JP4996643B2 - Broadcast receiver - Google Patents

Description

  The present invention relates to a broadcast receiving apparatus, and more particularly to a broadcast receiving technique capable of satisfactorily receiving broadcast waves.

  For example, a method shown in FIG. 6 is known as a method of performing gain control in a broadcast receiving apparatus that receives broadcast waves by an antenna. FIG. 6 is a functional block diagram illustrating a partial configuration example centering on a tuner unit of a receiving apparatus including a general tuner. As shown in FIG. 6, the RF input obtained from the antenna 101 is output to the demodulation circuit via the preamplifier 110, BPF 111, RFVGA 112, mixer 113, BPF 115, and IF amplifier 116 of the tuner unit 108. The mixer 113 is provided with an oscillator (OSC) 114. The output from the IF amplifier 116 also enters the level detector 125 and is fed back to the RFVGA 112 via the voltage control means 126.

  A technique described in Patent Document 1 below is also known. In this technique, an antenna whose frequency tuning can be adjusted by a matching circuit, a high-frequency circuit that amplifies and frequency-converts a high-frequency signal received by the antenna, and a digital that converts an analog received signal output from the high-frequency circuit into a digital signal Generates an antenna gain control signal based on received signal power or amplitude information in a reception system including a processing unit and a CPU for controlling the frequency tuning of the antenna by supplying a tuning control signal to the matching circuit The gain control signal is added to the tuning control signal.

JP 2004-363854 A

  However, in the technique described in Patent Document 1, it is possible to receive a signal within a certain power range by a gain control signal, but measures are taken for a signal with very strong power or very weak power. Absent.

  An object of the present invention is to enable a receiving apparatus to receive signals well over a wide range (from weak power to strong power) of signal power.

  According to an aspect of the present invention, there is provided a television receiver having a signal power increase / decrease unit for amplifying and attenuating signal power input to a tuner between an antenna and a tuner, wherein the signal power increase / decrease unit is an amplifier. In the channel search, the switch is fixed to the side having more receivable channels on the amplification side and the attenuation side, and the receivable channels are the amplification side and the attenuation side. In the case where the number is the same, the television receiver is characterized in that the switch is fixed to the side having more receivable channels in which the reception state is dominant.

According to another aspect of the present invention, there is provided a television receiver having a signal power increasing / decreasing unit for amplifying and attenuating signal power input to a tuner between an antenna and a tuner, and an output signal from the tuner A reception state detection unit that detects AGC, C / N, and BER, and based on the detection result of the reception state detection unit, amplification or attenuation of the signal power in the signal power increase / decrease unit And a control unit that performs feedback control. The signal power increasing / decreasing unit includes a switch unit that switches between an amplifier (amplifier) and an attenuator (attenuator), and the control unit has weak power based on the AGC and at least one of the C / N and BER. It is preferable to switch the switch unit to the amplifier side to amplify the signal when the reception state based on the above is deteriorated and to attenuate the switch unit to the attenuator side when the power is strong. .

  In the channel search, a counter unit for counting the reception state information detected by the reception state detection unit on each of the attenuation side and the amplification side is provided, and based on the reception state information , It is determined whether each channel is normally receivable, and when it is determined that each channel is normally receivable, the counter on either the attenuation side or the amplification side is counted up to perform channel search. At the end, it is preferable to compare the counter values and fix the switch so that more channels can be received normally.

  After the channel search is completed, if the counter value for counting the receivable channels is the same number on the amplifier side and the attenuator side, the C / N when the receivable channel is set on the amplifier side Compare the value with the C / N value when set on the attenuator side, and provide a counter that counts the number of stations where the C / N value is dominant in each amplifier and attenuator, and set the counter value to the larger one Is preferred.

  The television receiver includes a first and a second tuner having at least two or more tuners, and has a configuration in which an amplifier and an attenuator are provided in a splitter unit that distributes a signal to the tuner. Also good.

