JP2006229590A - Ground digital broadcast retransmitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ground digital broadcast retransmitting device which is configured at a low cost, capable of surely receiving channels remaining at a low receiving level, and adjusting the received broadcasting signals to a prescribed signal level so as to retransmit. <P>SOLUTION: Signals of a to e channels received through an antenna 10 are distributed by a distributer 13 to a wide band amplifying device 14 and a single channel amplifying device 20. The wide band amplifying device 14 amplifies the signals of a to e channels through a wide band amplifier 15. The single channel amplifying device 20 selects the signals of the e channel out of input signals through a band-path filter 21, amplifies the selected signals of the e channel through an amplifier 22, inputs the amplified signals of the e channel into a mixer 23, mixes the amplified signals of the e channel with local oscillation signals so as to convert the amplified signals of the e channel into the signals of an e' channel having no effect on the other broadcasting signals etc, furthermore amplifies the signals of the e' channel through an amplifier 25, and outputs the amplified signals of the e' channel through the intermediary of a band-pass filter 26. A mixer 16 mixes the signals of a to e channels amplified through the wide band amplifying device 14 and the signals of the e' channel outputted from the singe channel amplifying device 20 together, and the mixed signals are outputted from the output terminal 17 to a transmission path. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a terrestrial digital broadcast re-transmission apparatus that receives terrestrial digital television broadcasts, performs processing such as amplification and frequency conversion, and retransmits them to a joint reception facility by a joint reception system.

  Terrestrial digital television broadcasting uses the UHF band to transmit in the OFDM (Orthogonal Frequency Division Multiplex) method, and most of the 6 MHz frequency band assigned to each channel. (5.6 MHz) is used.

  Conventional analog television broadcasting basically does not use adjacent channels, but terrestrial digital television broadcasting arranges signals in adjacent channels. When the transmission wave of each channel is transmitted from the same antenna with the same output, there is no significant difference in the level of the adjacent channel at the receiving point, but when it is transmitted with a different antenna or different output, there is a large difference in the adjacent level. There are things to do.

  That is, in terrestrial digital television broadcasting, there are wide-area broadcasts that are transmitted from a common antenna to a wide-area area, and prefectural-area broadcasts that are broadcast independently for each prefecture. The channel arrangement in each broadcasting area is almost constant. For example, about 7 channels of broadcast waves are transmitted from a shared antenna tower in wide area broadcasting, and one broadcast wave is transmitted from the antenna of each broadcasting station in prefecture broadcasting. . In this case, in the prefectural broadcasting, usually, for example, about 1 to 3 broadcasting stations are provided. Since wide-area broadcast channels are transmitted from the same antenna with the same output, the reception level at the reception point is relatively constant and stable. However, since the prefectural broadcast channel is transmitted from the prefectural broadcast station antenna and its transmission output is often different from that of the wide area broadcast, the reception level between the wide area broadcast channel and the prefectural broadcast channel as shown in FIG. Large differences may occur. FIG. 9 shows the reception level situation of channels a to e, for example, at the reception point. The reception levels of channels a to d (wide area broadcast) are almost the same, and the reception level of channel e (prefectural area broadcast) is small. A state in which a level difference A is generated with respect to an adjacent d channel is shown.

As described above, in terrestrial digital television broadcasting, signals are arranged in adjacent channels, and the reception level of a specific channel at a reception point may be low.
For this reason, in a conventional terrestrial digital broadcast retransmitting apparatus that receives a digital terrestrial television broadcast, amplifies it, and retransmits the digital terrestrial television broadcast to a joint reception facility or the like by means of a joint reception system, generally one terrestrial digital television broadcast is transmitted for each channel. Each signal is received, signals outside the band are suppressed, and the received signal is adjusted to a predetermined level and then output to the transmission line (see, for example, Patent Document 1).

