JP2010056838A - High-frequency receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce power consumption at a time, when segment receptions are to be changed over, from a 1 segment reception to a 12 segment reception. <P>SOLUTION: A C/N detector 85b, capable of detecting the quality of a reception at reception of a digital broadcasting signal, is mounted. An M-segment signal is brought into a state of a diversity reception by using tuners 27 and 29 from the state singly receiving an N-segment signal (N is a natural number, N<M) in the digital broadcasting signal by the tuner 27 on the basis of a reception-quality signal, when a signal constituted of an M segment (M is a natural number) in the digital broadcasting signal is singly received intermittently by the tuner 29. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a high frequency receiving apparatus capable of diversity reception.

  Hereinafter, a conventional high-frequency receiving device will be described with reference to FIG. In FIG. 5, the high frequency receiving apparatus 1 includes a high frequency receiving unit 2 and a diversity unit 3 connected to the high frequency receiving unit 2.

  The high-frequency receiving unit 2 includes tuner units 6 and 7 to which digital broadcast signals from antennas 4 and 5 are input, respectively.

  The diversity unit 3 includes a diversity circuit 8 to which the demodulated signals output from the tuner units 6 and 7 are supplied, an error correction circuit 9 and 10 to which the output of the diversity circuit 8 is supplied, and the error From the output terminals 12 and 13 to which TS (transport stream) signals output from the correction circuits 9 and 10 are respectively supplied, and from the C / N detector 15 from which the C / N signal output from the diversity circuit 8 is detected. It is configured.

  Furthermore, a system control unit 17 is connected to the high frequency receiving unit 2 and the diversity unit 3.

  About the high frequency receiver 1 comprised as mentioned above, the operation | movement is demonstrated below. Digital broadcast signals input from the antennas 4 and 5 are supplied to the tuner units 6 and 7, selected by the system control unit 17, and further demodulated signals are input to the diversity circuit 8.

  The demodulated signals respectively output from the diversity circuit 8 are supplied to error correction circuits 9 and 10. Further, the reception quality of the C / N signal output from the diversity circuit 8 is detected by the C / N detector 15.

  The system control unit 17 to which this reception quality signal is input controls the high frequency reception unit 2 and the diversity circuit 8 to select single reception or diversity reception.

  For example, when the reception quality is lower than a predetermined level due to fading due to mobile reception, the conventional high-frequency receiving apparatus 1 performs diversity reception in which a signal is received using the tuner unit 6 and the tuner unit 7, and the reception quality is low. When stable and better than a predetermined level, single reception is performed using either the tuner unit 6 or the tuner unit 7. As a result, high sensitivity can be ensured even when the reception state is poor due to mobile reception, and power consumption can be reduced when the reception state is good.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2001-156738 A

  In such a conventional high-frequency receiving device 1, for example, in the case of Japanese terrestrial digital broadcasting (ISDB-T), the tuner unit 6 receives a 13-segment signal, and the diversity unit 3 receives 1-segment and 12-segment signals. Separated and decrypted each.

  The reception quality is detected by the C / N detector 15 to which the C / N signal output from the diversity circuit 8 constituting the diversity unit 3 is input. When the reception quality is good, a high-quality 12-segment display is provided. When the reception quality deteriorates, switching to one segment with low image quality is performed.

  However, the 12-segment signal has a wider band and a larger transmission amount than the 1-segment signal. For this reason, power consumption of about 3.3 times is required in the case of receiving a 12-segment signal compared to the case of receiving a 1-segment signal. Therefore, power consumption when switching from 1-segment reception to 12-segment reception has become a problem in portable terminals driven by batteries.

  Accordingly, the present invention solves such a problem and aims to reduce power consumption when switching from 1-segment reception to 12-segment reception.

  In order to achieve this object, the high frequency receiver of the present invention is provided with a reception quality detector capable of detecting a reception quality signal at the time of reception of a digital broadcast signal. M is an N segment signal (N is a natural number, N <M) of the digital broadcast signal by the first tuner unit based on the reception quality signal intermittently single-received a signal composed of M is a natural number) From the single reception state, the M segment signal is set to a diversity reception state using the first and second tuner units.

  Thereby, the intended purpose can be achieved.