  When performing a channel search, only when the amplification side determines that “normal reception is not possible” and it is determined that “not strong power” from the value of the AGC, the next is not switched to the attenuation side. It is preferable to proceed to this channel. Further, the channel search is performed on the amplification side, the reception state information is acquired in each channel, and if reception is possible normally, the amplifier-side counter is counted up, and it is determined that “normal reception is not possible”, and , A flag storage unit that stores a re-search flag that is set to “1” when it is determined that the power is higher than the value of AGC, and after the channel search is completed, the re-search flag in the flag storage unit If "1", the processing may be continued by switching to the amplification side.

  According to the present invention, there is an effect that a television receiver can receive a broadcast satisfactorily for signal power in a wide range (from weak power to strong power).

FIG. 1A is a diagram illustrating a configuration example of a broadcast receiving apparatus according to the first embodiment of the present invention. FIG. 1B is a diagram illustrating a configuration example of a double tuner type broadcast receiving apparatus. It is a flowchart figure which shows in detail the process which acquires the reception status information in each when it switches to each of Amp and ATT, searching one channel at a time. FIG. 3 is a flowchart showing a flow of processing based on an algorithm different from FIG. 2, that is, a second method for searching while acquiring information of Amp and ATT for each channel. FIG. 10 is a flowchart illustrating an example of a method of performing a search again on the ATT side when a “signal with strong power but cannot be received normally” is detected after performing an all-channel search on the Amp side. It is a figure which shows the electric power range which can be received in the receiver by this Embodiment. It is a functional block diagram which shows the example of a partial structure centering on the tuner part of the receiver including a general tuner.

Hereinafter, a broadcast receiving apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a diagram illustrating a configuration example of a broadcast receiving apparatus according to the first embodiment of the present invention. As shown in FIG. 1A, the broadcast receiving apparatus according to the present embodiment alternatively includes an antenna 1, a band pass filter BPF3, an attenuator ATT5, and an amplifier Amp7. Switch 9a, 9b that can be switched to, a tuner unit 8 that follows, an IF AGC 17 that receives the output from the tuner unit 8, an A / D converter 18, a demodulation circuit 19, and an error correction circuit (Forward Error Correction) An FEC 20 and an IF AGC circuit 27 that receives the AGC output from the demodulation circuit 19 are provided, and the output is IF IF
Feedback is provided to the AGC 17.

In the tuner unit 8, in order from the antenna 1 side, a preamplifier 10, a first band pass filter (Band Pass Filter) BPF 11, and a variable gain amplifier RF for RF (Radio Frequency).
A VGA 12, a mixer 13, a second band pass filter (Band Pass Filter) BPF 15, and an IF (Intermediate Frequency) amplifier 16 are provided, and an output thereof is input to the IF AGC 17. The output of the IF amplifier 16 is also connected to the voltage control means 26, and the output is fed back to the RFVGA 12. Here, in this embodiment, the AGC output from the IF AGC 27, the CN estimated by the demodulation circuit 19, and the bit error rate (BER) BER calculated from the FEC 20 are received state information detecting means. 31 to exchange data with the control means 32. The control means 32 is provided with a receivable counter 32a and a C / N superior counter 32b, and switches the selector switches 9a and 9b based on these counter values. Further, the counter value and the like can be stored in the storage means 33. Furthermore, the storage unit 33 can also store the reception state information from the reception state information detection unit 31.

For example, in the first channel search performed by installing the broadcast receiving apparatus, the reception state information (AGC, BER, C / N) is acquired by switching to the attenuator ATT5 side and the amplifier Amp7 side. A receivable counter 32a for counting the number of receivable channels in each of the amplifier Amp7 and the attenuator ATT5 is provided. Based on the reception state information from the reception state information detection unit 31, the video / It is determined whether or not the sound can be received. If it is determined that the sound can be normally received, the attenuator side or amplifier side counter is incremented by one. At the end of the channel search, the counters are compared and fixed so that more channels can be received normally. For example, counting is performed while scanning channels as follows.
13ch (Amp)-> 13ch (ATT)-> 14ch (Amp)-> 14ch (ATT)-> 15ch (Amp)-> 15ch (ATT)->

Further, in each channel that can be received by the amplifier Amp7 and the attenuator ATT5, a C / N superior counter 32b is provided for counting the higher one of the amplifier Amp7 and the attenuator ATT5, and the value of the receivable counter 32a is provided. If the number is the same, it is determined from the reception state information stored in the storage means which of the attenuation side and the amplification side the C / N is higher in each receivable channel. When it is determined that the C / N is higher, the C / N superior counter 32b on the attenuation side is counted up, and when it is determined that the C / N is higher on the amplification side, the C / N superior counter on the amplification side 32b is counted up, and the switch is fixed so that the C / N becomes higher in more channels.