  A conventional terrestrial digital broadcast retransmission apparatus is configured as shown in FIG. 10, for example. That is, terrestrial digital television broadcasting in the UHF band of 470 MHz to 770 MHz is received by the antenna 1 and distributed to the plurality of retransmission amplifying units 3 a to 3 n by the distributor 2. The re-transmission amplifiers 3a to 3n use single-channel signal amplifiers called signal processors, adjust the signal level of each channel, for example, a to e channels, and output the signals with the signal levels of all channels being constant. The output signals of the retransmission amplifiers 3 a to 3 n are mixed by the mixer 4 and then transmitted from the output terminal 5 to the system subscriber's house via the transmission line 6. In this case, since the signal transmitted through the transmission line 6 is attenuated due to transmission loss or the like during the transmission, an amplification device 7 is provided in the transmission line 6 at predetermined intervals to perform signal amplification and frequency characteristic correction. ing.

On the other hand, at the system subscriber's home, the television signal sent through the transmission path 6 is received by the television receiver. In general, a television receiver for digital broadcast reception searches all channels at the time of initial setting to create a receivable channel list, and then selects a reception channel based on this channel list (for example, (See Patent Document 1). When creating the receivable channel list, whether or not a channel is received is determined based on whether or not a TS (Transport Stream) is received.
JP 2003-309739 A JP 2004-282221 A

  As described above, in terrestrial digital television broadcasting, signals are arranged in adjacent channels, and there are a group of channels called wide-area broadcasting and several channels called prefectural broadcasting in each region. Large differences in reception levels may occur. For this reason, the conventional terrestrial digital broadcast retransmission apparatus has a problem that it becomes very expensive because the retransmission amplification units 3a to 3n are provided for each channel to process signals.

  The present invention has been made in order to solve the above-described problems, and can be configured inexpensively, can reliably receive even a channel with a low reception level, can be adjusted to a predetermined signal level, and can be retransmitted. An object is to provide a retransmission apparatus.

  A terrestrial digital broadcast retransmission apparatus according to a first aspect of the present invention is a broadband amplifying apparatus that collectively amplifies a plurality of channels of digital television broadcast signals received by an antenna, and a digital television broadcast signal received by the antenna. A single-channel amplifying device that selects a signal of a specific channel with a low reception level from among them, amplifies the signal to an appropriate level, and converts the frequency to a frequency region that does not affect other broadcast signals and the like, and the broadband amplifying device. And a mixer that mixes a plurality of channels of signals amplified together and a signal of a specific channel amplified and frequency-converted by the single-channel amplifier and outputs the mixed signal to a transmission line.

A terrestrial digital broadcast retransmitting apparatus according to a second aspect of the present invention is a broadband amplifying apparatus that collectively amplifies a plurality of channels of digital television broadcast signals received by an antenna, and a digital television broadcast signal received by the antenna. A single-channel amplifying device that selects a signal of a specific channel with a low reception level from among them, amplifies it to an appropriate level and converts it to a frequency region that does not affect other broadcast signals, etc., and the broadband amplifying device collectively A mixer that mixes the amplified signal of the plurality of channels and the signal of the channel amplified and frequency-converted by the single-channel amplification device and outputs the mixed signal to the transmission line,
The broadband amplifying device includes an interference wave generator that generates an interference wave signal for a specific channel selected by the single channel amplifier, and the interference wave signal generated by the interference wave generator is mixed in the amplified signal, The reception channel is configured to cause a reception failure with respect to the specific channel.

  According to the present invention, in a digital television broadcast reception area where there are a group of channels with little difference in reception level and a specific channel with a low reception level, a plurality of channels received by an antenna are collectively processed by a wideband amplifier. For specific channels with low reception level, the structure is simplified by amplifying to a proper level with a single channel amplification device and re-transmission after frequency conversion to a frequency region that does not affect other broadcast signals etc. The cost can be reduced, and a specific channel with a low reception level can be reliably received by the television receiver connected to the transmission path.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing the configuration of the terrestrial digital broadcast retransmission apparatus according to the first embodiment of the present invention. In FIG. 1, reference numeral 10 denotes a UHF receiving antenna, which receives, for example, terrestrial digital television broadcasting in the UHF band of 470 MHz to 770 MHz. A signal received by the antenna 10 is input to the input terminal 12 of the terrestrial digital broadcast retransmission apparatus 11. The signal input to the input terminal 12 is divided into two by the distributor 13, one of the distribution signals is input to the wideband amplifier 14, and the other distribution signal is input to the single channel amplifier 20.

