JP2013098767A - Wireless communication terminal and signal processing circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately remove noise components from received wireless signals.SOLUTION: A wireless communication terminal 1 comprises: a first antenna 10 for receiving first wireless signals; a demodulation unit 62 for demodulating the wireless signals into digital signals; a processor 70 for executing processing based on the digital signals; a shield unit 90 for electromagnetically isolating the processor from the outside; a second antenna 110 which is installed inside of the shield unit; and a noise cancelling unit 50 for removing predetermined signal components based on second wireless signals received by the second antenna, from the first wireless signals.

Description

  The present invention relates to a technical field of a radio communication terminal that receives a radio signal and a signal processing circuit mounted on the radio communication terminal or the like.

  As this type of wireless communication terminal, a mobile phone, a portable information terminal, and the like are known. In recent years, this type of wireless communication terminal is required to be multi-functional, and there is also a demand for weight reduction and size reduction so that it can be easily carried.

  As the weight and size of wireless communication terminals are pursued, the mounting density of components in the wireless communication terminals increases, so there is a trade-off relationship with a decrease in the degree of freedom of component arrangement inside the wireless communication terminals. . In addition, there are cases where the degree of freedom of component placement is further limited due to demands from customers regarding the design of wireless communication terminals.

  By restricting the arrangement of components in this way, it becomes difficult to secure a mounting interval between a communication antenna and a component or circuit that generates noise in a wireless communication terminal. This causes a technical problem that it is easy to receive interference. At this time, for the part that generates noise, for example, an electromagnetic shield is applied to suppress noise interference. However, depending on the state of component arrangement, noise interference may not be completely eliminated, which may affect communication. Therefore, in the field of development of portable wireless communication terminals, suppression or reduction of such noise interference has been a technical issue.

  For example, in the prior art document described below, an auxiliary antenna is provided separately from the communication antenna, and the phase and amplitude of the noise element received by the auxiliary antenna are adjusted and received by the communication antenna. A configuration is described in which a noise element is eliminated by synthesizing the received radio signal.

Japanese Patent Laid-Open No. 11-27160

  As described above, noise interference inside the wireless communication terminal cannot be completely eliminated even if the electromagnetic shield is simply applied. This leads to deterioration in reception performance of the wireless communication terminal due to noise interference with a desired reception signal. In addition, when the amount of noise interference becomes dominant with respect to performance, there is a possibility that it may hinder signal quality and performance improvement.

  In the above-described prior art documents, the mounting position of the auxiliary antenna is set on the inner back side of the wireless communication terminal for the purpose of receiving only the noise element without receiving the wireless signal. However, in such a configuration, it is not possible to completely avoid the auxiliary antenna receiving a radio signal. For this reason, the radio signal received by the auxiliary antenna is combined with the radio signal received by the communication antenna. For this reason, there is a technical problem that the quality of the received signal obtained from the radio signal received by the communication antenna is deteriorated. In addition, since the auxiliary antenna receives electrical noise generated in the wireless communication terminal widely and indiscriminately, noise components that do not interfere with the wireless signal received by the communication antenna are also subject to synthesis. On the other hand, it can be a factor that increases interference of noise in the received signal.

  The present invention has been made in view of the technical problems described above, and a radio communication terminal capable of eliminating a suitable noise component without causing an increase in unnecessary noise interference with respect to a received signal, and It is an object to provide a signal processing circuit.

  In order to solve the above problem, the disclosed wireless communication terminal includes a first antenna, a demodulation unit, a processor, a shield unit, a second antenna, and a noise cancellation unit. The first antenna receives the first radio signal. The demodulator demodulates the radio signal into a digital signal. The processor performs processing based on the digital signal. The shield part electromagnetically shields the processor from the outside. The second antenna is provided inside the shield part. The noise cancellation unit removes a predetermined signal component based on the second radio signal received by the second antenna from the first radio signal.

  In addition, the disclosed signal processing circuit is provided in a wireless communication terminal that receives a first wireless signal, and includes a signal processing unit and an antenna provided inside a shield unit that electromagnetically shields the inside and the outside, and noise cancellation A part. Each part of the signal processing circuit of the present invention performs the same operation as each part of the above-described wireless communication terminal of the present invention inside the wireless communication terminal.

  According to the disclosed wireless communication terminal, it is possible to suitably remove the noise component from the received wireless signal (for example, the first wireless signal described above). For this reason, improvement in the quality of the received signal can be expected.