(1) FIG. 2 is a flowchart showing in detail a process for acquiring reception state information when switching to Amp and ATT while searching one channel at a time, as an example of the above processing flow. It is. As shown in FIG. 2, first, a channel search is started in step S1, and in step S2, it is first switched to the Amp side. In this state, the frequency is set (tuned) to the tuner in step S3, and it is determined whether or not the tuning is successful in step S3 '. If successful (YES), the process proceeds to step S4. If unsuccessful (NO), the process proceeds to step S7.

In step S 4, reception state information (AGC, BER, C / N) is acquired and stored in the storage unit 33. Next, in step S5, it is determined whether normal reception is possible. For example, if C / N is 20 dB or more, or BER before Reed-Solomon correction after Viterbi decoding is 2.0 × 10 ⁻⁴ or less, it is determined that the reception state is normal. If it is determined that the signal can be normally received (Yes), the process proceeds to step S6, 1 is added to the Amp side receivable counter, and the process proceeds to step S7. In the case of NO, the process proceeds to step S7 and is switched to the ATT side.

  Next, a reception state acquisition process is performed in step S8, CN and BER are acquired and stored in the storage means 33. Based on these values, it is determined whether normal reception is possible in step S9. If the determination in step S9 is YES, 1 is added to the ATT side receivable counter in step S10, and the process proceeds to step S11. If NO, the process skips step S10 and proceeds to step S11. In step S11, it is determined whether or not the search is completed (all channels have been searched). If NO, the process returns to step S2. If YES, the process proceeds to step S12, and the count number of the ATT-side receivable counter is set. Compare the number of Amp-side receivable counters. Here, if the number of ATT counters == the number of Amp counters (Yes), the process proceeds to step S13, and the C / N values of the Amp side and the ATT side are compared for each receivable channel from the stored reception state information. The “C / N dominance counter” that counts the number of channels on which the C / N dominates on both the ATT side and the ATT side is counted up. In step S14, the C / N superior counter value is compared, and if the number of ATT side C / N superior counters is greater than the number of Amp side C / N superior counters (Yes), the process proceeds to step S15 and switches 9a and 9b to the ATT side. Is fixed and the process is terminated. On the other hand, if the number of ATT side C / N dominance counters is not greater than the number of Amp side C / N dominance counters (No), the process proceeds to step S16, the switches 9a and 9b are fixed to the Amp side, and the process ends. In the case of the same number, it is fixed to the Amp side.

  In step S12, if the number of receivable counters is not the same on the Amp side and the ATT side (No), the process proceeds to step S17, and if the number of ATT counters is greater than the number of Amp counters (Yes), the process proceeds to step S18 and proceeds to the ATT side. The switches 9a and 9b are fixed to, and the processing is terminated. If the number of ATT counters is not greater than the number of Amp counters (No), the process proceeds to step S19, the switches 9a and 9b are fixed on the Amp side, and the process is terminated.

  By the above processing, the reception state when switching to ATT and Amp is obtained for each channel, and when the number of receivable channels is the same for ATT and Amp, the channel with higher C / N By fixing to a larger number, it is possible to set to a better reception state.

