JP2008312014A - In-vehicle digital broadcast receiver - Google Patents

Abstract

It is possible to increase reception sensitivity and to realize downsizing of a receiving terminal device.
A tuner unit 4 and a receiving terminal device 3 are stored in separate casings. The receiving terminal device 3 includes a demodulating unit 7 and a decoder 9 and is housed in a housing 13 having a radio wave blocking function for absorbing radio waves. The tuner unit 4 is connected to the antenna element unit 1 via the UHF band coaxial cable 2. Located in the vicinity. The terrestrial digital broadcast signal SR of the desired channel received by the antenna element unit 1 is converted into an IF digital broadcast signal SI by the tuner unit 4, demodulated by the demodulation unit 7, and decoded into a video signal and an audio signal by the decoder 9. . Digital harmonic noise generated in the decoder 9 is absorbed by the housing 13 and can be reduced from the antenna input terminal 5 to the tuner unit 4. Moreover, since the coaxial cable 2 can be shortened, the loss resulting from this can be reduced, and the tuner unit 4 is provided as a separate housing, so that the housing 13 of the receiving terminal device 3 can be reduced in size.
[Selection] Figure 1

Description

  The present invention relates to a digital broadcast receiver for a mobile body such as a vehicle, and more particularly to an in-vehicle digital broadcast receiver capable of reducing transmission loss and noise and reducing the size of a main body.

  Conventionally, in a mobile communication system, a digital broadcast receiving apparatus that receives terrestrial digital broadcasting has been used. As such a digital broadcast receiving apparatus, in order to reduce deterioration of reception characteristics due to fading, diversity reception is performed. (For example, refer to Patent Document 1).

  FIG. 10 is a circuit configuration diagram showing the main part of such a terrestrial digital broadcast receiving apparatus, wherein 1a and 1b are antenna element sections, 2a and 2b are coaxial cables, 3 is a receiving terminal apparatus, 4a and 4b are tuner sections, and 5a. 5b are antenna input terminals, 6a and 6b are coaxial cables, 7a and 7b are demodulation units, 8 is a diversity combining unit, and 9 is a decoder.

  In this figure, in this digital broadcast receiving apparatus, a plurality of antenna element units, here, two antenna element units 1a and 1b are used, and the antenna element unit 1a is connected to the receiving terminal device 3 via the coaxial cable 2a. The antenna element portion 1b is connected to the receiving terminal device 3 via the coaxial cable 2b. The receiving terminal device 3 has a configuration in which the tuner units 4a and 4b, the demodulating units 7a and 7b, the diversity combining unit 8 and the decoder 9 are housed in the same casing, and the coaxial cable 2a is the antenna element unit 1a. The coaxial cable 2b is connected between the feeding point of the antenna element part 1b and the antenna input terminal 5b of the tuner part 4b. The tuner unit 4a and the demodulation unit 7a are connected by a coaxial cable 6a, and the tuner unit 4b and the demodulation unit 7b are connected by a coaxial cable 6b.

  The terrestrial digital broadcast signals SRa and SRb received by the antenna element units 1a and 1b are supplied to the tuner units 4a and 4b via the coaxial cables 2a and 2b, respectively, and the same request specified by the user's operation by each. The terrestrial digital broadcast signal of the channel No. 2 is converted into predetermined intermediate frequency (IF) band signals (IF band digital broadcast signals) SIa and SIb. The IF band digital broadcast signals SIa and SIb of these desired channels pass through the coaxial cables 6a and 6b, are supplied to the demodulation units 7a and 7b, are demodulated, and are supplied to the diversity combining unit 8. The diversity combining unit 8 performs a selection diversity method or in-phase combining and converts the signals into digitally processable signals so that the demodulated broadcast signals SDa and SDb of the desired channels from the demodulation units 7a and 7b are in the best reception state. . The demodulated broadcast signal SD output from the diversity combining unit 8 is supplied to the decoder 9 and decoded into an audio signal As and a video signal Vs. These audio signal As and video signal Vs are supplied to a display unit (not shown).

  In this way, by selecting a digital broadcast signal of an arbitrary channel from the broadcast signals of each broadcast station (channel) received by the antenna element units 1a and 1b by a user's selection operation, You can also watch terrestrial digital broadcasts on any channel.

  By the way, when such a terrestrial digital broadcast receiving apparatus is attached to a vehicle such as a passenger car as a moving body, at least one antenna element portion is installed in the vehicle periphery, and a dashboard in front of the vehicle interior (inside the vehicle). A receiving terminal device capable of receiving a television broadcast is disposed therein, and a communication cable such as a coaxial cable is wired between the antenna element unit and the receiving terminal device.