It is a block diagram which shows the structural example of a portable terminal. It is a perspective view which shows the structural example of a shield part. It is a block diagram which shows the structural example of a memory. It is a flowchart which shows the flow of operation | movement of a noise cancellation control part. It is a flowchart which shows the flow of the amplitude processing operation | movement of a noise cancellation control part. It is a flowchart which shows the flow of the phase processing operation | movement of a noise cancellation control part. It is a block diagram which shows the modification of a radio | wireless communication terminal. It is a block diagram which shows the modification of a radio | wireless communication terminal. It is a block diagram which shows the modification of a radio | wireless communication terminal.

  Embodiments for carrying out the invention will be described below.

(1) Configuration Example A configuration example of an embodiment of the disclosed wireless communication terminal will be described with reference to the drawings. FIG. 1 is a block diagram illustrating an example of a configuration of a mobile terminal 1 that is an example of a disclosed wireless communication terminal and that has a data broadcast reception and display function.

  As shown in FIG. 1, the mobile terminal 1 includes a one-segment antenna 10, a matching unit 20, a filter 30, an amplification unit 40, a noise cancellation unit 50, a tuner 61 and a demodulation circuit 62, a modem (MODEM) 60, and signal processing MPU (Micro Processing Unit) 70 including a unit 71 and a noise cancellation control unit 72, a memory 80, a shield unit 90, a display unit 101, an auxiliary antenna 110, an amplitude adjustment unit 120, and a phase adjustment unit 130.

  In the mobile terminal 1, a radio signal for transmitting content data such as data broadcast (so-called one-segment broadcast content data) is received by the one-segment antenna 10. The received radio signal (hereinafter described as a received signal) is signal-matched by the matching unit 20 and the filter 30, and a component in a predetermined band is extracted. The extracted received signal component is amplified by the amplification unit 40 and input to the noise cancellation unit 50.

  The noise cancellation unit 50 synthesizes a predetermined signal component input from the phase adjustment unit 130 with respect to the input reception signal, thereby removing signal components added to the reception signal (in other words, Adder).

  The received signal from which the noise component has been removed is input to the modem 60. In the modem 60, a tuner 61 performs a tuning process for reproducing and displaying a desired data broadcast content (for example, a data broadcast channel) according to a user operation or the like. In the modem 60, the demodulation circuit 62 performs a demodulation process on the received signal to a digital signal. Further, the demodulation circuit 62 monitors the signal quality of the received signal. For example, the demodulation circuit 62 estimates the signal quality of the received signal by measuring a BER (Bit Error Rate).

  The digital signal demodulated by the demodulation circuit 62 is input to the MPU 70. In the MPU 70, for example, the digital signal demodulated in the demodulation circuit 62 is processed by a signal processing unit 71 realized by a process (so-called logical processing block) executed in the MPU 70. As a result, the digital signal is converted into a data format that can be output as an image or video. This image or video is actually displayed by the display unit 101. Such a display unit 101 is a display device such as a liquid crystal display.

  In this embodiment, the MPU 70 is provided inside a shield part 90 that electrically shields the inside and the outside. For this reason, for example, the MPU 70 is isolated from an external signal (for example, a radio signal received by the one-segment antenna 10). Further, the noise component generated by the operation of the MPU 70 is blocked or alleviated due to the shield unit 90, and the noise component received by the one-segment antenna 10 is mitigated as compared with the case where the shield unit 90 does not exist. is there.

  Further, a memory 80 and an auxiliary antenna 110 are provided inside the shield part 90. The memory 80 and the auxiliary antenna 110 will be described later in order.

  An example of such a shield part 90 is shown in FIG. FIG. 2 is a perspective view illustrating a configuration example of the shield unit 90.

  As shown in FIG. 2A, the MPU 70, the memory 80, and the auxiliary antenna 110 are arranged on the printed circuit board so as to be adjacent to each other (or to be integrated with each other). On the other hand, the matching unit 20 (including the connection unit with the one-segment antenna 10), the filter 30, the amplification unit 40, the modem 60, the amplitude adjustment unit 120 described later, and the phase adjustment unit 130 described later (or the noise cancellation unit). 50, etc.) are arranged so as to be adjacent to each other (or so as to be integrated with each other) and physically separated from the MPU 70, the memory 80, and the auxiliary antenna 110. Arranged on the printed circuit board. On such a printed circuit board, the MPU 70, the memory 80, and the auxiliary antenna 110 are covered with a shield portion 90, for example, a sheet metal. However, not only the sheet metal but also the one that can block or mitigate noise components from the surroundings (in other words, the outside) can be used as the shield part 90.

