ₁ so as to move toward the signal point _{(I I1, Q I1) [} 1] and Q ₁ [ 1] is corrected. The corrected I ₁ [1] and Q ₁ [1] are set as I ₁ [1] ′ and Q ₁ [1] ′, respectively. In this modification, if the signal point (I ₁ [1], Q ₁ [1]) is located in the first, second, third, and fourth quadrants on the IQ plane, It can be assumed that the point (I _I1 , Q _I1 ) is the signal point (I _A , Q _A ), (I _B , Q _B ), (I _C , Q _C ), (I _D , Q _D ). .

Therefore, for example, as shown in FIG. 6, when the signal point (I ₁ [1], Q ₁ [1]) is located in the first quadrant of the IQ plane, the signal point ( The distance between the signal point (I _A , Q _A ) as I _I1 , Q _I1 ) and the corrected signal point (I ₁ [1] ′, Q ₁ [1] ′) is a predetermined reference distance TH _D The position of the signal point is corrected so that A broken-line circle 301 in FIG. 6 is a circle having the signal point (I _A , Q _A ) as the center and the reference distance TH _D as the radius. If the amplitude of the first reference signal N2 is greater than or equal to the reference amplitude TH _AMP in the first frequency component, the signal point (I ₁ [1], Q ₁ [1]) is located outside the dashed circle 301 ( The same applies to the second to Mth frequency components). Ultimately, TH _D → 0, so that the MER is maximized (see the above formula (1)).

The phase amplitude calculation unit 113 corrects the signal point (I ₁ [1], Q ₁ [1]) to the signal point (I ₁ [1] ′, Q ₁ [1] ′). And the phase amplitude information representing the adjustment amount is stored as the adjustment parameter α ₁ . Although the case where the amplitude of the first reference signal N2 in the first frequency component is equal to or _larger than the reference amplitude TH _AMP is considered, the first reference signal N2 in the jth frequency component other than the first frequency component is considered. Similar processing is performed when the amplitude is equal to or greater than the reference amplitude TH _AMP , and the adjustment parameter α _j is derived and stored. When the amplitude of the first reference signal N2 in the j-th frequency component is less than the reference amplitude TH _AMP , the initial parameter for the j-th frequency component may be stored as it is as the adjustment parameter α _j. it can.

Next, the signal wave and noise of the second symbol are received by the antenna 11, the second target signal (S + N1) is generated from the received signal, and the noise is simultaneously received by the antenna 21. Thus, the second reference signal N2 is generated from the received signal. The phase amplitude calculation unit 113 adjusts the phase and amplitude of the second reference signal N2 for each frequency component using the adjustment parameter α _j stored at that time, and generates a signal (−N2 ′). . The adder 111 and the equalizer 112 equalize the second symbol from the signal (−N2 ′) generated from the second reference signal N2 and the second target signal (S + N1). The output signal (S ′ + N1′−N2 ″) [2] of the unit 112 is obtained. In the signal (S ′ + N1′−N2 ″) [2], the I and Q elements in the j-th frequency component are set as I _j [2] and Q _j [2], respectively.

On the other hand, the phase amplitude calculation unit 113 checks whether or not the amplitude of the second reference signal N2 is greater than or equal to the reference amplitude TH _AMP for each of the first to Mth frequency components, and the jth frequency. If the amplitude of the second reference signal N2 in the component is greater than or equal to the reference amplitude TH _AMP , the adjustment parameter α _j is updated in a direction in which the MER increases (for example, the MER is maximized).