  The broadband amplifying device 14 is configured by using a broadband amplifier 15 and amplifies all channel signals received by the UHF receiving antenna 10 collectively. The signal amplified by the broadband amplifier 15 is input to the mixer 16.

  On the other hand, the single channel amplifying apparatus 20 includes, for example, a band pass filter (BPF) 21, a single channel amplifier 22, a mixer 23, a local oscillator 24, a single channel amplifier 25, and a band pass filter (BPF) 26. A specific channel with a low level is selected, amplified to an appropriate level, converted to a frequency region that does not affect other broadcast signals, etc., and output.

  The bandpass filter 21 is for selecting a specific channel with a low reception level, but does not necessarily have a steep characteristic, and may be any filter that can appropriately suppress the signal level of other channels. Since a channel with a low reception level is specified by each reception area where the television broadcast is received, the frequency of the bandpass filter 21 is set in advance according to the channel.

  The signal selected by the bandpass filter 21 is amplified by an amplifier 22 and then input to a mixer 23 constituting a frequency conversion circuit. A local oscillation signal is input from the local oscillator 24 to the mixer 23. The mixer 23 converts the specific channel amplified by the amplifier 22 into an empty channel, that is, a frequency region that does not affect other broadcast signals and the like, and adjusts the oscillation frequency Lo of the local oscillator 24 to the empty channel. Set.

  The signal frequency-converted by the mixer 23 is input to the amplifier 25 to be amplified and output through the band pass filter 26. The output signal of the band pass filter 26 is input to the mixer 16 as the output of the single channel amplifier 20. The bandpass filter 26 is set with a passband frequency so as to select a channel frequency-converted by the mixer 23.

  The mixer 16 mixes a plurality of channel signals amplified by the wideband amplifier 14 and a specific channel signal amplified and frequency-converted by the single channel amplifier 20, and outputs the signal from the output terminal 17 to the common reception system. Output to a transmission line (not shown).

Next, the operation of the terrestrial digital broadcast re-transmission apparatus 11 configured as described above is received and retransmitted, for example, as shown in FIG. 2, in the UHF band a to e channels (ch). The case will be described. In this case, it is assumed that the reception levels of the channels a to d are substantially the same and the reception level of the e channel is low. As a specific example,
a = 19 channels (center frequency: 509 MHz)
b = 20 channels (center frequency: 515 MHz)
c = 21 channels (center frequency: 521 MHz)
d = 22 channels (center frequency: 527 MHz)
e = 23 channels (center frequency: 533 MHz)
Signal is received.

  Further, when the specific channel having a low reception level is 23 channels (center frequency: 533 MHz), the band is 530 to 536 MHz, so the pass band of the band pass filter 21 is set to 530 to 536 MHz. Further, the e channel is converted to a signal e 'of 32 channels (584 to 590 MHz), for example, and the oscillation frequency Lo of the local oscillator 24 is set to 54 MHz. Therefore, as the band pass filter 26, a pass band is set so as to select a signal of 584 to 590 MHz that is 32 channels.

  In the above-described configuration, broadcast signals of channels a to e are received by the UHF receiving antenna 10 and input to the distributor 13 from the input terminal 12. The distributor 13 distributes the broadcast signals of the a to e channels received by the UHF receiving antenna 10 and inputs them to the wideband amplifier 14 and the single channel amplifier 20. The a to e channel signals input to the broadband amplifier 14 are amplified by the broadband amplifier 15 and input to the mixer 16.

  Further, the signal input to the single channel amplifier 20 is selected from the e-channel signal by the bandpass filter 21, amplified by the amplifier 22, input to the mixer 23, and mixed with the local oscillation signal to generate 32 channels. (584-590 MHz) signal, that is, an e ′ channel signal. The signal of the e ′ channel is amplified to an appropriate level by the amplifier 25, selected by the band pass filter 26, and sent to the mixer 16.