  FIG. 11 is a diagram showing an example of mounting the terrestrial digital broadcast receiving apparatus in a vehicle, where 1c and 1d are antenna element portions, 2c and 2d are coaxial cables, 10 is a vehicle, 11 is in the vehicle, and 12a and 12b are It is a rear glass, and the same code | symbol is attached | subjected to the part corresponding to FIG.

  In the figure, here, assuming that four antenna element portions 1a to 1d are used, two of the antenna element portions 1a and 1b are arranged on the rear glass 12a on the right side surface behind the interior 11 of the vehicle 10, The other two antenna elements 1c and 1d are respectively attached to the rear glass 12b on the left side surface. The receiving terminal device 3 is disposed in a dashboard in front of the vehicle interior 11, and the antenna element portions 1a to 1d and the receiving terminal device 3 are connected by coaxial cables 2a to 2d.

  With this configuration, terrestrial digital broadcast signals received by the antenna element units 1a to 1d are supplied to the receiving terminal device 3 via the coaxial cables 2a to 2d, respectively. Thereby, even a moving vehicle can receive the terrestrial digital broadcast of the desired channel, and the video and audio contents of the received channel are displayed on a display unit (not shown).

Here, it is assumed that each tuner unit connected to the antenna element units 1a to 1d via the coaxial cables 2a to 2d is provided in the reception terminal device 3, but each of the antenna element units 1a to 1d is provided. A technique in which each tuner section is provided in the vicinity is also known (for example, see Patent Document 2).
JP 2006-246364 A JP 2003-332957 A

  The receiving sensitivity of the receiving terminal device of the digital broadcasting receiving device that receives terrestrial digital broadcasting is greatly influenced by the noise figure characteristic of the tuner unit and the loss from the antenna element unit to the antenna input terminal of the tuner unit. In general, a coaxial cable increases signal loss in proportion to frequency and cable length due to its own capacitance and conductor resistance. large.

  In the conventional configuration shown in FIG. 11, the tuner unit in the receiving terminal device 3 installed in the dashboard in front of the vehicle interior 11 from the antenna element units 1 a to 1 d installed in the rear glasses 12 a and 12 b behind the vehicle interior 11. The UHF band coaxial cable to the antenna input terminal has become very long (generally about 3 to 7 m), and this has been a cause of sensitivity deterioration of the in-vehicle digital broadcast receiver.

  Further, in the conventional digital broadcast receiving apparatus having the configuration as shown in FIG. 10, tuner sections 4a and 4b for performing weak analog signal processing and a decoder 9 for performing digital signal processing are provided in the same housing in the receiving terminal apparatus 3. By mixing, logic harmonic noise from the decoder 9 wraps around the antenna input terminals 5a and 5b of the tuner units 4a and 4b. Therefore, sensitivity deterioration is caused even by factors other than the coaxial cable described above. It has occurred.

  The technique described in Patent Document 2 can eliminate the routing of the cable by using wireless communication. However, since the wireless interface is provided in addition to the CPU function, the size is increased, and further, high performance. To have had an effect on the system.

  Furthermore, in conventional terrestrial digital broadcast receivers, a diversity reception configuration or a two diversity reception configuration using one or two antenna element units and a tuner unit is common, but in order to improve reception efficiency during movement. In addition, in the case of a 4-diversity reception configuration using four antenna element units and four tuner units, it is necessary to increase the number of tuner units and demodulator units used, which increases the size of the housing of the receiving terminal device. There was a problem.

  An object of the present invention is to provide an in-vehicle digital broadcast receiving apparatus that can eliminate such problems, increase the receiving sensitivity, and realize downsizing.

  In order to achieve the above object, the present invention is connected to one or a plurality of antenna element units for receiving terrestrial digital broadcast signals of a plurality of channels transmitted from each broadcasting station, and a coaxial cable to the antenna element units. The frequency conversion, gain control and band control of the terrestrial digital signal of the desired channel are performed in synchronization with the selected desired channel among the terrestrial digital broadcast signals of the plurality of channels received by the antenna element unit, and the intermediate frequency A tuner unit that generates a terrestrial digital broadcast signal of a band, a demodulator unit that demodulates the terrestrial digital broadcast signal of the intermediate frequency band from at least the tuner unit into an encoded digital signal, a video signal and a demodulated encoded digital signal A receiving terminal device including a decoder unit that decodes the audio signal, and the tuner unit and the receiving terminal device are separately provided. Of are separated and stored in a housing, the housing of the receiving terminal device is stored, it is characterized in that it has a radio wave shielding function.

  In addition, the present invention is characterized in that the tuner unit and the receiving terminal device are each mounted on separate substrates.