  As described above, the high-frequency receiving unit of the present invention includes a reception quality detector that can detect a reception quality signal at the time of receiving a digital broadcast signal, and the second tuner unit includes M segments (M is Based on the reception quality signal obtained by intermittently receiving a signal composed of a natural number), the first tuner unit receives a single N segment signal (N is a natural number, N <M) of the digital broadcast signal. In this state, the M segment signal is set to a diversity reception state using the first and second tuner units.

  This makes it possible to reduce power consumption when switching from 1-segment reception to 12-segment reception.

(Embodiment 1)
FIG. 1 is a block diagram of a high frequency receiving apparatus 21 according to Embodiment 1 of the present invention. In FIG. 1, the high-frequency receiving device 21 includes a high-frequency receiving unit 23, a diversity unit 25, and a system control unit 26.

  The high frequency receiving unit 23 is provided with tuner units 27 and 29, and an AGC voltage detector 31 connected between the tuner units 27 and 29.

  The tuner unit 27 includes an amplifier 39, a mixer 41, a filter 43, an amplifier 45, an A / D converter 47, a filter 49, and a demodulator 51 in order from the input terminal 35 to which the antenna 33 is connected to the output terminal 37. Is provided. The output of the oscillator 53 is connected to the other input of the mixer 41.

  Further, a C / N detector 51a for comparing the C / N signal output from the demodulator 51 with a predetermined reference value is provided.

  Further, a gain controller 55 for outputting a first AGC (automatic gain control) voltage is connected between the output of the mixer 41 and the gain control input 39 a provided in the amplifier 39. And a gain controller 57 for outputting a second AGC voltage is connected between the first input and the gain control input 45 a provided in the amplifier 45.

  Similarly, the tuner unit 29 has an amplifier 65, a mixer 67, a filter 69, an amplifier 71, an A / D converter 73, a filter 75, a demodulator in order from the input terminal 61 to which the antenna 59 is connected to the output terminal 63. A vessel 77 is provided. The output of the oscillator 79 is connected to the other input of the mixer 67.

  Further, a C / N detector 77a for comparing the C / N signal output from the demodulator 77 with a predetermined reference value is provided.

  Further, a gain controller 81 for outputting a third AGC voltage is connected between the output of the mixer 67 and the gain control input 65 a provided in the amplifier 65, and provided in the input of the demodulator 77 and the amplifier 71. A gain controller 83 that outputs a fourth AGC voltage is connected between the gain control inputs 71a.

  The first to fourth AGC voltages output from the gain controllers 55, 57, 81, and 83 are connected to the inputs 31a, 31b, 31c, and 31d of the AGC voltage detector 31, respectively. A reception quality detection signal is output from the 31 output 31e.

  Next, the diversity unit 25 includes input terminals 86a and 86b to which the output terminals 37 and 63 are connected, a subcarrier detector 84 connected between the input terminals 86a and 86b, and the input terminals 86a and 86b, respectively. The subcarrier selector / combiner 85 to which the signals are respectively supplied, the error correction circuits 87 and 89 to which the output signals from the subcarrier selector / synthesizer 85 are respectively supplied, and the TS signals from the error correction circuits 87 and 89 are supplied. Are output terminals 25a and 25b, and BER detectors 91 and 92 for comparing the BER signals output from the error correction circuits 87 and 89 with a predetermined reference value, respectively.

  The subcarrier detector 84 and the subcarrier selector / synthesizer 85 constitute a diversity circuit 86.

  Further, the system controller 26 has inputs 26a and 26b to which detection signals from the BER detectors 91 and 92 are input, an input 26c to which a detection signal from the AGC voltage detector 31 is input, and a subcarrier selection. An input 26d to which a reception quality signal from the synthesizer 85 is input, an output 26e to which a control signal for the subcarrier selection / synthesizer 85 is output, an output 26f to which a control signal for the high frequency receiver 23 is output, 26g and 26h to which C / N detection signals output from the C / N detectors 51a and 77a, respectively, are input are provided.

  Single reception and diversity reception by the high-frequency receiver 21 configured as described above will be described.

  For example, the tuner unit 27, the error correction circuit 87, and the C / N detector 85b are used when receiving a single segment signal, and the tuner unit 29 and the error correction circuit 89 are used when receiving a single segment signal, for example. In the case of using the C / N detector 85b to receive diversity of 1 segment signal or 13 segment signal, for example, the tuner units 27 and 29, the error correction circuit 87, and the C / N detector 85b are used.