At this time, for example, if the amplitude of the second reference signal N2 is equal to or greater than the reference amplitude TH _AMP in the first frequency component, the signal point (I ₁ [2], Q ₁ [2]) is changed to the signal point ( I ₁ [2] ′, Q ₁ [2] ′), assuming that the phase and amplitude adjustment amount necessary for the correction is obtained, and temporarily adjusting the phase amplitude information representing the adjustment amount Is obtained as a parameter α ₁ The signal point (I ₁ [2] ′, Q ₁ [2] ′) is the signal point (I ₁ [2], Q ₁ [2]) on the IQ plane. I _I1 , Q _I1 ) and the distance between the signal point (I _I1 , Q _I1 ) and the signal point (I ₁ [2] ′, Q ₁ [2] ′) a reference distance TH _D. Then, an average of the adjustment parameter alpha ₁ stored the tentatively determined adjustment parameter alpha ₁ and at present has to be updated stored as the latest adjustment parameter alpha _1. The same applies to frequency components other than the first frequency component.

By repeatedly performing the update storage process of the adjustment parameter α _j as described above each time a new symbol is received, the adjustment parameter α _j converges to an optimal parameter according to the noise reception state. As a result, good noise reduction is realized.

  According to the present embodiment, various noises having different frequencies and phases can be effectively removed from the received signal including the signal wave. Further, if a specific space having a signal wave shielding effect is formed by using a metal member forming the vehicle 2 and the antenna 21 is disposed in the specific space, a special space for obtaining the signal wave shielding effect is obtained. It is no longer necessary to prepare a separate device, and only in-vehicle noise can be received by the antenna 21 at low cost and effectively.

<< Second Embodiment >>
A second embodiment of the present invention will be described. The second embodiment is an embodiment obtained by modifying a part of the first embodiment. Regarding matters not specifically described in the second embodiment, the matters described in the first embodiment are the same as those in the second embodiment as long as there is no contradiction. Also applies. The same applies to a third embodiment described later. In the second embodiment, in-vehicle noise included in a scattered pilot signal (hereinafter referred to as SP signal) of a signal wave of digital broadcasting and in-vehicle noise included in a data signal are separately obtained before and after equalization processing. Remove.

  First, the SP signal and data signal in the signal wave will be described. As broadcasting systems for digital broadcasting, there are Japanese ISDB-T (Integrated Services Digital Broadcasting-Terrestrial) system and European DVB-T (Digital Video Broadcasting-Terrestrial) system. An SP signal with a known phase is inserted. For example, in the Japanese ISDB-T system, SP signals are arranged as shown in FIG. Hereinafter, for concrete explanation, a case where a signal wave of digital broadcasting according to the Japanese ISDB-T system is received by the antenna 11 will be described.

  The target signal output from the FFT processing unit 13 in FIG. 1 is obtained by adding a signal about noise to an OFDM signal which is a signal about a signal wave. As shown in FIG. 7, the OFDM signal is composed of a data signal and an SP signal arranged in the frequency direction and the time direction, which are collectively referred to as an OFDM symbol string.

  A time number (symbol number) corresponding to the time direction is represented by t, and a frequency number corresponding to the frequency direction is represented by l. Here, t takes an integer of 0 or more. One frequency component (and one discretized frequency) corresponds to one frequency number. As the frequency number l increases, the corresponding frequency increases. As described in the first embodiment, since the number of carriers in OFDM modulation is M, l is an integer of 0 or more and (M−1) or less. t represents a time considered with the symbol length of the OFDM signal as a unit. A position in the OFDM symbol string that is uniquely determined by uniquely defining t and l is called a carrier position, and is represented by (t, l).

  The SP signal is arranged at a carrier position that satisfies l = 3 × (t mod 4) + 12p. Here, mod represents a remainder operation, and p is an integer. That is, as shown in FIG. 7, in the OFDM signal at a certain time t, the SP signal is arranged on every 12 carriers on the frequency axis, and as the time t advances by 1, the SP signal is shifted by 3 carriers in the frequency direction. Shifted. For example, at time t = 0, SP signals are arranged at carrier positions (0, 0), (0, 12), (0, 24), (0, 36), etc., and at time t = 1, SP signals are arranged at carrier positions (1, 3), (1, 15), (1, 27), (1, 39),. The carrier position where the SP signal is arranged is also called an SP position, and the carrier position where the data signal is arranged is also called a data position.