(2) FIG. 3 is a flowchart showing a flow of processing based on an algorithm different from that in FIG. 2, that is, a second method for searching while acquiring information of Amp and ATT for each channel. First, the search is started in step S21, and the switch is set to the Amp side in step S22. Next, in step S23, a frequency is set (tuned) to the tuner. In step S24, the demodulation circuit 19 in FIG. 1 determines whether or not synchronization is established. If synchronization is not established (No), the process proceeds to step S29. If synchronization is established (Yes), the process proceeds to step S25, where the reception state information is acquired and stored in the storage means 33. In step S26, whether or not normal reception is possible is determined based on the values of CN and BER. If it is determined that the signal can be normally received (Yes), the process proceeds to step S27, and “1” is added to the Amp-side counter. In No, it progresses to Step S28 and detects AGC outputted from demodulation circuit 19. Since the AGC keeps the input signal level constant, information on the AGC control amount, that is, the amplification factor can be acquired. For example, if the AGC control amount operates in the range of 0 to 255 and the gain increases as the numerical value increases, that is, the input signal power is weak, if the AGC exceeds 35, the power is not strong (No) Proceed to step S33. For example, if AGC is 35 or less (Yes), it is determined as a strong electric field, set to the ATT side in step S29, reception state information is acquired in step S30 and stored in the storage means 33, and normal reception is possible in step S31. Is determined based on CN and BER. If it is determined that normal reception is possible (Yes), the process proceeds to step S32, and "1" is added to the ATT side. If it is determined that normal reception is not possible (No), the process proceeds to step S33.

In step S33, it is determined whether or not the search has been completed for all channels. If No, the process is continued from step S22 for the next channel. If it is determined in step S33 that the search is complete (Yes), the process proceeds to step S34, where the number of ATT-side receivable counters is compared with the number of Amp-side receivable counters. If the number is the same (Yes), the process proceeds to step S35, and the C / N values of the Amp side and the ATT side are compared for each receivable channel from the stored reception state information. Count up the “C / N advantage counter” that counts the number of channels where N is dominant. In step S36, the C / N superior counter value is compared. If the number of ATT side C / N superior counters is greater than the number of Amp side C / N superior counters (Yes), the process proceeds to step S37 and the switch 9a.
9b is fixed and the process is terminated. On the other hand, if the number of ATT side C / N dominance counters is not greater than the number of Amp side C / N dominance counters (No), the process proceeds to step S38, the switches 9a and 9b are fixed to the Amp side, and the process ends. In the case of the same number, it is fixed to the Amp side. In step S34, if the number of receivable counters is not the same on the Amp side and the ATT side (No), the process proceeds to step S39, and if the number of ATT counters is greater than the number of Amp counters (Yes), the process proceeds to step S40 and proceeds to the ATT side. The switches 9a and 9b are fixed to, and the processing is terminated. If the number of ATT counters is not greater than the number of Amp counters (No), the process proceeds to step S41, the switches 9a and 9b are fixed on the Amp side, and the process ends.

  As described above, in the process shown in FIG. 3, only when the amplifier side determines that “normal reception is not possible” and it is determined that “not strong power” from the AGC value, it does not switch to the attenuator side. To go to the next channel. This is because if reception is deteriorated and the power is not high, there is no possibility of reception even when switching to the attenuator side.

(3) FIG. 4 shows an example of a method for performing a search again on the ATT side when at least one or more “signals with strong power but cannot be received normally” are detected after an all-channel search on the Amp side. It is a flowchart figure. When the search is started, a switch is set on the Amp side in step S42. In step S43, the re-search flag is used, and the re-search flag is initialized and set to FALSE. Next, frequency setting (tune selection) is performed in the tuner in step S44, and in step S45, it is determined whether or not synchronization has been achieved. In the case of Yes, it progresses to step S46, acquires reception information, determines whether it can be received normally in step S47, and in the case of Yes, adds "1" to the Amp side counter in step S48, Proceed to step S49. In No, it progresses to step S50, AGC output from the demodulation circuit 19 is detected, for example, if AGC exceeds 35, it will not be strong power (No) and will progress to step S49. For example, if AGC is 35 or less (Yes), it is determined that this signal is strong power and the reception state is deteriorated, the re-search flag is set to TRUE in step S51, and the process proceeds to step S49.