  Further, as reception quality detectors, C / N signals for detecting C / N signals output from BER detectors 91 and 92 for detecting BER signals output from error correction circuits 87 and 89, and demodulators 51 and 77, respectively. Detectors 51a and 77a, a C / N detector 85b for detecting a C / N signal output from the subcarrier selector / synthesizer 85, and AGC voltage detection using first to fourth AGC (automatic gain control) voltages. The reception quality can be detected using at least one of the units 31.

  Note that the power consumption of the tuner unit 27 and the tuner unit 29 is different when the high-frequency receiving unit 23 receives a 1-segment signal and a 12-segment signal. In the reception of this one segment signal, since the reception band is narrower than the reception of the 12 segment signal, the filter 43 of the tuner unit 27 and the filter 69 of the tuner unit 29 can reduce the order of the filter, and the A / D converter 47, The sampling frequency of 73 can be lowered. Thus, the power consumption can be further reduced in the reception of the 1-segment signal compared to the reception of the 12-segment signal.

  Next, the operation of each reception mode when, for example, the C / N detector 85b is used as the reception quality detector will be described using (Table 1).

  Mode A (diversity reception of one segment) is a case where the one segment signal is diversity-received by the tuner units 27 and 29.

  In this mode A (1 segment is received by diversity), for example, reception quality can be ensured by diversity reception of 1 segment signal when C / N is 5 dB or more, and the power consumption of the high frequency receiver 23 is 100 mW, for example. When converted to single reception, the required C / N is 2 dB or more.

  Mode B (single segment single reception) is a case where the tuner unit 27 receives a single segment signal as a single reception.

  In this mode B (single segment single reception), a single segment signal can be single-received when the C / N is 5 dB or more, and the power consumption of the high frequency receiver 23 is 60 mW.

  Mode C (12 segments intermittently single received) is a case where the tuner unit 29 intermittently receives 12 segment signals.

  In this mode C (12 segments are intermittently received in single), when C / N is 17 dB or more, it is possible to shift from mode B (single segment as single reception) to mode D (12 segments as diver reception).

  The power consumption in this mode C (single reception of 12 segments intermittently) is intermittently 1/10 of the operating time of the tuner unit 29 with respect to the power consumption of 200 mW in mode E (single reception of 12 segments). When operated, the power consumption can be reduced to 20 mW.

  Mode D (diversity reception of 12 segments) is a case where 12 segment signals are diversity-received by the tuner units 27 and 29.

  In this mode D (12 segments receive diversity), 12 segment signals can be diversity received when the C / N is 20 dB or more, and the power consumption of the high frequency receiver 23 is 350 mW. When converted to single reception, the required C / N is 17 dB or more.

  Mode E (single reception of 12 segments) is a case where the tuner unit 29 performs single reception of 12 segment signals.

  In this mode E (12 segments are single-received), 12-segment signals can be single-received when the C / N is 20 dB or more, and the power consumption of the high-frequency receiver 23 is 200 mW.

  Next, as a representative example in (Table 1), specific operations in mode A (one segment is received by diver) and mode B (one segment is received by single) will be described below.

  First, mode A (diver reception for one segment) will be described. The high-frequency receiving device 21 is set to receive in mode A (one segment is received by a diver) by control signals from the outputs 26e and 26f of the system control unit 26.

  The digital broadcast signal input from the antenna 33 is input to the amplifier 39 via the input terminal 35 of the tuner unit 27. In the amplifier 39, gain control is performed by the gain controller 55 so that the output level of the mixer 41 becomes a constant level.

  The input to the gain controller 55 may be connected to the output of the filter 43 instead of connecting the output of the mixer 41. In this case, since the interference signal is suppressed by the filter 43, the amplifier 39 is less affected by the interference signal because the influence of the interference signal is suppressed and gain control is performed.

  Both the output signal from the amplifier 39 and the output of the oscillator 53 are input to the mixer 41. The output signal from the mixer 41 is suppressed by the filter 43. An output signal from the filter 43 is input to the amplifier 45.

  The amplifier 45 is gain-controlled by a gain controller 57 so that the input signal level to the demodulator 51 is constant.