  As shown in FIG. 2, the mixer 16 mixes the a to e channels amplified by the broadband amplifying device 14 and the e ′ channel output from the single channel amplifying device 20, and transmits from the output terminal 17 to the joint reception system. Output to the path, ie retransmit. At this time, if the characteristics of the bandpass filter 21 are not steep and have moderate characteristics to some extent, the bandpass filter 21 outputs the c and d channel signals in a suppressed state, and the mixer 23 outputs c ′ (30 Channel) and d ′ (31 channel) signals, and input to the mixer 16 via the amplifier 25 and the band-pass filter 26. Therefore, the signals mixed by the mixer 16 include the suppressed c 'and d' channel signals as well as the a to e channel signals and the e 'channel signal, as shown in FIG.

  As described above, the a to e channel signals received by the UHF receiving antenna 10 are amplified by the broadband amplifying device 14, and the e channel signals having a low reception level are amplified and frequency-converted by the single channel amplifying device 20. The The a to e channel signals amplified by the broadband amplifying device 14 and the c ′, d ′, and e ′ channel signals output from the single channel amplifying device 20 are mixed by the mixer 16 and transmitted from the output terminal 17 to the transmission line. Is output.

  Of the signals output from the terrestrial digital broadcast re-transmission device 11 to the transmission line of the joint reception system, the signals of the channels a to d do not have much difference in level, and therefore the signals are arranged in adjacent channels. Can be received by the television receiver without any problem. Further, since the e-channel signal amplified by the single-channel amplifier 20 is frequency-converted to a frequency region that does not affect other broadcast signals or the like, it can be reliably received by the television receiver. In this case, there are a plurality of signals (e, e ′) having the same network ID, but the television receiver searches all channels at the time of initial setting, selects a channel with a good reception state, and displays a list. Therefore, the e ′ channel having the good reception state among the e and e ′ channels is registered in the channel list.

  That is, when the signals of the e channel and the e ′ channel are compared, the e channel signal has a considerably lower level than the adjacent channel, whereas the e ′ channel signal has an appropriate level and the adjacent channel d ′ signal. Therefore, the television receiver selects the e ′ channel and registers it in the list when searching all channels. Therefore, even when there are a plurality of signals (e, e ') having the same network ID, the television receiver can correctly select and receive the e' channel signal. In addition, there are a plurality of signals (c, c ′ and d, d ′) having the same network ID as the signals of the c and d channels. In this case, the signal levels of the c ′ and d ′ channels are c. Since it is considerably lower than the signals of the d and d channels, the c and d channels are correctly selected and received.

  According to the first embodiment, a single channel amplification is applied to a channel having a low reception level in a region where a channel such as a prefectural broadcast having a low reception level exists, compared to a group of channels such as a wide-area broadcast having little difference in reception level. Since the apparatus 20 amplifies the signal to an appropriate level and converts the frequency to a frequency region that does not affect other broadcast signals and the like, and outputs it to the transmission line of the joint reception system, the system subscriber even if the channel has a low reception level. It can be reliably received by a television receiver at home. In addition, a wide-band amplifier 15 can amplify a wide-band broadcasting channel group with little difference in reception level, so that the configuration of the digital terrestrial broadcasting retransmission apparatus 11 can be simplified and the cost can be reduced. Can be achieved.

(Second Embodiment)
Next, a digital terrestrial broadcast retransmission apparatus according to a second embodiment of the present invention will be described.
In the first embodiment, the case where the single channel amplifying apparatus 20 that selects and amplifies the e channel from the signal distributed by the distributor 13 directly converts the frequency of the e channel into the e ′ channel has been described. In the second embodiment, as shown in FIG. 3, a single channel amplifying device 20 is provided in place of the single channel amplifying device 20, and the e channel is selected from the signals distributed by the distributor 13 and is temporarily converted into an intermediate frequency signal IF. Thereafter, the intermediate frequency signal IF is frequency-converted to the e ′ channel. Since other configurations are the same as those of the first embodiment, the same portions are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 3, the single channel amplifying apparatus 20 includes a first frequency conversion unit 30a that converts an e channel into an intermediate frequency signal IF, and other intermediate frequency signals converted by the first frequency conversion unit 30a. The second frequency conversion unit 30b performs frequency conversion to the e ′ channel, which is a frequency region that does not affect the broadcast signal or the like.