  In FIG. 1 again, the auxiliary antenna 110 is an antenna provided in the shield part 90. Since the auxiliary antenna 110 is electrically cut off from the outside of the shield unit 90, for example, an external signal (for example, a radio signal received by the one-segment antenna 10) is not received. On the other hand, the auxiliary antenna 110 has a noise component generated by the operation of a part of circuits (specifically, a circuit disposed inside the shield unit 90, such as the MPU 80) provided in the mobile terminal 1. Receive. The auxiliary antenna 110 is connected to the amplitude adjustment unit 120 in such a manner that a signal can be input, and a signal indicating a received noise component (hereinafter described as a noise cancellation signal) is supplied to the amplitude adjustment unit 120. input.

  The amplitude adjustment unit 120 adjusts the amplitude of the noise cancellation signal input from the auxiliary antenna 110 in accordance with a control signal (for example, an amplitude adjustment value) from the noise cancellation control unit 72. The amplitude adjustment unit 120 inputs a noise cancellation signal with the amplitude adjusted appropriately to the phase adjustment unit 130.

  The phase adjustment unit 130 adjusts the phase of the noise cancellation signal input from the phase adjustment unit 120 in accordance with a control signal (for example, a phase adjustment value) from the noise cancellation control unit 72. The phase adjustment unit 130 inputs a noise cancellation signal whose phase has been appropriately adjusted to the noise cancellation unit 50.

  The noise cancellation control unit 72 is a control unit realized by a process (so-called logical processing block) executed in the MPU 70. The noise cancellation control unit 72 controls the operations of the amplitude adjustment unit 120 and the phase adjustment unit 130 according to the state of the signal quality of the reception signal monitored by the demodulation circuit 62. Specifically, the noise cancellation control unit 72 adjusts the amplitude of the noise cancellation signal to the amplitude adjustment unit 120 so that the signal quality state of the reception signal monitored by the demodulation circuit 62 becomes a desired state. A target value (that is, an amplitude adjustment value) is set. Thereafter, the noise cancellation control unit 72 inputs the set amplitude adjustment value to the amplitude adjustment unit 120 to perform feedback processing for removing noise components included in the received signal. Further, the noise cancellation control unit 72 causes the phase adjustment unit 130 to adjust the phase of the noise cancellation signal so that the signal quality of the received signal monitored by the demodulation circuit 62 becomes a desired state. Set the value (that is, the phase adjustment value). Thereafter, the noise cancellation control unit 72 inputs the set phase adjustment value to the phase adjustment unit 130 to perform feedback processing for removing the noise component included in the received signal.

  The amplitude adjustment value and the phase adjustment value set by the noise cancellation control unit 72 are stored in the memory 80, for example. Hereinafter, a configuration example of the memory 80 will be described with reference to FIG. FIG. 3 is a block diagram illustrating a configuration example of the memory 80.

  As shown in FIG. 3, the memory 80 includes a first register 142, a second register 143, an initial value memory 144, a determination value memory 145, an amplitude adjustment value register 146, and a phase adjustment value register 147.

  The first register 142 and the second register 143 are storage devices that store data relating to the signal quality of a received signal such as BER, for example. The first register 142 temporarily holds the BER of the reception signal input from the demodulation circuit 62.

  The initial value memory 144 is a memory that holds an initial value of a preset value for adjusting the phase and amplitude of the noise cancellation signal. The noise cancellation control unit 72 may set initial values of the adjustment values of the phase and amplitude of the noise cancellation signal according to the data collected by the processing so far, and may update the initial value memory 144 as appropriate. In addition, the noise cancellation control unit 72 calculates the BER of the received signal when the initial values of the phase and amplitude adjustment values of the noise cancellation signal stored in the initial value memory 144 are applied, and stores the BER in the second register 143. .

  The determination value memory 145 is a memory that stores information indicating reception quality that is a target when a noise component is removed from a reception signal by combining noise cancellation signals. For example, the BER required when the image or video transmitted by data broadcasting is normally displayed on the display unit 101 is held as the determination BER.

  The amplitude adjustment value register 146 and the phase adjustment value register 147 receive the input of the amplitude adjustment value and the phase adjustment value set in the noise cancellation control unit 72 and input them to the amplitude adjustment unit 120 and the phase adjustment unit 130, respectively.