  Further, the output signal from the amplifier 45 is converted from an analog signal to a digital signal by the A / D converter 47. In this digital signal, the interference signal is sufficiently suppressed by the filter 49, and only the desired signal is output. The output signal of the filter 49 is demodulated by the demodulator 51. The demodulated signal output from the demodulator 51 is output from the output terminal 37.

  Similarly, the digital broadcast signal input from the antenna 59 is input to the amplifier 65 via the input terminal 61 of the tuner unit 29. In the amplifier 65, gain control is performed by the gain controller 81 so that the output level of the mixer 67 becomes a constant level. Note that the input signal to the gain controller 81 may supply the output of the filter 69 instead of the output of the mixer 67.

  Both the output signal from the amplifier 65 and the output of the oscillator 79 are input to the mixer 67. The output signal from the mixer 67 is suppressed by the filter 69. An output signal from the filter 69 is input to the amplifier 71.

  The gain of the amplifier 71 is controlled by a gain controller 83 so that the input signal level to the demodulator 77 is constant.

  Further, the output signal from the amplifier 71 is converted from an analog signal to a digital signal by the A / D converter 73. This digital signal has its interference signal suppressed by the filter 75. The output signal of the filter 75 is demodulated by the demodulator 77. The demodulated signal output from the demodulator 77 is output from the output terminal 63.

  The demodulated signals output from these output terminals 37 and 63 are input to input terminals 86a and 86b of the diversity circuit 86, respectively.

  The subcarrier detector 84 connected to the input terminals 86a and 86b detects the signal quality of the subcarriers included in the two demodulated signals. Based on the detected signal quality information, a weighting coefficient for each subcarrier is calculated. This weighting coefficient is input from the output 84 a of the subcarrier detector 84 to the input terminal 85 a of the subcarrier selector / synthesizer 85.

  In this subcarrier selector / combiner 85, each subcarrier is multiplied by a weighting coefficient, and the combined subcarrier combined signal is output from, for example, the output terminal 86c. The signal synthesized in this way is improved C / N by a maximum of 2 times by the weighting coefficient.

  The subcarrier composite signal is input to the error correction circuit 87, and the error-corrected TS signal is output from the output terminal 25a. The error correction circuit 87 performs error correction.

  Further, the reception quality signal of the subcarrier signal included in the demodulated signal is detected from the output 84b of the subcarrier detector 84. The detected reception quality signal is input to the input 26j of the system control unit 26.

  Next, mode B (single reception of one segment) will be described. The high-frequency receiving device 21 is set to receive mode B (single reception of one segment) by control signals from the outputs 26e and 26f of the system control unit 26.

  In single reception, for example, the tuner unit 27 is in an operating state and the tuner unit 29 is in a non-operating state.

  The operation from diversity reception to single reception is controlled by control signals from the outputs 26e and 26f of the system control unit 26. For example, one tuner unit 29 is changed from an operating state to a non-operating state, and the other tuner unit 27 is It is in an operating state.

  Thus, the demodulated signal output from the tuner unit 27 is input to the input terminal 86a of the system control unit 26. On the other hand, the demodulated signal is not input from the input terminal 86b.

  The output signal from the output terminal 86c of the diversity circuit 86 is input to the error correction circuit 87, and the error-corrected TS signal is output from the output terminal 25a.

  In this way, it is possible to set mode A (1 segment for diver reception) and mode B (1 segment for single reception). The same applies to Mode D (diversity reception of 12 segments) and Mode E (single reception of 12 segments).

  FIG. 2 is a flowchart corresponding to these modes A to E. In particular, as shown by a portion 200 surrounded by a dotted line, the feature of the present application is a mode in the middle of a transition from mode B (single segment single reception), step 205, to mode D (12 segments diver reception), step 213. C (12 segments are intermittently single-received).

  When the reception quality signal such as the C / N detection signal in this mode C (intermittently receiving 12 segments) is good, from mode B (single segment receiving single) to mode D (dividing 12 segments) To do.

  In FIG. 2, in step 201, the mode A (one segment is received by diversity) is selected, and the tuner units 27 and 29 receive the one segment signal at diversity. After step 201, the process proceeds to step 203.

  In this step 203, the reception quality in the mode A (1 segment is received by the diver) is detected by the C / N detector 85b, the determination result NG1 (C / N <5 dB), the determination result OK1 (5 dB ≦ C / N <8). ), If the determination result is OK2 (8 dB ≦ C / N), the process proceeds to steps 201, 203, and 205, respectively.