  In step S49, it is determined whether or not the search has been completed for all the channels. If No, the process returns to step S44 and the same processing is performed for the other channels. In the case of Yes, it progresses to step S52 and it is determined whether a re-search flag is TRUE. In the case of No, since it is determined that there is no channel in the reception environment for the signal “high power and reception state has deteriorated”, the switch is fixed to the Amp side in step S53. The process ends (step S54). In the case of Yes, it progresses to step S55, a switch is set to the ATT side, a channel selection is performed in step S56, and it is determined whether the synchronization was taken in step S57. When synchronization is established (Yes), the process proceeds to step S58, where reception status information is acquired and stored in the storage means 33. If synchronization cannot be established (No), the process proceeds to step S61. After acquiring the reception state information in step S58, it is determined in step S59 whether or not reception is possible normally. In No, it progresses to Step S61. In the case of Yes, it progresses to step S60, "1" is added to an ATT side counter, and it progresses to step S61.

  In step S61, it is determined whether or not all channel searches on the ATT side have been completed. If no, the process returns to step S56 and the same processing is performed for the other channels. In the case of Yes, it progresses to step S62 and compares an ATT side receivable counter with an Amp side receivable counter. If the number of ATT counters is equal to the number of Amp counters, in step S63, the C / N values on the Amp side and ATT side are compared for each receivable channel from the stored reception state information, and the Amp side and ATT side respectively. A “C / N superior counter” that counts the number of channels in which C / N is dominant is counted up. In step S64, the C / N superior counter value is compared and fixed to the larger counter value. In the case of the same number, it is fixed to the Amp side.

  As shown in FIG. 4, one “re-search flag” is provided in the apparatus, channel search is first performed on the amplifier side, and reception status information (AGC, BER, C / N) is obtained for each channel. If reception is possible, the amplifier side counter is counted up. At this time, if it is determined that “normal reception is not possible” and if it is determined that “it is high power” from the value of AGC, a “research flag” is set. If the “re-search flag” is set after the search is completed, the same processing is performed by switching to the amplifier side. In other words, after channel search on the amplifier side, the search is switched to the attenuator side only when there is a channel that "cannot receive normally" and "high power" even with one channel, so the processing amount is small. There is an advantage that the number of cases increases. After that, the number of channels that can be received on the amplifier side and the attenuator side is compared, and if the number is the same, it is possible to set to a better reception state by performing comparison by C / N. .

  FIG. 1B is a diagram illustrating a configuration example of a double (plurality) tuner type broadcast receiving apparatus. Unlike FIG. 1A, in the configuration shown in FIG. 1B, in addition to the tuner unit 8, a second tuner unit 8a is provided. In the above, referring to FIG. 1A, after the initial search, it was determined whether either the amplifier or the attenuator is in an appropriate environment and fixed to one, but this method actually uses two tuners. The double tuner configuration provided is more suitable when an amplifier and an attenuator are provided in the splitter section (within the splitter housing).

In FIG. 1B, in the case of a double tuner configuration including two tuners, an amplifier Amp and an attenuator ATT are provided in the splitter section (in the splitter housing), and a splitter 6a is provided downstream of ATT5 and Amp7. Signals are input to the tuners 8 and 8a, respectively. In this case, since the setting of the amplifier Amp / attenuator ATT affects both tuners, it is better to fix to either one than to switch the amplifier Amp / attenuator ATT for each reception channel.

For example, when 13ch cannot be normally received unless it is on the amplifier Amp side, and 14ch is in an environment where it cannot be normally received unless it is on the attenuator ATT side, tuner 8 (for normal viewing) receives 13ch and tuner 8a (for recording output) ) Has a problem that, when 14ch is received, if it is switched to the amplifier Amp side in accordance with the tuning of the tuner 8, the 14ch of the tuner 8a cannot be received and normal recording cannot be performed. Therefore, as shown in the above (1) to (3), it is preferable to fix the amplifier / attenuator to the preferred one in each reception environment.

  FIG. 5 is a diagram illustrating a power range in which reception is possible in the reception apparatus according to the present embodiment. The horizontal axis is the received power (dBm). If the average reception level is R1 (for example, −60 to −30 dBm), for example, R2 (−80 to 0 dBm) is used in the conventional technique. In contrast, according to the present embodiment, in addition to the range of R2, the power range of R6 can be received when ATT is set, and the power range of R5 can be received when Amp is set. As shown in R3 and R4, −90 to +10 dBm It can cover a wide range to the extent.