  The present invention further includes one or a plurality of antenna element units that receive terrestrial digital broadcast signals transmitted from each broadcasting station, and are connected to the antenna element units via a coaxial cable so as to be tuned to a broadcast wave of a desired channel. A tuner that performs frequency conversion, gain control, and band control, and generates a terrestrial digital broadcast signal in the intermediate frequency band, and a demodulator that demodulates the terrestrial digital broadcast signal in the intermediate frequency band from at least the tuner unit into an encoded digital signal And a decoder unit that decodes the demodulated encoded digital signal into a video signal and an audio signal, and the tuner unit, the demodulator unit, and the decoder are each stored and separated in separate housings, and the decoder A housing in which is stored has a radio wave blocking function.

  Furthermore, the present invention is characterized in that the casing in which the decoder is stored is a casing having a display unit function.

  Furthermore, the present invention is characterized in that the antenna element portion is mounted on the inner surface or the outer surface of the vehicle, and the tuner portion is disposed in the vicinity of the antenna element portion.

  Furthermore, the present invention is characterized in that at least the feeding point of the antenna element unit is arranged in a casing in which the tuner unit is stored.

  Furthermore, the present invention is characterized in that the feeding point of the antenna element portion and the tuner portion are provided on the same substrate.

  Furthermore, the present invention is characterized in that the antenna element portion is arranged on an outer surface or an inner layer of a casing in which the tuner portion is stored.

  Furthermore, the present invention is characterized in that a signal line for transmitting control data from the demodulator to the tuner is connected between the tuner and the demodulator.

  Furthermore, the present invention is characterized in that the terrestrial digital broadcast signal and the control data are transmitted from the demodulation unit to the tuner unit via a coaxial cable connected between the tuner unit and the demodulation unit. .

  Furthermore, the present invention is characterized in that a tuner section is built in an IC package or the like.

  According to the present invention, the tuner unit that is conventionally mounted in the receiving terminal device together with the demodulating unit and the decoder is arranged in a separate casing, and the receiving unit of the demodulating unit and decoder receives radio waves in the casing. Since it has a blocking function, loss in the high frequency band due to the coaxial cable can be reduced, interference interference in the tuner due to digital harmonic noise from the decoder can be suppressed, and reception sensitivity can be increased. In addition, the receiving terminal device can be downsized without being influenced by the diversity scheme.

  In addition, according to the present invention, since the antenna element portion and the tuner portion are integrated, loss in the high frequency band due to the coaxial cable can be eliminated, and reception sensitivity is improved without depending on the reception channel. In addition, an expensive coaxial cable capable of supporting a UHF band from the antenna element unit to the tuner unit and a connection terminal with the demodulation unit are unnecessary, and the coaxial cable to be used and the connection terminal of the demodulation unit are used in the UHF band. Therefore, it is possible to reduce the frequency to about 1/10 lower than that of the coaxial cable and to reduce the unit price of the cable and the price of the connection terminal.

  Furthermore, according to the present invention, even if the tuner portion has a semiconductor chip configuration, it can be directly mounted on the vehicle glass surface, so that it is possible to eliminate restrictions on the arrangement of the antenna element portion.

  Further, according to the present invention, the control data for the tuner unit can be transmitted from the receiving terminal device, and the control data is transmitted for transmission of the received broadcast signal between the tuner unit and the receiving terminal device. It is possible to transmit via a coaxial cable, and it is possible to increase the placement location of the tuner unit and the housing of the receiving terminal device and the degree of freedom of wiring between them, simplifying the wiring between the tuner unit and the receiving terminal device it can.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing the main part of a first embodiment of an in-vehicle digital broadcast receiving apparatus according to the present invention, wherein 1 is an antenna element unit, 2 is a coaxial cable, 4 is a tuner unit, and 5 is an antenna input. A terminal, 6 is a coaxial cable, 7 is a demodulator, 7c is a connection terminal, 9 is a decoder, and 13 is a casing. The parts corresponding to those in FIG.

  In the figure, this first embodiment is provided with one antenna element unit 1, and the receiving terminal device 3 is provided with a demodulating unit 7 and a decoder 9, and a tuner unit 4. Is separated from the receiving terminal device 3 and mounted on a substrate in a housing such as an IC package. The antenna element unit 1 is connected to an antenna input terminal 5 of a tuner unit 4 by a UHF band coaxial cable 2, and the tuner unit 4 is connected to a demodulation unit in the receiving terminal device 3 via an IF band coaxial cable 6. 7 is connected to the connection terminal 7c.

  The terrestrial digital broadcast signal SR of each channel received by the antenna element unit 1 is transmitted to the tuner unit 4 via the coaxial cable 2. In the tuner unit 4, the terrestrial digital broadcast signal of the desired channel selected by the user's channel selection operation from the input terrestrial digital broadcast signal SR is subjected to frequency conversion, gain control, and band control processing, and a prescribed IF band. The digital broadcast signal SI is supplied to the receiving terminal device 3 via the coaxial cable 6.