  According to such a configuration and operation of the mobile terminal 1, the auxiliary antenna 110 is blocked from receiving a received signal by the shield unit 90, while a part of circuits (specifically, the mobile terminal 1 includes). , A circuit arranged inside the shield unit 90, for example, receiving noise components generated by the operation of the MPU 80 or the like. The noise cancellation signal generated by adjusting the amplitude and phase of the received noise component in accordance with the signal quality of the received signal monitored by the demodulation circuit 62 is combined with the received signal, so that the received signal is converted into the received signal. It becomes possible to remove a noise component resulting from the operation of the circuit inside the mobile terminal 1 included. The operation of the mobile terminal 1 including the adjustment of the amplitude and phase of the noise cancellation signal will be described below.

  The portable terminal 1 further includes a camera 102, a power supply audio 103, a portable communication unit 104, a BT (Bluetooth (registered trademark)) communication unit 105, a portable communication antenna 106, and a BT communication antenna 107. These configurations may be the same as those of an existing mobile terminal.

(2) Operation Example With reference to FIG. 4 to FIG. 6, the flow of operation when removing the noise component from the received signal in the mobile terminal 1 will be described. 4 to 6 are flowcharts illustrating the flow of operations performed by the amplitude adjustment unit 120, the phase adjustment unit 130, and the noise cancellation control unit 72 of the mobile terminal 1.

  As shown in FIG. 3, first, the noise cancellation control unit 72 of the mobile terminal 1 sets the amplitude adjustment value of the noise cancellation signal stored in the initial value memory 144 when the mobile terminal 1 starts receiving content such as data broadcasting. The phase adjustment value is stored in the amplitude adjustment value register 146 and the phase adjustment value register 147 (step S101).

  The amplitude adjustment value register 146 inputs the stored initial value of the amplitude adjustment value to the amplitude adjustment unit 120. The amplitude adjustment unit 120 adjusts the amplitude of the noise cancellation signal input from the auxiliary antenna 110 according to the initial value of the input amplitude adjustment value, and then inputs the signal to the phase adjustment unit 130.

  The phase adjustment value register 147 inputs the stored initial value of the phase adjustment value to the phase adjustment unit 130. The phase adjustment unit 130 adjusts the phase of the noise cancellation signal input from the amplitude adjustment unit 120 according to the initial value of the input phase adjustment value, and then inputs the signal to the noise cancellation unit 50.

  The noise cancellation unit 50 synthesizes the received noise cancellation signal with the received signal and inputs the synthesized signal to the modem 60. The reception signal combined with the noise cancellation signal in this way is subjected to BER measurement indicating the signal quality in the demodulation circuit 62. The demodulator circuit 62 inputs the measured BER to the noise cancellation controller 72. The noise cancellation control unit 72 receives the BER of the received signal via the first register 142 or directly from the demodulation circuit 62, and stores the BER of the received signal in the second register 143 (step S102).

  Subsequently, the noise cancellation control unit 72 determines whether the previously executed process was a process for adjusting the amplitude adjustment value applied to the noise cancellation signal or a process for adjusting the phase adjustment value (step S103).

  When the process at the previous execution is a process for adjusting the phase adjustment value (step S103: Yes), the noise cancellation control unit 72 executes a process for adjusting the amplitude adjustment value (step S104). On the other hand, when the process at the previous execution is a process for adjusting the amplitude adjustment value (step S103: No), the noise cancel control unit 72 executes a process for adjusting the phase adjustment value (step S105). By this determination, a processing loop for alternately adjusting the amplitude adjustment value and the phase adjustment value is formed.

  Here, the flow of processing for adjusting the amplitude adjustment value will be described with reference to FIG. FIG. 5 is a flowchart showing a flow of processing for adjusting the amplitude adjustment value. In the process of adjusting the amplitude adjustment value, the amplitude of the noise cancellation signal used for removing the noise component from the received signal so that the data broadcast content can be properly viewed on the basis of the BER measured by the demodulation circuit 62. Processing for adjusting the adjustment value is performed.

  First, the noise cancellation control unit 72 uses a value obtained by adding a predetermined amplitude value X to the amplitude adjustment value at the time of the previous processing (for example, the initial value of the amplitude adjustment value at the first execution) as a new amplitude. An adjustment value is set (step S201). Then, the value of the amplitude adjustment value register 146 is updated by applying the newly set amplitude setting value (step S202). As a result, the amplitude of the noise cancellation signal is changed, so that a change occurs in the noise component removed from the reception signal to which the noise cancellation signal is added. As a result, the signal quality of the received signal also changes. The demodulation circuit 62 measures the BER of such a received signal and inputs it to the first register 142.