  In the OFDM symbol sequence, a data signal is arranged in a portion where no SP signal is arranged. The data signal includes original information to be transmitted from the transmitting station to the receiving apparatus 1, and an MPEG encoded signal is generated from this data signal.

  FIG. 8 is an internal block diagram of the equalization processing unit 14 c and the phase amplitude adjustment unit 24 c that can be used as the equalization processing unit 14 and the phase amplitude adjustment unit 24. Each part referred to by reference numerals 131 to 134 is provided in the equalization processing unit 14c, and each part referred to by reference numerals 141 to 144 is provided in the phase amplitude adjustment unit 24c. In the second embodiment, operations of the equalization processing unit 14c and the phase amplitude adjustment unit 24c will be described below.

A signal S representative of the signal wave included in the target signal can be decomposed into a signal S _SP consisting of frequency components in the signal S _D and SP positions consisting of frequency components in the data position, it represents the noise included in the target signal The signal N1 can be decomposed into a signal N1 _D consisting of frequency components at the data position and a signal N1 _SP consisting of frequency components at the SP position. Similarly, a signal N2 representative of the noise as a reference signal can be decomposed into a signal N2 _SP consisting of frequency components in the signal N2 _D and SP positions consisting of the frequency components in the data location.

The phase amplitude calculation unit 141 adjusts the phase and amplitude of the signal N2 _SP for each frequency component based on the adjustment parameter γ _j as phase amplitude information, which is determined for each frequency component. A signal (-N2 _SP ') that is N2 _SP is generated. The adjustment parameter γ _j represents an adjustment parameter for the j-th frequency component used in the phase amplitude calculation unit 141. For each frequency component, the adder 131 adds the signal (−N2 _SP ′) sent from the phase amplitude calculator 141 to the signal (S _SP + N1 _SP ), thereby adding noise contained in the SP position of the target signal. The signal (S _SP + N1 _SP −N2 _SP ′) after the noise reduction is output. Incidentally, it is not necessary to provide the adjustment parameter γ _j for the frequency component to which the SP signal is not assigned (for example, the frequency component corresponding to l = 1; see FIG. 7), and of course, the frequency component to which the SP signal is not assigned. , The phase and amplitude are not adjusted, the signal (−N2 _SP ′) is generated, and the addition in the adder 131 is not performed.

  The filter 132 performs a filtering process for further reducing external noise remaining in the output signal of the adder 131. For example, the filter 132 is a high-pass filter that reduces high-frequency components included in the output signal of the adder 131.

The equalizing unit 133 is based on a combined signal of the signal (S _SP + N1 _SP −N2 _SP ′) after the filtering process by the filter 132 and the signal (S _D + N1 _D ), and the like for removing distortion in the combined signal. The process is applied. In the following description, the existence of the filtering process by the filter 132 is ignored for simplification of description. Then, the composite signal is represented by (S _D + S _SP + N1 _D + N1 _SP −N2 _SP ′). The equalization unit 133 outputs (S ′ + N1 ′), which is a composite signal (S _D + S _SP + N1 _D + N1 _SP −N2 _SP ′) after the equalization processing.

A signal S ′ in the output signal (S ′ + N1 ′) of the equalization unit 133 is a signal (S _D + S _SP ) after equalization processing, and a signal in the output signal (S ′ + N1 ′) of the equalization unit 133 N1 ′ is a signal after equalization processing (N1 _D + N1 _SP −N2 _SP ′). Since it can be said that the SP signal is not required after the equalization process is executed, the equalization unit 133 performs data from the synthesized signal (S _D + S _SP + N1 _D + N1 _SP −N2 _SP ′) after the equalization process. Only the position signal may be extracted, and the equalized signal S _D may be output as the signal S ′ and the equalized signal N1 _D may be output as the signal N1 ′.