  The receiving terminal device 3 has a radio wave shielding function such as absorbing radio waves, and is provided in, for example, a metallic housing 13, in which a desired channel from the tuner unit 4 is provided. A demodulator 7 for demodulating the IF band digital broadcast signal into an encoded digital signal SD, a decoder 9 for performing a conversion process for decoding the encoded digital signal SD from the demodulator 7 into a video signal VS and an audio signal AS, etc. Are mounted on the same substrate or different substrates, or stored and arranged in separate housings. The video signal VS and the audio signal AS are supplied to a display device (not shown) such as a car navigation device or a television receiver, and video display and audio reproduction (hereinafter referred to as display) are performed.

  Here, as shown in FIG. 11, the antenna element unit 1 is provided on the inner surface or the outer surface of the rear part of the vehicle body such as the inner surface or the outer surface of the rear glass of the vehicle, and the receiving terminal device 3 is disposed in the dashboard of the vehicle. . The tuner unit 4 is housed in a housing different from the housing 13 and is provided in a desired space between the antenna element unit 1 and the receiving terminal device 3 in the vehicle. In order to shorten the coaxial cable 2 through which the digital broadcast signal is transmitted and reduce the attenuation of the terrestrial digital broadcast signal SR through the coaxial cable 2, the tuner unit 4 may be installed in the vicinity of the antenna element unit 1. Good.

  According to the above configuration, since the receiving terminal device 3 including the demodulator 7 and the decoder 9 is housed in the housing 13 having a radio wave blocking function, the digital harmonic noise generated from the decoder 9 is the housing. 13 is not cut off and released to the outside, and it can be prevented that this wraps around the antenna input terminal 5 of the tuner unit 4 and is mixed into the received terrestrial digital broadcast signal SR. It is possible to prevent the reception sensitivity from deteriorating due to the noise around the antenna input terminal 5 of the tuner unit 4.

  Further, since the tuner unit 4 can be separated from the receiving terminal device 3 and can be arranged away from the receiving terminal device 3, a part of the digital harmonic noise from the housing 13 of the receiving terminal device 3 from the decoder 9 Even if it is leaking, the amount of the digital harmonic noise that wraps around the antenna input terminal 5 of the tuner section 4 can be sufficiently suppressed, and the coaxial cable 2 between the antenna element section 1 and the tuner section 4 can be shortened. Therefore, the loss of the UHF band terrestrial digital broadcast signal due to the coaxial cable 2 can be reduced. Moreover, if the expensive UHF band coaxial cable 2 is shortened, the IF band coaxial cable 6 becomes correspondingly longer, but the IF band coaxial cable and the connection terminal 5a of the demodulator 7 are connected to the UHF band coaxial cable and connection terminal. Since the unit price is lower than the above, the IF band coaxial cable 6 and the connection terminal 7c are inexpensive, so the cost of the in-vehicle digital broadcast receiver can be reduced.

  Furthermore, since the tuner unit 4 is separated from the housing 13 of the receiving terminal device 3, the housing 13 can be reduced in size, and the space occupied by the housing 13 can be reduced. Restrictions on the installation location can be relaxed. In addition, since the housing 13 of the receiving terminal device 3 can be reduced in size, the receiving terminal device 3 can be installed not only in the above-described dashboard but also in other places such as a rear seat. In this case, since the digital harmonic noise from the decoder 9 of the receiving terminal device 3 is blocked by the casing 13, even if the casing 13 of the receiving terminal 3 is placed close to the tuner unit 4, this digital The influence of the harmonic noise on the tuner unit 4 is not exceptional.

  FIG. 2 is a block diagram showing an application example of the first embodiment shown in FIG. 1, and parts corresponding to those in FIG. 1 and FIG.

  In this figure, this application example is provided with a plurality of antenna elements 1a, 1b (here, two, but not limited to this) to receive diversity. As in the first embodiment shown in FIG. 1, the receiving terminal device 3 is composed of two demodulating units 7a and 7b, a diversity combining unit 8 and a decoder 9 corresponding to the two antenna element units 1a and 1b. The tuner 13 is provided in a casing 13 having a radio wave shielding function, and the two tuner sections 4a and 4b are separately provided in a casing separate from the casing 13.

  The reception process of the terrestrial digital broadcast signal in this application example is the same as that of the prior art shown in FIG. 10 and will not be described. 1 is separated, and the same effect as that of the first embodiment shown in FIG. 1 can be obtained. Compared to a diversity-received in-vehicle digital broadcast receiving apparatus in which the tuner unit is incorporated in the receiving terminal device, the receiving terminal device can be reduced in size, and further, the interchannel interference between the tuner units 4a and 4b can be reduced.

  FIG. 3 is a block diagram showing the main part of the second embodiment of the in-vehicle digital broadcast receiving apparatus according to the present invention. The parts corresponding to those in FIG.