  Here, the noise cancellation control unit 72 compares the BER of the reception signal stored in the first register 142 with the BER of the reception signal stored in the second register 143 (step S203). The BER stored in the first register 142 is the BER of the received signal when the amplitude setting value set in step S201 (that is, the amplitude setting value at the previous processing + X) is applied to the noise cancellation signal. . On the other hand, the BER stored in the second register 143 is the BER of the received signal when the amplitude setting value at the previous processing (for example, the initial value of the amplitude setting value at the time of the first processing) is applied.

  When the BER stored in the first register 142 is lower than the BER stored in the second register 143 (step S203: Yes), the noise cancellation control unit 72 receives the received signal when the newly set amplitude adjustment value is applied. The BER stored in the first register 142 indicating the signal quality is stored in the second register 143 (step S204).

  On the other hand, when the BER stored in the first register 142 is equal to or higher than the BER stored in the second register 143 (step S203: No), the noise cancellation control unit 72 determines the amplitude adjustment value in the previous process. Then, a value obtained by subtracting a predetermined amplitude value X (or a different amplitude value X ′) is set as a new amplitude adjustment value (step S205). Then, by applying the newly set amplitude setting value, the value of the amplitude adjustment value register 146 is updated (step S206). Thereby, since the amplitude of the noise cancellation signal is changed, a change occurs in the noise component removed from the reception signal in which the noise cancellation signal is synthesized. As a result, the signal quality of the received signal also changes. The demodulation circuit 62 measures the BER of such a received signal and inputs it to the first register 142. The noise cancellation control unit 72 stores the BER stored in the first register 142 indicating the signal quality of the received signal when the newly set amplitude adjustment value is applied in the second register 143 (step S204).

  In the first register 142, the BER of the received signal when a newly set amplitude adjustment value is applied, and in the second register 143, the BER of the received signal when the amplitude adjustment value set during the previous processing is applied. Each is stored. By comparing these, it is possible to determine whether the signal quality of the received signal is improved or deteriorated when a predetermined amplitude value X is added to or subtracted from the amplitude adjustment value. Therefore, according to the adjustment process of the amplitude adjustment value described with reference to FIG. 5, the amplitude adjustment value applied to the noise cancellation signal is received while receiving feedback from the demodulation circuit 62 that measures the BER of the received signal. Adjustment is performed by adding or subtracting a predetermined amplitude value X.

  Next, the flow of processing for adjusting the phase adjustment value will be described with reference to FIG. FIG. 6 is a flowchart showing a flow of processing for adjusting the phase adjustment value. In the process of adjusting the phase adjustment value, the phase of the noise cancellation signal used to remove the noise component from the received signal so that the data broadcast content can be properly viewed on the basis of the BER measured by the demodulation circuit 62. Processing for adjusting the adjustment value is performed.

  First, the noise cancellation control unit 72 adds a value obtained by adding a predetermined phase value Y to the phase adjustment value at the time of the previous processing (for example, the initial value of the phase adjustment value at the first execution) as a new phase. An adjustment value is set (step S301). Then, the value of the phase adjustment value register 147 is updated by applying the newly set phase setting value (step S302). As a result, the phase of the noise cancellation signal is changed, and a change occurs in the noise component that is removed from the reception signal that is synthesized with the noise cancellation signal. As a result, the signal quality of the received signal also changes. The demodulation circuit 62 measures the BER of such a received signal and inputs it to the first register 142.

  Here, the noise cancellation control unit 72 compares the BER of the received signal stored in the first register 142 with the BER of the received signal stored in the second register 143 (step S303). The BER stored in the first register 142 is the BER of the received signal when the phase setting value set in step S301 (that is, the phase setting value at the previous processing + Y) is applied to the noise cancellation signal. . On the other hand, the BER stored in the second register 143 is the BER of the received signal when the phase setting value at the previous processing (for example, the initial value of the phase setting value at the time of the first processing) is applied.

  When the BER stored in the first register 142 is lower than the BER stored in the second register 143 (step S303: Yes), the noise cancellation control unit 72 receives the received signal when the newly set phase adjustment value is applied. The BER stored in the first register 142 indicating the signal quality is stored in the second register 143 (step S304).