  In this step 205, mode B (single segment is received as single) is set, and the tuner unit 27 sets the single segment signal as single received. After step 205, step 207 is performed.

  In step 207, the reception quality in mode B is detected by the C / N detector 85b. When the determination result is NG2 (C / N <5 dB) and determination result OK3 (5 dB ≦ C / N), the process proceeds to step 201 and step 209, respectively.

  In this step 209, in addition to the mode B (single reception of one segment), the mode C (12 segments is intermittently single reception) is selected, the tuner unit 27 performs single reception of a single segment signal, and the tuner unit 29 performs 12 segments. The signal is intermittently single received.

  That is, the tuner unit 29 is intermittently received, and C / N in the 12 segment signal is detected. For example, if the operation time of the tuner unit 29 in mode C (intermittently receives 12 segments) is 1/10, as is clear from (Table 1), consumption of mode E (single segments receive 12) Electric power 200 mW can be set to 20 mW. After step 209, the process proceeds to step 211.

  In step 211, the reception quality in mode C is detected by the C / N detector 85b. In the case of the determination result NG3 (C / N <5 dB), the determination result OK4 (5 dB ≦ C / N <17 dB), and the determination result OK5 (17 dB ≦ C / N) as the detection results, step 201, step 211, The process proceeds to step 213 respectively. If the determination result is NG3 (C / N <5), step 207 may be used.

  In step 213, mode D (12 segments are received by diversity), and 12 segments signals are received by the tuner units 27 and 29 as diversity reception. After step 213, the process proceeds to step 215.

  In step 215, the reception quality in mode D (12 segments are received by the diver) is detected by the C / N detector 85b. As the detection result, in the case of the determination result NG4 (C / N <20 dB), the determination result OK6 (20 dB ≦ C / N <23 dB), and the determination result OK7 (23 dB ≦ C / N), step 201 and step 215 , The process proceeds to step 217, respectively. If the determination result is NG4 (C / N <20), step 205 may be used.

  In this step 217, mode E (12 segments are single-received) is set, and the tuner unit 29 sets the 12-segment signal to single-receive. After step 217, the process proceeds to step 219.

  In step 219, the reception quality in mode E (single reception of 12 segments) is detected by the C / N detector 85b. In the case of the determination result NG5 (C / N <17 dB), the determination result OK8 (17 dB ≦ C / N <20 dB), and the determination result OK9 (20 dB ≦ C / N) as the detection results, step 201, step 213, The process proceeds to step 219. If the determination result is NG5 (C / N <17), step 205 may be used.

  In this way, the C / N detector 85b can compare and detect the C / N value output from the subcarrier selector / synthesizer 85 with a predetermined reference value of C / N, thereby receiving the signal. Quality can be detected.

  When shifting from mode B (single segment single reception) in step 211 to mode D (12 segments receive diver) in step 213, diversity reception of 12 segment signals is performed in mode D (12 segments receive diversity). Until the 12-segment signal is ready for image display, the 1-segment signal is displayed as an image in Mode B (single reception of one segment). As a result, image disturbance during mode switching can be eliminated.

  In this embodiment, mode D in step 213 (diversity reception of 12 segments) is changed from mode B in step 205 (single reception of one segment) to mode E in step 217 (single reception of 12 segments). If there is a reception quality detection result in step 211 where C / N ≧ 20 dB, the mode directly shifts from mode B in step 205 (single reception of one segment) to mode E in step 217 (single reception of 12 segments). You may do it. By shifting in this way, the power consumption of the high-frequency receiving device 21 can be further reduced.

  As described above, the C / N detector 85b is used as the reception quality detector and the mode A to the mode E are switched. However, the C / N detectors 51a and 77a can be used at the time of single reception.

  Further, BER detectors 91 and 92 can be used instead of the C / N detector 85b as the reception quality detector. The BER detectors 91 and 92 require detection time with respect to the C / N detectors 51a, 77a, and 85b, but the detection accuracy of the reception quality is more excellent.

  Furthermore, the AGC voltage detector 31 can be used as a reception quality detector instead of the C / N detector 85b. The AGC voltage detector 31 can detect the reception quality in a short time with respect to the C / N detectors 51a, 77a, and 85b. Therefore, when the moving speed is high, the reception quality can be detected by the AGC voltage detector 31.