  The first frequency converter 30a includes a bandpass filter 21 for selecting an e channel, an amplifier 22 for amplifying an e channel signal, a mixer 23 for converting a signal amplified by the amplifier 22 into an intermediate frequency signal IF, and a local unit. An oscillator 24, an amplifier 25 for amplifying the intermediate frequency signal IF converted by the mixer 23, and a band-pass filter 26 for selecting the intermediate frequency signal IF amplified by the amplifier 25. The e channel signal is an intermediate frequency signal IF. The oscillation frequency of the local oscillator 24 is set so as to be converted to. For example, when the e channel is 23 channels (center frequency 533 MHz) and the intermediate frequency signal IF is 57 MHz, the oscillation frequency Lo1 of the local oscillator 24 is a value obtained by adding the center frequency 533 MHz of the e channel and 57 MHz of the intermediate frequency signal IF, That is, “Lo1 = 533 + 57 MHz = 590 MHz” is set. The bandpass filter 21 sets the center frequency of the passband to 533 MHz (band 6 MHz), and the bandpass filter 26 sets the center frequency of the passband to 57 MHz (band 6 MHz).

  The second frequency converter 30b includes an amplifier 31 that amplifies the intermediate frequency signal IF, a mixer 32 that converts the intermediate frequency signal IF into an e ′ channel signal, a local oscillator 33, and an amplifier that amplifies the e ′ channel signal. 34, comprising a band-pass filter 26 for selecting the signal of the e ′ channel, and the oscillation frequency of the local oscillator 33 is set so that the intermediate frequency signal IF is converted into the e ′ channel. For example, when the intermediate frequency signal IF is 57 MHz and the e ′ channel is 32 channels (center frequency 587 MHz), the oscillation frequency Lo2 of the local oscillator 33 is a value obtained by adding the center frequency 587 MHz of the e ′ channel and 57 MHz of the intermediate frequency signal IF. That is, “Lo2 = 587 + 57 MHz = 644 MHz” is set. The band pass filter 35 sets the center frequency of the pass band to 587 MHz (band 6 MHz).

  As described above, in the single channel amplifying apparatus 20, the e channel is selected from the signals distributed by the distributor 13 and converted into the intermediate frequency signal IF, and then the intermediate frequency signal IF is converted into the e ′ channel. By conversion, only the signal of the e ′ channel can be selected and output as shown in FIG. The e ′ channel signal is input to the mixer 16, mixed with the signals a to e amplified by the wideband amplifier 14, and output from the output terminal 17 to the transmission line of the common reception system.

  According to the second embodiment, in the single channel amplifying apparatus 20, only the target e channel can be selected and frequency-converted to the e ′ channel, and the signal of the channel adjacent to the e channel can be removed. The television receiver provided in the system subscriber's home can reliably receive the broadcasts of the channels a to d and the e ′ channel (e channel).

(Third embodiment)
Next, a digital terrestrial broadcast retransmission apparatus according to a third embodiment of the present invention will be described.
In digital terrestrial television broadcasting, radio waves are transmitted using the UHF band as described above. For this reason, in the case of a joint reception facility that does not have the UHF band or already uses the same band as the broadcast, the received digital terrestrial television broadcast signal is converted into another frequency band and used as a transmission line for the joint reception system. Need to retransmit.

  In the third embodiment, an example in which the received digital terrestrial television broadcast signal is converted into another frequency band and transmitted to the transmission path of the joint reception system is shown. Note that the reception conditions of the television broadcast at the reception point are the same as those in the above embodiment, and when the a to e channel television broadcast is received as shown in FIG. It shall be low.