  On the other hand, when the BER stored in the first register 142 is equal to or higher than the BER stored in the second register 143 (step S303: No), the noise cancellation control unit 72 determines the phase adjustment value at the previous processing. Then, a value obtained by subtracting the predetermined phase value Y is set as a new phase adjustment value (step S305). Then, the value of the phase adjustment value register 147 is updated by applying the newly set phase setting value (step S306). As a result, the phase of the noise cancellation signal is changed, and a change occurs in the noise component that is removed from the reception signal that is synthesized with the noise cancellation signal. As a result, the signal quality of the received signal also changes. The demodulation circuit 62 measures the BER of such a received signal and inputs it to the first register 142. The noise cancellation control unit 72 stores the BER stored in the first register 142 indicating the signal quality of the received signal when the newly set phase adjustment value is applied, in the second register 143 (step S304).

  The first register 142 has the BER of the received signal when the newly set phase adjustment value is applied, and the second register 143 has the BER of the received signal when the phase adjustment value set at the previous processing is applied. Each is stored. By comparing these, it is possible to determine whether the signal quality of the received signal is improved or deteriorated when a predetermined phase value Y is added to or subtracted from the phase adjustment value. Therefore, according to the adjustment process of the phase adjustment value described with reference to FIG. 6, the phase adjustment value applied to the noise cancellation signal is received while receiving feedback from the demodulation circuit 62 that measures the BER of the received signal. Adjustment is performed by adding or subtracting a predetermined phase value Y.

  Returning to FIG. 4, the continuation of the process will be described. After the adjustment of the amplitude adjustment value (step S104) and the adjustment of the phase adjustment value (step S105) are completed, the noise cancellation control unit 72 stores the BER stored in the second register 143 and the determination value memory 145. Comparison with the determination BER is performed (step S106).

  When the BER of the received signal stored in the second register 143 is lower than the determination BER required to properly view the content transmitted by the received signal (step S106: Yes), the noise cancellation control unit 72 Then, the amplitude adjustment value and the phase adjustment value set at this time are set as the respective final adjustment values, and the operation ends.

  On the other hand, when the BER of the received signal stored in the second register 143 is equal to or higher than the determination BER (step S106: No), the noise cancellation control unit 72 determines the BER of the received signal stored in the second register 143. Until the value falls below the determination BER, the amplitude adjustment value and the phase adjustment value are repeatedly adjusted (steps S103 to S105).

  As described above, according to the operation described above, the noise cancellation signal received by the auxiliary antenna 110 receives the feedback of the signal quality of the reception signal obtained by synthesizing the noise cancellation signal, and the reception signal has the desired signal quality. The amplitude and phase are adjusted so that At this time, the amplitude and phase of the noise cancellation signal are preferably adjusted so as to have the same amplitude opposite to the noise component included in the received signal.

  Since the noise cancellation signal in the present embodiment is a signal based on a noise component captured inside the shield unit 90, it does not include a non-noise component or other noise component included in the reception signal. For this reason, noise components can be removed without affecting the signal quality of the received signal. For such a noise cancellation signal, the amplitude and phase are further adjusted according to the signal quality of the received signal, so that the noise component caused by the operation of the circuit inside the mobile terminal 1 is further reduced from the received signal. It can be removed with high accuracy.

  In the above-described example, BER is used as an example of an index indicating the signal quality of the received signal. However, the present invention is not limited to this mode, and any indicator that can adjust at least one of the amplitude and phase of the noise cancellation signal while appropriately monitoring the signal quality of the reception signal is an indicator that indicates the signal quality of the reception signal. May be used as

(3) First Modification A first modification of the disclosed wireless communication terminal and its operation will be described with reference to FIG. FIG. 7 is a block diagram illustrating an example of a configuration of a mobile terminal 1a that is an example of the disclosed wireless communication terminal and has a data broadcast reception and display function.

  As illustrated in FIG. 7, the mobile terminal 1 a includes a memory 150 in addition to the configuration of the mobile terminal 1. Although FIG. 7 shows an example in which the memory 150 is arranged outside the shield unit 90, the memory 150 may be arranged inside the shield unit 90. In FIG. 7, the same components as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

  The memory 150 is an information recording device such as a register that stores the control signal from the noise cancellation control unit 72 and can input the stored contents to the amplitude adjustment unit 120 and the phase adjustment unit 130.

  In the first modification, the noise cancellation control unit 72 is connected to the demodulation circuit 62, receives the signal quality of the received signal, and is connected to the tuner 71. When the data broadcast content selected by the user (in other words, the data broadcast channel) is switched, the tuner 71 notifies the noise cancellation control unit 72 that the content has changed.