  Step 206 (not shown) for detecting reception quality by the AGC voltage detector 31 may be newly provided between step 205 and step 207.

  Furthermore, since the subcarrier detector 84 can detect the reliability information according to C / N of each subcarrier or C / N, for example, switching is not performed when the quality of a specific carrier is poor. It is possible to set in detail. This makes it possible to prevent incorrect switching.

  Next, a specific operation when the AGC voltage detector 31 is used will be described below.

  FIG. 3A is a characteristic diagram of the AGC voltage 301 of the amplifier 39 when only a desired signal is input. The AGC voltage 301 is input to the input 31 a of the AGC voltage detector 31.

  The horizontal axis 302 represents the input signal level to the input terminal 35, and the vertical axis 303 represents the voltage.

  Further, the level 302a is set to about −100 dBm, the level 302b is set to about −50 dBm, and the level 302c is set to about 0 dBm. The AGC voltage 301 has an upper limit voltage 303a that is a minimum gain and a lower limit voltage 303b that is a maximum gain.

  Further, the AGC voltage 301 includes an AGC voltage 301a and an AGC voltage 301b.

  This AGC voltage 301a is an AGC voltage with respect to the input signal level from the weak electric field of the level 302a (−100 dBm) to the level 302b (−50 dBm) to the intermediate electric field. The amplifier 45 is set to the maximum gain, and the input level to the mixer 48 is Work so as not to lower.

  A maximum gain control range A is provided for this maximum gain. The maximum gain control range A is a region between the lower limit voltage 303b and the maximum gain determination voltage 303g provided in the vicinity of the lower limit voltage 303b. From this maximum gain control range A, it is possible to determine whether or not the AGC voltage 301 is in the maximum gain state.

  The AGC voltage 301b is an AGC voltage when an input signal having a strong strong electric field is input from the medium electric field of the level 302b (−50 dBm) to the level 302c (0 dBm), and the output level of the mixer 48 is set to a constant level. Control.

  FIG. 3B is a characteristic diagram of the AGC voltage 311 of the amplifier 45 when only a desired signal is input. The AGC voltage 311 includes an AGC voltage 311 a and an AGC voltage 311 b and is input to the AGC voltage detector 31.

  The upper limit voltage 303c and the lower limit voltage 303d represent the upper limit voltage and the lower limit voltage of the AGC voltage 311, respectively. The minimum gain control range B is a region between the upper limit voltage 303c and the minimum gain determination voltage 103h provided close to the upper limit voltage 303c. From this minimum gain control range B, it is possible to determine whether or not the AGC voltage 311 is in the minimum gain state.

  The AGC voltage 311a is an AGC voltage when an input signal level of a weak electric field to a medium electric field of level 302a (−100 dBm) to level 302b (−50 dBm) is input. Therefore, it works so as not to lower the input level to the demodulator 51.

  The AGC voltage 311b is an AGC voltage when an input signal level of a medium electric field to a strong electric field of the level 302b (−50 dBm) to the level 302c (0 dBm) is input. The amplifier 50 is set to the minimum gain by the AGC voltage 311b, and the input level to the demodulator 51 is controlled to a constant level.

  In this way, when only the desired signal is input to the input terminal 35, the AGC voltage 301 of the amplifier 39 becomes the maximum gain control range A at the input signal level of the weak electric field to the medium electric field, and further, the medium electric field to the strong electric field At the input signal level, the AGC voltage 311 of the amplifier 45 has a voltage in the minimum gain control range B.

  That is, one of the AGC voltage 301 and the AGC voltage 311 exists in the maximum gain control range A and the minimum gain control range B. Therefore, it is possible to detect the input signal level when only the desired signal is input by the AGC voltages 301 and 311. Here, the reception quality deteriorates when a desired signal having a weak electric field is input, and the input signal level is close to the level 302a.

  Next, the operation of the AGC voltage detector 31 when a desired signal and a received signal composed of a disturbing signal 25 dB larger than the desired signal are input will be described.

  FIG. 4A is a characteristic diagram of the AGC voltage 401 of the amplifier 39 with respect to the desired signal level. The AGC voltage 401 includes an AGC voltage 401a, an AGC voltage 401b, and an AGC voltage 401c.