  FIG. 5 shows a configuration example of the terrestrial digital broadcast retransmission apparatus 11 according to the third embodiment, and the wideband amplification apparatus 14 is configured as follows. That is, the wideband amplifying apparatus 14 converts the bandpass filter 41, the wideband amplifier 15, and the ad channels to select the signals of the ad channels to the a ′ to d ′ channels in the frequency band that does not affect other broadcast signals and the like. A mixer 42 and a local oscillator 43 for converting, a wideband amplifier 44 for amplifying the frequency-converted signals of the a ′ to d ′ channels, and a bandpass filter 45 for selecting the a ′ to d ′ channels. The single-channel amplifier 20 has the same configuration as that shown in the second embodiment, but the IF signal converted by the first frequency converter 30a is converted to the e ′ channel by the second frequency converter 30b. Is converted to a different e "channel.

Next, a specific setting example of each unit will be described. The bandpass filter 41 of the wideband amplifier 14 is set to a signal band of ad channels, that is, a pass band of 506 to 530 MHz. The channels a to d are channels a ′ to d ′ in a frequency band between the third channel and the fourth channel of analog television broadcasting (VHF band), for example, as shown in FIG.
a ′ = C15 channel (center frequency: 123 MHz)
b '= C16 channel (center frequency: 129 MHz)
c ′ = C17 channel (center frequency: 135 MHz)
d '= C18 channel (center frequency: 141 MHz)
Convert to At this time, since the center frequency of the channels a to e is 521 MHz and the center frequency of the channels a ′ to e ′ is 135 MHz, the local transmission frequency Lo3 of the local oscillator 43 is set to “Lo3 = 521-135 = 386 MHz”. The band pass filter 45 is set so as to select the signal band of the a ′ to d ′ channel, that is, the pass band of 120 to 144 MHz.

  Further, the single channel amplifier 20 sets the transmission frequency Lo1 of the local oscillator 24 to “Lo1 = 533 + 57 MHz = 590 MHz” when the intermediate frequency IF converted by the first frequency converter 30a is 57 MHz. If the 57 MHz intermediate frequency signal IF converted by the first frequency converter 30a is converted to the e "channel, that is, the C22 channel (center frequency: 167 MHz) by the second frequency converter 30b, the second The oscillation frequency Lo2 of the local oscillator 33 in the frequency converter 30b is set to “Lo2 = 167 + 57 MHz = 224 MHz”. The bandpass filter 35 sets the center frequency of the pass band to 167 MHz (band 6 MHz).

  With the above setting, the broadband amplifying apparatus 14 selects the a to d channel signals among the a to e channels distributed by the distributor 13 by the band pass filter 41 and amplifies the signals by the broadband amplifier 15. The frequency is converted into channels a ′ to d ′ by the mixer 42, further amplified by the broadband amplifier 44, and output through the band pass filter 45. In this case, the band-pass filters 41 and 45 are not steep in filter characteristics and have a certain pass band with respect to the adjacent channels. Therefore, as shown in FIG. The e channel is also frequency-converted to the e ′ channel and output.

  On the other hand, the single channel amplifying apparatus 20 converts the e channel signal from the a to e channels distributed by the distributor 13 into the intermediate frequency signal IF by the first frequency converter 30a, and converts the intermediate frequency signal IF to the intermediate frequency signal IF. The second frequency conversion unit 30b converts the signal into e "channel and outputs it.

  The a ′ to e ′ channel signal output from the broadband amplifier 14 and the e ″ channel signal output from the single channel amplifier 20 are mixed by the mixer 16 and output from the output terminal 17.

  As described above, in the third embodiment, even in the case of a joint reception facility that does not have a UHF band or already uses the same band as a broadcast, the received terrestrial digital television broadcast signal is converted into another broadcast signal or the like. The frequency can be converted to a frequency region that does not affect the output. In this case, there are a plurality of signals (e ′, e ″) having the same network ID on the transmission path of the joint reception system. There is no problem because it is recognized as a channel. In this example, since the signal level of the e ″ channel is larger and stable than the e ′ channel, the signal of the e ″ channel is selected and received. Further, in the single channel amplifying apparatus 20, only the target e channel is selected and frequency-converted to the e "channel. Therefore, in the television receiver provided in the system subscriber's house, the channels a 'to d' and It is possible to reliably receive the e "channel broadcast.