On the other hand, the pseudo-equalizer 144, to the signal N2 _D in the reference signal N2, performs processing that is equivalent to equalization process performed by the equalization section 133. Since the signal N2 _D is a noise signal and the process in the pseudo-equalization unit 144 does not remove the transmission path distortion of the signal wave, it is not appropriate to call the process in the pseudo-equalization unit 144 as an equalization process. Therefore, the process in the pseudo-equalization unit 144 is referred to as a pseudo-equalization process for convenience. The processing conditions of the equalization processing in the equalization unit 133 and the pseudo equalization processing in the pseudo equalization unit 144 are the same. That is, the equalization processing in the equalization unit 133 is realized by multiplying the signal to be equalized by the equalization coefficient, but pseudo equalization using the same equalization coefficient as the equalization coefficient. Do processing. The signal N2 _D after the pseudo equalization processing is output from the pseudo equalization unit 144 as a signal N2 _D ′.

The phase / amplitude calculation unit 142 adjusts the phase and amplitude of the signal N2 _D ′ for each frequency component based on the adjustment parameter β _j defined as the phase / amplitude information for each frequency component. A signal (−N2 _D ″) that is the signal N2 _D ′ is generated. The adjustment parameter β _j represents an adjustment parameter for the j-th frequency component used in the phase amplitude calculation unit 142.

For each frequency component, the adder 134 adds the output signal (−N2 _D ″) of the phase amplitude calculator 142 to the output signal (S ′ + N1 ′) of the equalizer 133 to obtain the data position of the target signal. The contained noise is reduced, and the added signal (S ′ + N1′−N2 _D ″) is output as a signal (S ′ + N1′−N2 ″) after noise reduction. The output signal (S ′ + N1′−N2 ″) of the adder 134 can be sent to the demodulation processor 15 of FIG. 1 as the output signal of the equalization processor 14c.

The MER calculation unit 143 calculates MER representing the reception state of the signal wave based on the output signal (S ′ + N1′−N2 ″) of the addition unit 134. In order to realize noise reduction, it is necessary to appropriately set the adjustment parameters β _j and γ _j as phase amplitude information. In the example shown in FIG. 8, in order to obtain this phase amplitude information, the MER calculation unit 143 The MER calculated in (1) is used.

The MER calculation method based on the signal (S ′ + N1′−N2 ″) in the MER calculation unit 143 is the same as that in the MER calculation unit 114 described in the first embodiment. As a method for determining and updating the adjustment parameter β _j based on the MER, the adjustment parameter α _j based on the MER described in the first embodiment can be applied. In this application, N2, (−N2 ′) and α _j in the description of the method in the first embodiment may be replaced with N2 _D ′, (−N2 _D ″) and β _j , respectively. . Thereby, based on the output signal of the adding unit 134, the adjustment parameter β _j is sequentially updated so that the MER improves (that is, the value representing the MER increases).

In accordance with the updated adjustment parameter β _j , the adjustment parameter γ _j used in the phase amplitude calculation unit 141 is also updated. The latest adjustment parameter γ _j is determined based on the latest adjustment parameter β _j−1 and / or β _{j + 1} . For example, the latest adjustment parameter γ _j is the latest adjustment parameter β _{j−1, the} latest adjustment parameter β _{j + 1,} or an average thereof (β _j−1 + β _{j + 1} ) / 2. The adjustment parameter γ _j may be updated sequentially. Note that the initial values of the adjustment parameters β _j and γ _j can be set in accordance with a method described in a third embodiment to be described later.

  FIG. 9 is a flowchart showing an example of an operation procedure of the equalization processing unit 14c and the phase amplitude adjustment unit 24c of FIG. Each time a signal wave for one symbol is received, a loop process including the processes of steps S11 to S15 is executed once, and the loop process is repeatedly executed until a predetermined end determination condition is satisfied.

In step S11, the noise in the frequency component at the SP position is reduced by the phase amplitude calculation unit 141 and the adding unit 131, and in step S12, the equalization unit 133 reduces the noise in the frequency component at the SP position. Equalization processing is performed on the target signal. Thereafter, in step S13, the output signal of the equalization unit 133 (the signal after the equalization process) and the output signal of the phase amplitude calculation unit 142 are added by the addition unit 134, whereby the noise in the frequency component at the data position is reduced. Reduction is made. Further, in step S14, the MER is calculated from the output signal of the adder 134 that has been subjected to the noise reduction. In step S15, the MER is improved based on the MER (the value representing the MER increases). ( _D ) Update the adjustment parameters β _j and γ _j . For example, the adjustment parameters β _j and γ _j can be updated so that the MER becomes maximum.