  The AGC voltage 401a is an AGC voltage when a reception signal having a weak electric field of level 302a (−100 dBm) to level 302d (−75 dBm) is input. In this case, the interference signal is also −50 dBm or less and does not affect the gain control of the amplifier 39, so that the amplifier 45 has the maximum gain.

  The AGC voltage 401b is an AGC voltage when a reception signal having a medium electric field of level 302d (−75 dBm) to level 302e (−25 dBm) is input. In this case, since the interference signal is −50 dBm or more, the gain control of the amplifier 39 is performed according to the interference signal level.

  The AGC voltage 401c is an AGC voltage when a received signal having a strong electric field of level 302e (−25 dBm) to level 302c (0 dBm) is input. In this case, since the disturbing signal is 0 dBm or more, the amplifier 39 is set to the minimum gain.

  FIG. 4B is a characteristic diagram of the AGC voltage 411 of the amplifier 45 with respect to the received signal. The AGC voltage 411 includes an AGC voltage 411a, an AGC voltage 411b, and an AGC voltage 411c.

  The AGC voltage 411a is an AGC voltage when a reception signal having a weak electric field of level 302a (−100 dBm) to level 302d (−75 dBm) is input. In this case, the signal output from the amplifier 45 is input to the amplifier 50 via the filter 49. The signal input to the amplifier 50 is only the desired signal because the interference signal is suppressed by the filter 49. As a result, the AGC voltage 411a is subjected to gain control according to a desired signal level from the level 302a (−100 dBm) to the level 302d (−75 dBm).

  Next, the AGC voltage 411b is an AGC voltage when a reception signal in the vicinity of a middle electric field of the level 302d (−75 dBm) to the level 302e (−25 dBm) is input.

  In this case, the gain of the AGC voltage 401b is controlled in the amplifier 39 by an interference signal of −50 dBm or more. The amplifier 39 outputs a desired signal whose gain is controlled more than necessary by the interference signal and the interference signal.

  These signals are input to the filter 43 to suppress the interference signal, and only a desired signal having a small level is output from the filter 43. This small desired signal is amplified, and the AGC voltage 411b of the amplifier 45 has a constant gain control amount.

  Further, the AGC voltage 411c is an AGC voltage when a received signal having a strong electric field of level 302e (−25 dBm) to level 302c (0 dBm) is input. In this case, the disturbing signal becomes 0 dBm or more, and has a constant gain control amount as with the AGC voltage 411b.

  In this way, the AGC voltages 401b and 401c do not reach the maximum gain control range A and the AGC voltages 411b and 411c do not enter the minimum gain control range B at the level 302d (−75 dBm) or higher.

  Thus, using the AGC voltage detector 31 for comparing and detecting each AGC voltage, the reception quality is deteriorated in the weak electric field due to the desired signal, or the reception quality due to the large interference signal input together with the desired signal is improved. It can be detected whether it is deterioration. Each AGC voltage is detected by the AGC voltage even when the reception condition changes during mobile reception, and therefore the followability is very good.

  Therefore, for example, even during high-speed movement in which the reception state changes every moment, switching between single reception and diversity reception can be performed smoothly without impairing reception quality. In this embodiment, the AGC voltage is used as means for detecting reception quality. However, for example, when an amplifier whose gain is switched discretely is used, the AGC voltage is used as a digital signal as means for detecting reception quality. AGC register information (digital value) or the like may be used.

  As a result, the reception quality can be detected more accurately, and this digital signal can be signal-processed by, for example, an I2C bus line, so that signal processing can be performed by a common I2C bus line. Thereby, it becomes easy to integrate the semiconductor of an analog part and a digital part on one chip, and the high frequency receiver 21 can be reduced in size.

  As described above, when one tuner unit 27 is set to the reception state of mode B (single segment is received in single mode) and further shifted to the reception state of mode D (12 segments are received by diver), the one tuner unit 27 In addition to the reception of mode B (single reception of one segment), the other tuner unit 29 sets the reception state of mode C (intermittent single reception of 12 segments).

  C / N in the 12 segment signal can be detected by setting the other tuner unit 29 to mode C (12 segments intermittently single reception) and intermittently receiving 12 segment signals.

  Assuming that the operation time of the tuner unit 29 for intermittent single reception is 1/10, as is clear from Table 1, the power consumption in mode C (12 segments intermittently single reception) is as large as 20 mW. Can be reduced.