  In the third embodiment, the case where the single channel amplifying device 20 converts the e channel into the e ″ channel different from the e ′ channel has been described. However, the broadband amplifying device 14 collectively converts the channels a to d. If the e ′ channel is suppressed to a level lower than a certain condition at the time of frequency conversion, the e ″ channel can be arranged at the position of the e ′ channel.

  In the third embodiment, the case where the received signal is converted to the frequency band between the third channel and the fourth channel of the analog television broadcast (VHF band) has been described. Of course, if it is not in the frequency range, it may be converted to another frequency band.

(Fourth embodiment)
Next, a digital terrestrial broadcast retransmission apparatus according to a fourth embodiment of the present invention will be described.
In the first to third embodiments, there are a plurality of signals having the same network ID, such as e, e ′ channel or e ′, e ″ channel, on the transmission path of the joint reception system. Since the signal with the better condition is recognized and received, there is no particular problem as long as the reception condition does not change much.

  However, if there are multiple signals with the same network ID at the time of initial setting, the television receiver selects the channel with the better condition and registers it in the channel list, and then receives it based on this channel list. Since the control is performed, there is a possibility that the e-channel may be registered in the channel list if the reception level of the e-channel happens to be high at the time of initial setting in an area where the reception conditions vary greatly. When the television receiver registers the e channel in the channel list, the channel selection is performed on the basis of the channel list. Therefore, even if an e ′ channel signal having a good reception condition is sent, the reception condition is poor. The e channel will be selected. The channel list can be re-registered, but the re-registration operation is very troublesome.

  For this reason, in the fourth embodiment, a channel with poor reception conditions is normally configured not to be registered in the channel list even if the reception level temporarily increases at the time of initial setting. The reception conditions of the television broadcast at the reception point are the same as those in the above embodiments, and when the a to e channel television broadcast is received as shown in FIG. 8, the reception level of the e channel is low. And

  FIG. 7 is a diagram illustrating a configuration example of the digital terrestrial broadcast retransmission apparatus 11 according to the fourth embodiment of the present invention. The fourth embodiment is different from the first embodiment shown in FIG. 1 in that a mixer 51 is provided on the output side of the wideband amplifier 15 in the wideband amplifier 14, and an interference wave generator 52 is connected to the mixer 51. Is. The interference wave generator 52 generates an interference wave signal for a channel targeted by the single channel amplifier 20, in this example, the e channel. The interference wave generated by the interference wave generator 52 has a level that causes a reception failure for the e channel even when the reception condition of the e channel is improved, such as a single carrier signal set to the frequency of the e channel. Any signal may be used as long as it is a signal. Since other configurations are the same as those in the first embodiment, the same portions are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the above configuration, the a to e channel signals received by the antenna are input to the distributor 13 from the input terminal 12, divided into two here, and input to the wideband amplifier 14 and the single channel amplifier 20. The a to e channel signals input to the broadband amplifying device 14 are amplified by the broadband amplifier 15 and input to the mixer 51, where the interference wave signal output from the interference wave generator 52 corresponds to the e channel. It is mixed. That is, as shown in FIG. 8, the interference wave signal E generated by the interference wave generator 52 is mixed in the band of the e channel.

  On the other hand, as described in the first embodiment, the single channel amplifying apparatus 20 selects and amplifies the e channel signal from the a to e channel signals distributed by the distributor 13, and the mixer 23 selects e. 'Convert frequency to channel and output. Note that, as described above, the c-channel and d-channel signals are also converted into the c ′ and d ′ channels and output from the single channel amplifier 20.

  The a to e channel signals (including the e channel jamming signal E) amplified by the broadband amplifying device 14 and the e ′ channels (including c ′ and d ′ channels) amplified by the single channel amplifying device 20 The signals are mixed by the mixer 16 and output from the output terminal 17 to the transmission line of the joint reception system.