  As explained above, for example, it is possible to receive a broadcast well even in an area where a high power signal is received near the transmission tower or in an environment where the signal is excessively amplified by a booster. Even in places where only reception is possible, broadcasts can be received well.

  The present invention can be used for a digital broadcast receiving apparatus.

DESCRIPTION OF SYMBOLS 1 ... Antenna, 5 ... ATT, 7 ... Amp, 8 ... Tuner, 9 ... Switch, 31 ... Reception status information detection means, 32 ... Control means, 33 ... Storage means.

Claims (5)

A television receiver having a signal power increase / decrease unit for amplifying and attenuating signal power input to a tuner between an antenna and a tuner,
The signal power increase / decrease unit has a switch unit that switches between an amplifier and an attenuator,
In the channel search, the switch is fixed to the more receivable channels on the amplification side and the attenuation side,
When the number of receivable channels is the same on the amplifying side and the attenuating side, the switch is fixed to the side where there are more receivable channels where the reception state is dominant. A television receiver having a signal power increase / decrease unit for amplifying and attenuating signal power input to a tuner between an antenna and a tuner,
A reception state detector that detects AGC, C / N, and BER based on an output signal from the tuner;
Based on the detection result of the reception state detection unit, it is determined whether or not the signal of the channel can be normally received, and according to the determination result, feedback of amplification or attenuation of the signal power in the signal power increase / decrease unit A control unit for controlling,
The signal power increase / decrease unit has a switch unit that switches between an amplifier and an attenuator,
In the channel search, from the reception state information detected by the reception state detection unit, a receivable counter unit for counting the number of channels that can be received on each of the attenuation side and the amplification side, and among the receivable channels A C / N dominance counter for counting the number of channels where C / N dominates on each of the attenuation side and the amplification side;
Based on the reception status information, it is determined whether each channel is normally receivable. When it is determined that each channel is normally receivable, either the attenuation side or the amplification side is applicable. Count up the receivable counter
At the end of the channel search, each receivable counter value is compared, and the switch is fixed so that more channels can be normally received. If the receivable counter values are the same, the storage means When it is determined from the reception state information stored in the above whether each of the receivable channels has a higher C / N between the attenuation side and the amplification side, and when it is determined that the C / N is higher on the attenuation side. Counts up the C / N dominance counter on the attenuating side. If it is determined that the C / N is higher on the amplifying side, the C / N dominating counter on the amplifying side is counted up. A television receiver characterized by comparing the values and fixing the switch so that the C / N becomes higher in more channels.   In the channel search, when the switch unit is received on the amplification side, it is determined as “not normally received” based on the detection result of the reception state detection unit, and “is not strong power” from the value of the AGC. 3. The television receiver according to claim 2, wherein only when it is determined, the process proceeds to the next channel without switching to the attenuation side.   The television receiving apparatus has a configuration including at least two tuners of first and second, and has a configuration in which an amplifier and an attenuator are provided in a splitter unit that distributes a signal to the tuner. The television receiver according to claim 2 or 3, Perform channel search on the amplification side, acquire the reception status information in each channel and store it in the storage means. If normal reception is possible, the amplifier side receivable counter is counted up, and “normal reception is not possible” And a flag storage unit that stores a re-search flag that is set to “1” when at least one channel of a signal that is determined to be stronger than the value of AGC is generated,
After the channel search on the amplification side is completed, if the re-search flag in the flag storage unit is “1”, the channel search is switched to the attenuation side and the same channel search is performed. Compare the values and fix the switch to the direction where more channels can be received normally,
When the receivable counter values are the same number, it is determined from the reception state information stored in the storage means which of the attenuation side and the amplification side has a higher C / N in each receivable channel, When it is determined that the C / N is higher on the attenuation side, the C / N superior counter on the attenuation side is counted up, and when it is determined that the C / N is higher on the amplification side, the C / N on the amplification side is counted. 5. The television receiver according to claim 2, wherein an N-dominance counter is counted up and the switch is fixed in such a manner that C / N becomes higher in more channels.

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