  That is, it can be reduced to 1/10 in mode C (single reception of 12 segments intermittently) with respect to power consumption of 200 mW in mode E (single reception of 12 segments).

  Although the partial segment signal has been described as a one-segment signal, the same applies to, for example, a three-segment signal.

  For example, the segment number of the partial segment signal is N (N is a natural number) and is an N segment signal, and a segment signal having a larger segment number than the N segment signal is an M segment (N <M, where M is a natural number).

  A mode C is provided in which the tuner unit 29 receiving a single segment of the M segment receives a single signal intermittently from the single segment receiving state of the N segment signal to the diversity receiving state of the M segment signal. As a result, power consumption can be reduced.

  Further, the tuner units 27 and 29 may be a plurality of tuner units, and output signals from the plurality of tuner units may be supplied to the diversity circuit 86, respectively. The reception quality can be further improved by selecting single reception or diversity reception by the plurality of tuner units.

  Since the high-frequency receiver of the present invention can smoothly switch from 1-segment reception to 12-segment reception with low power consumption, it can be applied to mobile portable devices and the like.

Block diagram of the high-frequency receiving device according to Embodiment 1 of the present invention Same as above, flowchart using modes A to E (A) The figure showing the first AGC voltage with respect to the desired signal level, (b) The figure showing the second AGC voltage with respect to the desired signal level. (A) The figure showing the first AGC voltage with respect to the received signal level, (b) The figure showing the second AGC voltage with respect to the received signal level. Block diagram of a conventional high frequency receiver

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 High frequency receiver 23 High frequency receiver 25 Diversity part 27 Tuner part 29 Tuner part 35 Input terminal 61 Input terminal 85b C / N detector

Claims (9)

First and second input terminals to which digital broadcast signals are respectively input, and connected to the first and second input terminals, respectively, receive channels are selected, and the first and second demodulated signals are selected. Receiving a digital broadcast signal, and a first and second tuner unit for outputting the first and second tuner units, and a diversity unit for receiving the first and second demodulated signals and performing signal processing for single reception or diversity reception, respectively. A reception quality detector capable of detecting a reception quality signal at the time, and the second tuner unit intermittently single-receiving a signal composed of M segments (M is a natural number) of the digital broadcast signal. Based on the reception quality signal, the first tuner unit generates an N segment signal (N is a natural number) of the digital broadcast signal. From the state where N <M) is received as a single signal, the M segment signal is received as a single signal using the first tuner unit or the second tuner unit, or using the first and second tuner units. A high-frequency receiving apparatus that makes the M segment signal in a state of diversity reception. 2. The M tuner signal is intermittently single-received by the second tuner unit based on the reception quality signal when the N-segment signal is single-received by the first tuner unit. High frequency receiver. The reception quality detection unit is supplied with the C / N signal output from the first or second tuner unit and is compared with a predetermined reference value to detect the reception quality. The high frequency receiver according to claim 1, wherein a C / N detector is used. The reception quality detection unit is provided with a second C / N detector that is supplied with the C / N signal output from the diversity unit and can detect the reception quality by being compared with a predetermined reference value. The high frequency receiver according to claim 1 to be used. The reception quality detection unit is supplied with a BER (bit error rate) signal output from the diversity unit and uses a BER detector capable of detecting reception quality by being compared with a predetermined reference value. Item 4. The high frequency receiving device according to Item 1. The high frequency receiving apparatus according to claim 1, wherein the reception quality detection unit uses a reception quality signal from a subcarrier detector. The second tuner unit includes a first amplifier having a first gain control input, a mixer, a first filter, and a second amplifier having a second gain control input in order from the input toward the output, A A first gain controller connected to the D / D converter, a second filter, and a demodulator, and connected between the output of the mixer and the first gain control input; and the input of the demodulator A second gain controller connected between the second gain control input and the second gain control input is provided, and the reception quality detection unit outputs the first and second output from the first and second gain controllers, respectively. 2. The high frequency receiver according to claim 1, wherein an AGC voltage detector that detects reception quality by using an AGC (automatic gain control) voltage is used. The high-frequency signal receiver according to claim 7, wherein the first and second gain control voltages output from the first and second gain controllers are converted into digital signals by respective DACs (digital analog converters). The high frequency receiving apparatus according to claim 1, wherein the first and second tuner units are a plurality of tuner units, and output signals from the plurality of tuner units are input to the diversity unit.

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