  In the same figure, this 2nd Embodiment isolate | separates the demodulation part 7 and the decoder 9 by another housing | casing. Here, the housing of the decoder 9 can be a housing having a radio wave shielding function, similar to the housing 13 in the first embodiment shown in FIG. 1 or its application example shown in FIG. The decoder 9 may be housed in a display device such as a car navigation device mounted on the vehicle. In this case, the decoder 9 and the tuner unit 4 are further apart from each other, and the digital harmonic noise from the decoder 9 is shielded by the housing of the display device. 9 can significantly reduce the amount of digital harmonic noise from 9 to the antenna input terminal 5 of the tuner section 4.

  Further, the receiving terminal device 3 is composed only of the demodulator 7 and can be greatly reduced in size. Thereby, the restrictions on the installation location of the reception terminal device 3 are relaxed, and the reception terminal device 3 can be installed at an appropriate location.

  Furthermore, by installing the tuner unit 4 in the vicinity of the antenna element unit 1, the coaxial cable 2 between the tuner unit 4 and the antenna element unit 1 can be shortened, and loss due to the coaxial cable 2 can be reduced.

  Thus, also in the second embodiment, the same effect as that of the first embodiment shown in FIG. 1 can be obtained.

  Note that, as an application example of the second embodiment, an in-vehicle digital broadcast receiving apparatus capable of diversity reception using a plurality of antenna element units may be used. In this case, a plurality of demodulation units and diversity configuration units are provided in one housing 13 as a receiving terminal device.

  FIG. 4 is a block diagram showing a main part of a third embodiment of the in-vehicle digital broadcast receiving apparatus according to the present invention, wherein 14 is a feeding point of the antenna element, and parts corresponding to those in FIG. A duplicate description is omitted.

  In the figure, the third embodiment is different from the first embodiment shown in FIG. 1 in that the feeding point 14 of the antenna element unit 1 and the tuner unit 4 are arranged on the same substrate or in the same housing. Is connected to the antenna input terminal 5 of the tuner unit 4 and the other configuration is the same as that of the first embodiment shown in FIG.

  According to such a configuration, the same effect as in the first embodiment can be obtained, but it is not necessary to use a coaxial cable between the antenna element unit 1 and the tuner unit 4 or even if the coaxial cable 2 is used. It becomes very short and the loss due to the coaxial cable 2 can be eliminated, or it can be further reduced as compared with the previous embodiment, and the receiving sensitivity can be further improved.

  FIG. 5 is a block diagram showing the main part of the application example of the third embodiment shown in FIG. 4, wherein 14a and 14b are feeding points, and the portions corresponding to FIG. Description to be omitted is omitted.

  In this figure, this application example is a configuration of two diversity reception in the third embodiment shown in FIG. 4, and in other words, in the application example of the first embodiment shown in FIG. The feeding point 14a of the antenna element unit 1a and the tuner unit 4a are arranged on the same substrate or in the same housing, the feeding point 14a is connected to the antenna input terminal 5a of the tuner unit 4a, and the feeding point of the antenna element unit 1b. 14b and the tuner unit 4b are arranged on the same substrate or in the same housing, and the feeding point 14b is connected to the antenna input terminal 5b of the tuner unit 4b. Other configurations are shown in FIG. Similar to the example.

  In this application example, the same effect as that of the application example shown in FIG. 2 of the first embodiment can be obtained. However, it is necessary to use a coaxial cable between the antenna element units 1a and 1b and the tuner units 4a and 4b. Or, even if the coaxial cable 2 is used, it becomes very short, and the loss due to the coaxial cable 2 can be eliminated, or it can be further reduced as compared with the previous embodiment, and the reception sensitivity can be further increased. Can be improved.

  FIG. 6 is a block diagram showing the main part of the fourth embodiment of the in-vehicle digital broadcast receiving apparatus according to the present invention. The parts corresponding to those in the previous drawings are given the same reference numerals and redundant description is omitted. .

  In this figure, the fourth embodiment is the same as the third embodiment shown in FIG. 4 except that the decoder 9 is separated from the demodulator 7 in a separate housing, as in the second embodiment shown in FIG. Alternatively, it is provided in a display unit (not shown).

  With this configuration, in the fourth embodiment, the same effects as those of the second embodiment shown in FIG. 3 and the third embodiment shown in FIG. 4 can be obtained.

  Also in the fourth embodiment, as in the second embodiment shown in FIG. 3, a plurality of antenna element units can be used to enable diversity reception.

  FIG. 7 is a perspective view showing an essential part of a fifth embodiment of the in-vehicle digital broadcast receiving apparatus according to the present invention. Reference numeral 15 denotes a casing, and parts corresponding to the previous drawings are given the same reference numerals. A duplicate description is omitted.