  After the update process in step S15, it is determined in step S16 whether a predetermined end determination condition is satisfied. For example, when it is determined that the current MER has increased by a predetermined threshold or more compared to the initial MER (that is, the MER calculated in the first step S14), or the process includes steps S11 to S15. If the loop process is repeatedly executed a prescribed number of times, it is determined that the end determination condition is satisfied, and if not, it is determined that the end determination condition is not satisfied.

If it is determined that the end determination condition is satisfied, the update of the adjustment parameters β _j and γ _j is ended at that time. Thereafter, the adjustment parameter beta _j and gamma _j at that end with the fixed, signal N2 to generate a '(' signal -N @ 2 _D) from _'D processing and signal N2 _SP from the signal (-N @ 2 _SP ') Is generated. On the other hand, if it is determined that the end determination condition is not satisfied, the process returns from step S16 to step S11, and the processes of steps S11 to S15 are executed again.

  According to the second embodiment, the same effect as that of the first embodiment can be obtained.

<< Third Embodiment >>
Next, a third embodiment of the present invention will be described. In the first and second embodiments, the phase amplitude information is obtained by feeding back the MER value. However, in the third embodiment, the phase amplitude information is obtained in advance by performing calibration in advance.

A method for deriving phase amplitude information according to the third embodiment will be described. Please refer to FIG. Now, assuming a noise source NS _j mainly having a j-th discretization frequency component, the noise generated by the noise source NS _j is represented by n _j . The noise n _j is regarded as an impulse, and the impulse response of the transmission path between the noise source NS _j and the antenna 11 and the impulse response of the transmission path between the noise source NS _j and the antenna 21 are represented by h _j1 and h _j2 , respectively. Then, the signals of the noise n _j received by the antennas 11 and 21 are h _j1 n _j and h _j2 n _j , respectively.

Antenna for noise n parameters k _j is multiplied by the multiplication unit 161 to the received signal h _j2 n _j of the antenna 21 for _j, multiplication result by the adding unit _{162 (k j h j2 n j} ) the noise n _j It is considered that noise n _j is removed from the received signal by adding to 11 received signals h _j1 n _j . That is, the output signal (h _j1 n _j + k _j h _j2 n _j ) of the adder 162 is aimed to be zero. In order to realize this, a parameter k _j satisfying the following equation (4) may be used.
h _j1 n _j = −k _j h _j2 n _j (4)

The parameter k _j satisfying Expression (4) is the ratio (−h _j1 / h _j2 ) of the transmission path impulse response at the j-th discretized frequency of the antennas 11 and 21. If the ratio (−h _j1 / h _j2 ) to be matched with the parameter k _j can be obtained, noise can be removed by the configuration shown in FIG.

A method for deriving the parameter k _j will be described. This derivation is performed under a specific reception environment. The receiving apparatus 1 operates in one of a plurality of operation modes including an actual operation mode and a calibration mode (calibration mode). The user can designate an operation mode that is actually operated by operating an operation unit (not shown) provided in the receiving device 1. In the actual operation mode, a baseband signal is generated based on a signal wave and a noise reception signal according to the configuration and method described in the first or second embodiment.

  The specific reception environment is adjusted so that the intensity of the signal received by the antenna 11 is as small as possible, and the noise sources in the vehicle 2 are actually generating noise. In the actual operation mode, basically, each noise source in the vehicle 2 actually generates noise. In the actual operation mode, no special consideration is given to reduce the strength of the signal received by the antenna 11. Therefore, the reception intensity of the signal wave of the antenna 11 when the calibration mode is executed is sufficiently smaller than that in the actual operation mode. Specifically, for example, when the calibration mode is executed, the vehicle 2 is placed in a place where a signal wave hardly reaches (for example, an underground parking lot), and then the engine of the vehicle 2 is idled. Noise is actually generated at each noise source in.