  Based on the signal quality of the received signal input from the demodulation circuit 62, the noise cancellation control unit 72 appropriately sends the amplitude and phase adjustment values of the noise cancellation signal to the amplitude adjustment unit 120 and the phase adjustment unit 130 via the memory 150. input. When the signal quality of the received signal input from the demodulation circuit 62 converges to a desired quality set in advance, the noise cancellation control unit 72 self-stops the operation after inputting the adjustment value to the memory 150.

  Thereafter, the noise cancellation control unit 72 restarts the operation triggered by receiving a notification from the tuner 61 when the data broadcast content selected by the user is changed. The noise cancellation control unit 72 calculates the amplitude and phase of the noise cancellation signal according to the channel of the received signal after the change, and inputs it to the memory 150.

  After the signal quality of the received signal converges to a desired value and the final adjustment values of the amplitude and phase of the noise cancellation signal at that time are stored in the memory 150, it is stable by continuing to use the same noise cancellation signal. The signal quality can be maintained. At this time, the noise cancellation control unit 72 can continue to remove an appropriate noise component even if the operation is stopped. Using this, in the mobile terminal 1a of the first modification, after the signal quality of the received signal is stabilized, the operation of calculating the amplitude and phase of the noise cancellation signal is stopped. This leads to a reduction in power consumption in the entire portable terminal 1a, which is beneficial.

  In addition, when it is predicted that the signal quality of the received signal will greatly change due to the change of the reception channel of the content, the noise cancellation control unit 72 responds to the notification from the tuner 61. Resumes operation of amplitude and phase. For this reason, it is possible to continuously remove noise components from the received signal in accordance with such channel changes.

(4) Second Modified Example With reference to FIG. 8, a second modified example of the disclosed wireless communication terminal and its operation will be described. FIG. 8 is a block diagram illustrating an example of a configuration of a mobile terminal 1b that is an example of the disclosed wireless communication terminal and that has a data broadcast reception and display function.

  As shown in FIG. 8, the mobile terminal 1b includes a power control unit 160 in addition to the configuration of the mobile terminal 1a shown in FIG. In portable terminal 1b, power supply control unit 160 is connected to tuner 61 and receives notification of switching of data broadcast content from tuner 61. Although FIG. 8 shows an example in which the power supply control 160 is arranged outside the shield unit 90, the power supply control unit 160 may be arranged inside the shield unit 90. In FIG. 8, the same components as those in FIG. 1 or FIG. 6 are denoted by the same reference numerals and description thereof is omitted.

  The power supply control unit 160 is configured to control the mode of power supply from the battery (not shown) of the mobile terminal 1b to the noise cancellation control unit 72. For example, the power supply control unit 160 roughly switches the mode of power supply from the battery to the noise cancellation control unit 72 between two different modes. In the first mode, the power control unit 160 has sufficient power to perform feedback adjustment of the amplitude adjustment value and the phase adjustment value for the noise cancellation signal, such as calculation operation and signal input / output in the noise cancellation control unit 72. Supply. In the second mode, the power supply control unit 160 supplies a relatively small amount of power to the noise cancellation control unit 72 or stops the supply of power to the first mode.

  The power control unit 160 converges the signal quality of the received signal notified from the demodulation circuit 62 to a desired value, and the noise cancellation control unit 72 stores the final value after adjusting the amplitude adjustment value and the phase adjustment value in the memory 150. After that, the mode of power supply to the noise cancellation control unit 72 is switched from the first mode to the second mode. In addition, when the power supply control unit 160 receives notification from the tuner 61 that the data broadcast content has changed while supplying power to the noise cancellation control unit 72 in the second mode, With the notification as a trigger, the power supply to the noise cancellation control unit 72 is switched to the first mode.

  According to such an operation, as in the first modification, the signal quality of the received signal converges to a desired value, and the final adjustment values of the amplitude and phase of the noise cancellation signal at that time are stored in the memory 150. After that, by reducing the amount of power supplied to the noise cancellation control unit 72, it is possible to reduce power consumption in the entire mobile terminal 1b.

  In addition, when it is predicted that the signal quality of the received signal will greatly change due to the change of the reception channel of the content, the power supply control unit 160 changes the power supply mode according to the notification from the tuner 61. Change to the first mode for normal operation. For this reason, the noise cancellation control part 72 can restart the operation | movement which adjusts the adjustment value of the amplitude and phase of a noise cancellation signal according to the change of the receiving channel etc. of a content.

(5) Third Modification With reference to FIG. 9, a third modification of the disclosed wireless communication terminal and its operation will be described. FIG. 9 is a block diagram illustrating an example of a configuration of a mobile terminal 1c that is an example of the disclosed wireless communication terminal and that has a data broadcast reception and display function.