  In the figure, the fifth embodiment has a configuration in which the antenna element portion 1 is arranged on the surface or inner layer of the casing 15 of the shoe portion 4 in each of the foregoing embodiments and application examples.

  In the fifth embodiment, the same effects as those of the previous embodiments and application examples can be obtained. Furthermore, the tuner unit 4 and the antenna element unit 1 are integrated, so that the in-vehicle digital broadcast receiving apparatus is integrated. Can be further reduced in size.

  FIG. 8 is a block diagram showing the main part of a sixth embodiment of the in-vehicle digital broadcast receiver, wherein 16 is a tuner circuit, 17 is a control unit, 18 is a power source, 19 is a demodulation circuit, and 20 is a control unit. , 21 is a local oscillator, 22 is a PLL circuit, and 23 is a communication line. Parts corresponding to those in the previous drawings are given the same reference numerals, and redundant description is omitted.

  The sixth embodiment relates to a specific example of connection wiring between the tuner unit 4 and the demodulation unit 7 in the previous embodiments and application examples, and here, the first embodiment shown in FIG. However, the decoder 9 in the receiving terminal device 3 is omitted.

  In FIG. 8, the tuner unit 4 includes a tuner circuit 16, a control unit 17, a power source 18, and the like. The tuner circuit 16 is turned on / off by the control unit 17 to supply power supply voltage from the power source 18. Also, the channel is tuned to the selected desired channel among the UHF band terrestrial digital broadcast signals SR supplied from the antenna element unit 1 via the coaxial cable 2, and the terrestrial digital broadcast signal of the desired channel is A frequency signal is converted into an intermediate frequency band (IF band: about 50 MHz) broadcast signal, that is, an IF band digital broadcast signal SI, and only the IF band digital broadcast signal SI of the desired channel is extracted and output. The IF band digital broadcast signal SI of the desired channel is supplied to the demodulator 7 of the receiving terminal device 3 via the coaxial cable 6.

  In the demodulator 7, the IF band digital broadcast signal SI is supplied to the demodulator circuit 19, demodulated using the carrier signal generated by the local oscillator 21, the PLL circuit 22, and the like, and the decoder 9 (see FIG. 1).

  The demodulator 7 also includes a control unit 20 having a power source, a microcomputer, and the like. The control unit 20 and the control unit 17 in the tuner unit 4 are connected by a communication line 23. An operation signal SO is input to the control unit 20 in accordance with an operation (power on / off operation, channel selection operation, etc.) by a user of an operation unit (not shown), and the power of the demodulator 7 is supplied in accordance with the operation signal SO. The control data DS is transmitted to the control unit 17 of the tuner unit 4 via the communication line 23.

  Therefore, now, when the in-vehicle digital broadcast receiving apparatus is in a power-off state and the user turns on the power with the operation unit, the control unit 20 in the receiving terminal apparatus 3 is operated by the operation signal SO supplied thereby. Then, the demodulator 7 is powered on, and at the same time, the power-on control data DS is transmitted to the tuner unit 4 via the communication line 23. In the tuner unit 4, when the control data DS is received, the control unit 17 turns on the power source 18 to supply the power source voltage to the tuner circuit 16, and the tuner circuit 16 is turned on.

  Similarly, when the user turns off the power with the operation unit, in the receiving terminal device 3, the demodulating unit 7 is turned off by the control unit 20, and the tuner unit 4 receives the signal from the control unit 20. Based on the power-off control data DS, the control unit 17 turns off the power source 18 to turn the tuner circuit 16 into a power-off state.

  Further, when the on-vehicle digital broadcast receiving apparatus is in a power-on state, when the user performs a selection operation of a desired channel with the operation unit, an operation signal SO for instructing the selected desired channel is transmitted to the control unit 20 of the receiving terminal device 3. To be supplied. The control unit 20 transmits the control data DS instructing the desired channel to the control unit 17 of the tuner unit 4 via the communication line 23 while keeping the demodulation unit 7 in a power-on state. When receiving the control data DS, the control unit 17 controls the tuner circuit 16 so as to tune to the selected desired channel. As a result, the desired channel selected by the user using the operation unit is received.

  Note that the demodulation circuit 19, the local oscillator 21, the PLL circuit 22, the control unit 20, and the like of the demodulation unit 7 may be provided on separate substrates, but are mounted on the same substrate or stored in the same housing. You may be allowed to.

  In this way, the control data DS corresponding to the operation of the user's operation unit is transmitted from the receiving terminal device 3 to the tuner unit 4, so that the tuner unit 4 is set to a state corresponding to this operation. Thus, the channel desired by the user can be selected.