  As described above, when the interference signal E is mixed into the e-channel having a low reception level in the broadband amplifying apparatus 14, the television receiver connected to the transmission path has good e-channel reception conditions. Even if the initial setting is performed, the e channel in which the reception failure has occurred is not selected, and the e ′ channel having no reception failure is selected and registered in the channel list. Thereafter, a channel is selected based on this channel list. As a result, even if the reception condition of the e channel is good at the time of initial setting of the television receiver, registration to the e channel list can be surely prevented.

  In each of the above embodiments, a case where the reception level of the e channel is low in the case of receiving the television broadcast of the a to e channels has been described. It is possible.

  Further, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage.

It is a block diagram which shows the structure of the terrestrial digital broadcast re-transmission apparatus which concerns on 1st Embodiment of this invention. In the embodiment, it is a figure which shows the reception level of the input signal with respect to a television receiver. It is a block diagram which shows the structure of the terrestrial digital broadcast re-transmission apparatus which concerns on 2nd Embodiment of this invention. In the embodiment, it is a figure which shows the reception level of the input signal with respect to a television receiver. It is a block diagram which shows the structure of the terrestrial digital broadcast re-transmission apparatus which concerns on 3rd Embodiment of this invention. (A) is a figure which shows the reception level condition in a receiving point, (b) is a figure which shows the reception level of the input signal with respect to a television receiver. It is a block diagram which shows the structure of the terrestrial digital broadcast re-transmission apparatus which concerns on 4th Embodiment of this invention. In the embodiment, it is a figure which shows the reception level of the input signal with respect to a television receiver. It is a figure which shows the receiving level condition in the receiving point of terrestrial digital television broadcasting. It is a block diagram which shows the structure of the conventional terrestrial digital broadcast re-transmission apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... UHF receiving antenna, 11 ... Terrestrial digital broadcast retransmitting device, 12 ... Input terminal, 13 ... Distributor, 14 ... Broadband amplifying device, 15 ... Broadband amplifier, 16 ... Mixer, 17 ... Output terminal, 20 ... Single Channel amplifying device, 21 ... band pass filter, 22, 25 ... single channel amplifier, 23 ... mixer, 24 ... local oscillator, 26 ... band pass filter, 30a ... first frequency converter, 30b ... second frequency converter 31 ... Amplifier, 32 ... Mixer, 33 ... Local oscillator, 34 ... Amplifier, 35 ... Bandpass filter, 41,45 ... Bandpass filter, 42 ... Mixer, 43 ... Local oscillator, 44 ... Wideband amplifier, 45 ... Band Pass filter, 51... Mixer, 52.

Claims (2)

  A broadband amplifying apparatus that collectively amplifies digital television broadcast signals of a plurality of channels received by an antenna, and a signal of a specific channel having a low reception level from the digital television broadcast signals received by the antenna. A single channel amplifying device that amplifies to an appropriate level and converts the frequency to a frequency region that does not affect other broadcast signals and outputs the signal, and a multi-channel signal collectively amplified by the broadband amplifying device and the single channel A terrestrial digital broadcast retransmission apparatus comprising: a mixer that mixes a signal of a specific channel amplified and frequency-converted by an amplification apparatus and outputs the mixed signal to a transmission path. A broadband amplifying apparatus that collectively amplifies digital television broadcast signals of a plurality of channels received by an antenna, and a signal of a specific channel having a low reception level from among the digital television broadcast signals received by the antenna, A single channel amplifying device that amplifies to an appropriate level and converts the frequency into a frequency region that does not affect other broadcast signals and outputs, a multi-channel signal collectively amplified by the broadband amplifying device, and the single channel amplification A mixer that mixes the signal of the channel amplified and frequency-converted by the device and outputs it to the transmission line,
The broadband amplifying device includes an interference wave generator that generates an interference wave signal for a specific channel selected by the single channel amplifier, and the interference wave signal generated by the interference wave generator is mixed in the amplified signal, A terrestrial digital broadcast re-transmission apparatus configured to cause a reception failure with respect to the specific channel.

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