  The mobile terminal 1 described above removes noise components from the received signal by synthesizing a noise cancellation signal with a radio signal (that is, a received signal) received by the one-segment antenna 10. On the other hand, the mobile terminal 1c of the third modification removes the noise component from the received signal by synthesizing a noise cancellation signal with the radio signal (that is, the received signal) received by the mobile communication antenna 106. Yes.

  The mobile terminal 1c according to the third modified example is different from the mobile terminal 1 described above in that the modem 60 is replaced with an orthogonal demodulation unit 170. In FIG. 9, the same components as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted. However, the matching unit 20, the filter 30 and the amplification unit 40 in FIG. 9 connected to the mobile communication antenna 106 are different from the matching unit 20, the filter 30 and the amplification unit 40 in FIG. 1 connected to the one-segment antenna 10. These circuits may be prepared or shared. Other circuits similar to the circuits included in the mobile terminal 1 of FIG. 1 may be prepared as separate circuits or shared.

  The orthogonal demodulation unit 170 converts the received signal into a baseband signal, converts the baseband signal into a digital signal, and inputs the digital signal to the signal processing unit 71 and the noise cancellation control unit 72. The signal processing unit 71 performs necessary signal processing on the digital signal input from the quadrature demodulation unit 170, so that the digital signal can be output as voice, mail can be output, Internet can be displayed, etc. Is converted to

  Further, the orthogonal demodulator 170 monitors the signal quality of the received signal in the same manner as the demodulation circuit 62 described above. As a result, the noise cancellation control unit 72 appropriately adjusts the amplitude and phase of the noise cancellation signal in the above-described manner.

  According to the mobile terminal 1c of the third modification described above, noise components can be removed from the radio signal (that is, the received signal) received by the mobile communication antenna 106.

  The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the scope or spirit of the invention that can be read from the claims and the entire specification. Signal processing circuits and the like are also included in the technical scope of the present invention.

1 wireless communication terminal,
10 One-seg antenna
20 alignment section,
30 filters,
40 amplification section,
50 Noise canceling part,
61 Tuner,
62 demodulation circuit,
70 MPU
71 signal processing unit,
72 Noise cancellation control unit 110 Auxiliary antenna,
120 amplitude adjustment unit,
130 Phase adjustment unit.

Claims (5)

A first antenna for receiving a first radio signal;
A demodulator that demodulates the radio signal into a digital signal;
A processor for performing processing based on the digital signal;
A shield that electromagnetically shields the processor from the outside;
A second antenna provided inside the shield part;
A wireless communication terminal comprising: a noise canceling unit that removes a predetermined signal component based on a second wireless signal received by the second antenna from the first wireless signal. A signal quality monitoring unit for monitoring the signal quality of the first radio signal;
An adjustment unit that adjusts at least one of an amplitude and a phase of the second radio signal based on a predetermined adjustment value; and
The processor sets the predetermined adjustment value according to the signal quality of the first radio signal,
The noise cancellation unit synthesizes the second radio signal having at least one of amplitude and phase adjusted by the adjustment unit with the first radio signal, thereby generating the predetermined signal from the first radio signal. The wireless communication terminal according to claim 1, wherein a component is removed. A tuner for generating content data corresponding to the selected channel from the first radio signal;
A memory for storing the adjustment value set by the processor;
The processor (i) stops the adjustment value setting operation after storing the corresponding adjustment value in the memory when the signal quality of the first radio signal becomes a predetermined value, and (ii) 3. The wireless communication terminal according to claim 2, wherein the adjustment value setting operation is resumed in the tuner when a change occurs in the selected channel.   (i) supplying power to the processor with a predetermined first power amount; and (ii) when the signal quality of the first radio signal becomes the predetermined value, the processor sets the corresponding adjustment value to the processor. After storing in the memory, the amount of power supplied to the processor is changed to a second amount of power that is relatively lower than the first amount of power, and (iii) a change occurs in the selected channel in the tuner The wireless communication terminal according to claim 3, further comprising: a power control unit that changes an amount of power supplied to the processor to the first amount of power when the processor is connected. A demodulator that demodulates the first radio signal received by the first antenna into a digital signal;
A processor for performing processing based on the digital signal;
A shield that electromagnetically shields the processor from the outside;
A second antenna provided inside the shield part;
A signal processing circuit comprising: a noise cancellation unit that removes a predetermined signal component based on a second radio signal received by the second antenna from the first radio signal.

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