  FIG. 9 is a block diagram showing the main part of the seventh embodiment of the in-vehicle digital broadcast receiving apparatus, wherein 24 is a BPF, 25 is an LPF (low-pass filter), 26 is a BPF, and 27 is an LPF. Portions corresponding to 8 are assigned the same reference numerals and redundant description is omitted.

  The seventh embodiment relates to a specific example of connection wiring between the tuner unit 4 and the demodulation unit 7 in each of the previous embodiments and application examples. Here, the seventh embodiment is the same as the previous embodiment of FIG. The first embodiment shown in FIG. 1 will be described as an example, but the decoder 9 in the receiving terminal device 3 is omitted. In the application examples shown in FIG. 2 and FIG. 5, the diversity combining unit and the decoder are omitted.

  In FIG. 9, in the tuner unit 4, the UHF band terrestrial digital broadcast signal SR of the desired channel from the coaxial cable 2 is converted into an IF band digital broadcast signal SI by the tuner circuit 16. A BPF 24 having a pass band for the IF band digital broadcast signal SI is connected to the tuner circuit 16 and provided in the casing of the tuner unit 4. The IF band of the desired channel output from the tuner circuit 16 is provided. The digital broadcast signal SI is supplied to the receiving terminal 3 via the BPF 24 and further via the coaxial cable 6. The tuner unit 4 is provided with an LPF 25 connected to the coaxial cable 6, and an output terminal of the LPF 25 is connected to an input terminal of a control unit 17 that controls the tuner circuit 16.

  In the receiving terminal device 3, in addition to the demodulator 7, a BPF 26 and an LPF 27 are provided. The coaxial cable 6 from the tuner unit 4 is connected to the BPF 26, and the output terminal of the BPF 26 is connected to the demodulation circuit 19 of the demodulation unit 7. The pass band of the BPF 26 is set to be equal to the pass band of the BPF 24 in the tuner unit 4. Therefore, the IF band digital broadcast signal IR of the desired channel supplied from the tuner circuit 16 of the tuner unit 4 via the coaxial cable 6. Is demodulated by the demodulation circuit 19 and supplied to a decoder (or a diversity combiner not shown).

  In the receiving terminal device 3, the LPF 27 connected to the control unit 20 is connected to the coaxial cable 6. The pass band of the LPF 25 in the LPF 27 and the tuner unit 4 is equal, is equal to or higher than the frequency of the control data DS output from the control unit 20 (for example, the KHz order of about 400 KHz), and the lower limit frequency of the pass bands of the BPFs 24 and 26 A lower cutoff frequency (upper limit frequency) is set, and the pass band (about 50 MHz) of the BPFs 24 and 26 and the frequency range of the pass band are greatly different. Therefore, the IF band digital broadcast signal of the desired channel output from the BPF 24 The IR is blocked by the LPF 25 and is not supplied to the control unit 17, and the IR is blocked by the LPF 27 and is not supplied to the control unit 20.

  On the other hand, the control data DS output from the control unit 20 in response to an operation signal SO from an operation unit (not shown) has a frequency of, for example, the order of 400 KHz, and thus passes through the LPF 27 and the coaxial cable 6. Is supplied to the tuner unit 4 via the BPF 26 and blocked by the BPF 26 and not supplied to the demodulation circuit 19. In the tuner unit 4, the control data DS is supplied to the control unit 17 via the LPF 25, and the control unit 17 performs control according to the control data DS as in the sixth embodiment shown in FIG. Do. The control data DS is blocked by the BPF 24 and is not supplied to the tuner circuit 16. As a result, the IF band digital broadcast signal IR from the tuner unit 4 is supplied to the demodulation circuit 19 without being mixed with the control data DS output from the control unit 20.

  Instead of the BPFs 24 and 26, an HPF having a pass band equal to or higher than the lower limit cutoff frequency of the BPFs 24 and 26 may be used.

  In this way, the same effects as in the sixth embodiment can be obtained, and the coaxial cable 6 connecting the tuner unit 4 and the demodulator unit 7 can be used to transmit control data from the demodulator unit 7 to the tuner unit 4. Therefore, a necessary signal can be transmitted and received with one coaxial cable without using a plurality of cables, and a special cable need not be used. For this reason, the overall cost of the in-vehicle digital broadcast receiving apparatus can be reduced, and a plurality of cables can be unified, and the degree of freedom of arrangement, attachment, and wiring of each housing can be increased.

  According to the present invention, the present invention can be effectively applied to all receiving apparatuses that receive terrestrial digital broadcasting and digital audio broadcasting.