  In the calibration mode, with the antenna 11, the tuner unit 12 and the FFT processing unit 13, and the antenna 21, the tuner unit 22 and the FFT processing unit 23 operating as described above, as shown in FIG. The output signal 23 is supplied to a phase amplitude information setting storage unit 30 (hereinafter abbreviated as setting storage unit 30) provided in the receiving apparatus 1. The setting storage unit 30 can be provided inside or outside the phase amplitude adjustment unit 24 of FIG. The target signal and the reference signal described above are output signals of the FFT processing units 13 and 23 in the actual operation mode. In order to distinguish them, the output signals of the FFT processing units 13 and 23 in the calibration mode are referred to as first and second calibration signals, respectively.

When deriving the parameter k _j (that is, the ratio (−h _j1 / h _j2 )), the setting storage unit 30 determines the jth component that is the main component of the noise n _j from each of the first and second calibration signals. Extract frequency components. Then, it is considered that the phase θ _j1 and the amplitude A _{j1 of} the j-th frequency component extracted from the first calibration signal are 0 ° and 1, respectively. That is, (θ _j1 , A _j1 ) = (0 °, 1) is set so that the extracted component from the first calibration signal is used as a reference.

On the other hand, the setting storage unit 30 obtains the phase θ _j2 and the amplitude A _j2 of the j-th frequency component extracted from the second calibration signal with reference to the phase θ _j1 and the amplitude A _j1 . Thereby, the phase difference (θ _j2 −θ _j1 ) and the amplitude ratio (A _j2 / A _j1 ) are obtained. Since (θ _j1 , A _j1 ) = (0 °, 1), (θ _j2 −θ _j1 ) = θ _j2 and (A _j2 / A _j1 ) = A _j2 .

If the impulse response ratio (−h _j1 / h _j2 ) is a complex number, it contains information on the phase and amplitude, and if the phase difference (θ _j2 −θ _j1 ) and amplitude ratio (A _j2 / A _j1 ) are determined The ratio (−h _j1 / h _j2 ) is uniquely determined. Therefore, the setting storage unit 30 can obtain the parameter k _j that matches the ratio (−h _j1 / h _j2 ) from the phase difference (θ _j2 −θ _j1 ) and the amplitude ratio (A _j2 / A _j1 ).

Although the method for deriving the parameter k _j has been described by paying attention to the noise n _j corresponding to a certain discretized frequency, the setting storage unit 30 performs the above-described process for deriving the parameter k _j as j = 1, 2. 3,... (M-1) and M, and the derived parameters k _{1 to} k _M are stored. When this storage is completed, the calibration mode operation ends.

As shown in FIG. 12, the noise source NS _1, noise source NS ₂ for generating an impulse-like noise n ₂ having a second discrete frequency for generating impulse-like noise n ₁ having a first discrete frequency, If it is considered that noise sources NS _M that generate impulse-like noise n _M having the Mth discretized frequency are individually present in the vehicle 2, parameters k ₁ to k _M Can be used to remove noise from all noise sources. Actually, such M noise sources do not exist independently, but various noises can be effectively removed by providing the parameters k ₁ to k _M for each discretized frequency. It becomes possible.

After the operation in the calibration mode is completed, the operation of the first or second embodiment may be performed using the stored parameters k _{1 to} k _M as the adjustment parameters in the actual operation mode. In this case, the MER is calculated. It is not necessary to update the adjustment parameter based on it. For example, the phase and amplitude calculation unit 113 of FIG. 4, when to generate a signal (-N @ 2 ') from the parameter k ₁ to k _M a adjustment parameter alpha ₁ to? Reference signal using fixedly as _M N2 Thus, the MER calculation unit 114 can be omitted from the phase amplitude adjustment unit 24b, the configuration can be simplified, and the processing speed can be increased by eliminating the need for MER feedback.