FIG. 1 is a block diagram showing the main part of a first embodiment of an in-vehicle digital broadcast receiver according to the present invention. FIG. 2 is a block diagram showing an application example of the first embodiment shown in FIG. FIG. 3 is a block diagram showing a main part of a second embodiment of the in-vehicle digital broadcast receiving apparatus according to the present invention. FIG. 4 is a block diagram showing a main part of a third embodiment of the in-vehicle digital broadcast receiving apparatus according to the present invention. FIG. 5 is a block diagram showing a main part of an application example of the third embodiment shown in FIG. FIG. 6 is a block diagram showing the main part of the fourth embodiment of the in-vehicle digital broadcast receiving apparatus according to the present invention. FIG. 7 is a perspective view showing an essential part of a fifth embodiment of the in-vehicle digital broadcast receiving apparatus according to the present invention. FIG. 8 is a block diagram showing a main part of a sixth embodiment of the in-vehicle digital broadcast receiving apparatus. FIG. It is a circuit block diagram which shows the principal part of the conventional terrestrial digital broadcast receiver. It is a figure which shows the example of mounting in a vehicle of the conventional terrestrial digital broadcast receiver.

Explanation of symbols

1, 1a, 1b Antenna element part 2, 2a, 2b Coaxial cable 3 Receiving terminal device 4, 4a, 4b Tuner part 5, 5a, 5b Antenna input terminal 6, 6a, 6b Coaxial cable 7, 7a, 7b Demodulation part 7c Connection Terminal 8 Diversity combining unit 9 Decoder 13 Housing 14, 14a, 14b Antenna element feeding point 15 Housing 16 Tuner circuit 17 Control unit 18 Power supply 19 Demodulation circuit 20 Control unit 21 Local oscillator 22 PLL circuit 23 Communication line 24 BPF
25 LPF
26 BPF
27 LPF

Claims (11)

One or a plurality of antenna element units for receiving digital terrestrial broadcast signals of a plurality of channels transmitted from each broadcasting station;
A terrestrial digital signal of the desired channel is connected to the antenna element unit via a coaxial cable and is tuned to a selected desired channel among the terrestrial digital broadcast signals of the plurality of channels received by the antenna element unit. A tuner that performs frequency conversion, gain control, band control, and generates terrestrial digital broadcast signals in the intermediate frequency band;
Reception comprising at least a demodulator that demodulates the terrestrial digital broadcast signal of the intermediate frequency band from the tuner into an encoded digital signal and a decoder that decodes the demodulated encoded digital signal into a video signal and an audio signal A terminal device, and
The tuner unit and the receiving terminal device are each stored and separated in separate housings,
The in-vehicle digital broadcast receiving apparatus, wherein the housing in which the receiving terminal apparatus is stored has a radio wave blocking function. In claim 1,
The in-vehicle digital broadcast receiving device, wherein the tuner unit and the receiving terminal device are each mounted on separate substrates. One or a plurality of antenna element units for receiving a terrestrial digital broadcast signal transmitted from each broadcasting station;
A terrestrial digital signal of the desired channel is connected to the antenna element unit via a coaxial cable and is tuned to a selected desired channel among the terrestrial digital broadcast signals of the plurality of channels received by the antenna element unit. A tuner that performs frequency conversion, gain control, band control, and generates terrestrial digital broadcast signals in the intermediate frequency band;
A demodulator that demodulates at least the intermediate frequency band terrestrial digital broadcast signal from the tuner into an encoded digital signal;
A decoder unit that decodes the demodulated encoded digital signal into a video signal and an audio signal;
The tuner unit, the demodulating unit, and the decoder are each stored and separated in separate cases, and the case in which the decoder is stored has a radio wave blocking function. Digital broadcast receiver. In claim 3,
The in-vehicle digital broadcast receiving apparatus, wherein the housing in which the decoder is stored is a housing having a display function. In any one of Claims 1-4,
The antenna element portion is mounted on the inner surface or outer surface of the vehicle,
The in-vehicle digital broadcast receiving apparatus, wherein the tuner section is disposed in the vicinity of the antenna element section. In any one of Claims 1-5,
At least a feeding point of the antenna element unit is arranged in the casing in which the tuner unit is stored. In claim 6,
The in-vehicle digital broadcast receiving apparatus, wherein the feeding point of the antenna element unit and the tuner unit are provided on the same substrate. In claim 6,
The in-vehicle digital broadcast receiving apparatus, wherein the antenna element unit is disposed on an outer surface or an inner layer of the casing in which the tuner unit is stored. In any one of Claims 1-8,
A vehicle-mounted digital broadcast receiving apparatus, wherein a signal line for transmitting control data from the demodulator to the tuner is connected between the tuner and the demodulator. In any one of Claims 1-8,
The in-vehicle digital transmission characterized in that the terrestrial digital broadcast signal and control data are transmitted from the demodulation unit to the tuner unit via the coaxial cable connected between the tuner unit and the demodulation unit. Broadcast receiving device. In any one of Claims 1-10,
A vehicle-mounted digital broadcast receiver characterized in that a tuner unit is built in an IC package or the like.

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