However, although the description already described in the first and second embodiments overlaps, the adjustment based on the calculation of the MER after using the stored parameters k _{1 to} k _M as the initial values of the adjustment parameters. It is also possible to update the parameters. For example, the phase and amplitude calculation unit 113 of FIG. 4, so as to generate a signal (-N @ 2 ') from the reference signal N2 using the parameters k ₁ to k _M as an initial value of the adjustment parameter alpha ₁ to? _M, then , according to the method described in the first embodiment, based on the output signal of the equalizer 112, may be updated parameters k ₁ to k _M adjustment parameter was consistent with alpha ₁ to? _M.

<< Deformation, etc. >>
The specific numerical values shown in the above description are merely examples, and as a matter of course, they can be changed to various numerical values.

  In the above-described embodiment, the number of antennas for receiving signal waves and noise is one, but the antenna for receiving signal waves and noise may be composed of a plurality of antennas. That is, a plurality of antennas may be used for diversity reception of signal waves and noise that the antenna 11 should receive.

  In the above-described embodiment, the receiving device 1 is attached to the vehicle 2, but the receiving device 1 may be attached to an object other than the vehicle. However, it is assumed that the object is an object having a noise source that generates noise.

  The receiving apparatus 1 in FIG. 1 can be configured by hardware or a combination of hardware and software. When the receiving apparatus 1 is configured using software, a block diagram of a part realized by software represents a functional block diagram of the part. A function realized using software may be described as a program, and the function may be realized by executing the program on a program execution device (for example, a computer).

DESCRIPTION OF SYMBOLS 1 Receiver 2 Vehicle 11, 22 Antenna 12, 22 Tuner part 13, 23 FFT processing part 14 Noise removal / equalization processing part 15 Demodulation processing part 24 Phase amplitude adjustment part

Claims (6)

A receiving device attached to an object having a noise source,
A first antenna for receiving a signal wave and noise from the noise source;
A first tuner unit that outputs a digital signal on a time axis based on a received signal of the first antenna;
A first converter that converts the output signal of the first tuner unit into a first signal on the frequency axis, which is composed of a plurality of discrete frequency components;
A second antenna for receiving the noise;
A second tuner unit for outputting a digital signal on a time axis based on a received signal of the second antenna;
A second conversion unit that converts the output signal of the second tuner unit into a second signal on the frequency axis, which includes the plurality of frequency components;
A phase / amplitude adjuster for adjusting the phase and amplitude of the second signal for each frequency component;
A receiving apparatus comprising: an adding unit that adds the first signal and the adjusted second signal for each frequency component. The phase amplitude adjustment unit performs the adjustment based on phase amplitude information defining a phase and amplitude adjustment amount for each frequency component, and updates the phase amplitude information according to the addition result of the addition unit. The receiving device according to claim 1. The receiving apparatus operates in any one of a plurality of operation modes including the first and second modes,
In the second mode, the receiving apparatus further includes a setting storage unit that sets and stores the phase amplitude information by obtaining a phase difference and an amplitude ratio between the first signal and the second signal for each frequency component. ,
3. The receiving apparatus according to claim 1, wherein in the first mode, the phase amplitude adjustment unit performs the adjustment using the stored phase amplitude information. In the first mode, the signal from the addition unit using the first and second antennas, the first and second tuner units, the first and second conversion units, the phase amplitude adjustment unit, and the addition unit. A wave baseband signal,
In the second mode, the phase amplitude information is set and stored under a specific reception environment,
The specific reception environment is arranged so that the reception intensity of the signal wave by the first antenna in the second mode is smaller than that in the first mode. Receiver device. The object is a vehicle,
The receiving apparatus according to claim 1, wherein the receiving apparatus is a digital broadcast receiving apparatus that receives a broadcast wave as the signal wave. The receiving apparatus according to claim 5, wherein the second antenna is installed in a space surrounded by a metal part that forms a vehicle body of the vehicle.

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