JP4127556B2 - Terrestrial digital broadcast retransmitter - Google Patents

Description

  The present invention relates to a terrestrial digital broadcast re-transmission apparatus that receives a terrestrial digital broadcast signal, adjusts the transmission level of each channel in a predetermined area, and retransmits the channel. In particular, the present invention relates to an apparatus with reduced power consumption.

  Recently, terrestrial digital broadcasting has been put into practical use. In the future, after a transition period to terrestrial digital broadcasting, analog broadcasting is scheduled to stop service. However, during the transition period, it is necessary to be able to receive both analog broadcasting and terrestrial digital broadcasting. In a television joint reception system using a local network that has multiple terminals such as apartment houses such as condominiums, collections of houses in difficult-to-view areas, shopping streets, schools, and companies, digital terrestrial digital broadcasting It is difficult to switch to a broadcast receiving apparatus, and it is necessary to propagate an analog broadcast signal and a terrestrial digital broadcast signal to the transmission path of this joint reception system.

  In this television joint reception system, a re-transmission device that adjusts the transmission signal level for each channel to a constant level or changes the transmission band is necessary to prevent signal degradation. Since the level of the signal of each channel received by the antenna of the television joint reception system is different for each channel, it is necessary to perform the retransmission process for each channel. For this reason, a wideband digital terrestrial broadcast signal received by an antenna is separated by a wideband filter, and then converted to an intermediate frequency band by a down converter so that a channel to be selected is located in the intermediate frequency band. Only the signal for one channel is extracted. Then, the signal for one channel is amplified by the AGC amplifier and the transmission level is made constant, then converted to the frequency of the transmission band of the local network by the up converter, and then transmitted to the local network. . The conventional terrestrial digital broadcast retransmitting apparatus needs to provide such a channel processor for each channel, and therefore, one terrestrial digital broadcast retransmitting apparatus is downed by the number of channels to be received and retransmitted. A channel processor having a converter and an up-converter was required. Further, a terrestrial digital broadcast retransmission apparatus described in Patent Document 1 below is known.

  On the other hand, when this terrestrial digital broadcast re-transmission device is newly installed in the television joint reception system, it is necessary to supply power, but considering that in the future the analog broadcast signal re-transmission device will be removed, Therefore, it is necessary to supply power using an existing power supply device. However, the power supply apparatus requires a sufficient amount of power to be supplied to the analog broadcast signal retransmission apparatus, and the capacity to supply power to the newly installed terrestrial digital broadcast retransmission apparatus is limited.

  Therefore, the terrestrial digital broadcast retransmitting apparatus using the channel processor for each channel to be retransmitted as described above consumes too much power and cannot be supplied with the existing power supply apparatus. For this reason, when trying to newly install a terrestrial digital broadcast re-transmission device, it is necessary to add power supply facilities even during the provisional period until the end of analog broadcasting. For this reason, there has been a demand for a terrestrial digital broadcast re-transmission device with low power consumption that can supply power without adding power supply equipment.

  Japanese Patent Application Laid-Open No. H10-228561 discloses that a wide band of RF is collectively converted to an intermediate frequency band and separated by a SAW filter. However, this system basically requires a band-pass filter and a mixer that separates each channel in the RF band for each channel, and thus requires an extra band-pass filter and mixer. In addition, by providing a re-transmission unit that can be used in common for the common channel portion of the terrestrial digital broadcasting channel plan that varies from region to region, the versatility of facility use is enhanced, and channel plans in each region can be easily accommodated. There is no suggestion about what to do.

  On the other hand, since terrestrial digital broadcasting has a different channel plan for each region, conventionally, for each channel, the high frequency band is converted to an intermediate frequency band by a down converter, and only a desired signal for one channel is extracted and then amplified. Therefore, it has been necessary to convert the data into a predetermined channel band to be retransmitted and to transmit it. That is, if all the bands are processed at once, even if the power consumption can be reduced, the signal level to be transmitted most often for each channel cannot be adjusted, so this method cannot actually be used.

Therefore, an object of the present invention is to reduce the power consumption of the terrestrial digital broadcast retransmitting device by making the transmission signal level controllable for each channel.
JP-A-2005-27241

The invention of claim 1 for solving the above-mentioned problems, which receives a terrestrial digital broadcasting signal, the terrestrial digital broadcasting retransmission apparatus for retransmitting in a predetermined area, continuous among the terrestrial digital broadcasting band 3 Ji Yaneru min Down converter that converts the band into an intermediate frequency band, a first distributor that distributes the output of the down converter to the number of each channel, and an intermediate frequency for each channel that is required for retransmission of the signal distributed by the first distributor SAW filter provided for each channel required for retransmission to be separated into band signals, each amplifier for amplifying each output signal of the SAW filter, a first mixer for synthesizing the output signal of each amplifier, and a first mixer A re-transmission unit having a pair of up-converters that convert the output signal of the output signal to the RF signal of the desired transmission channel, with the input connected to the second distributor and The connected to the second mixer, characterized in that arranged plurality of sets in parallel.

  One re-transmission unit is composed of a set of a plurality of continuous channels, and a terrestrial digital broadcast re-transmission apparatus as a whole is composed of an arbitrary number of combinations of the re-transmission units. Of course, the channel band assigned to each retransmission unit is different.

Here, the intermediate frequency band is composed of bands for three consecutive channels. That is, three consecutive channels are converted into an intermediate frequency band by one re-transmission unit as one band, and then processed for each channel. In the actual channel arrangement of Kanto, Kinki, and Chukyo, Kanto has 9 consecutive channels, and Kinki and Tokai also have 6 consecutive channels. By configuring the digital terrestrial broadcast retransmission apparatus with three retransmission units, the versatility can be improved. If versatility is not considered, the number of channels of one retransmission unit is not limited. Furthermore, SAW filters may be provided for all the plurality of channels (claim 2). That is, if it is necessary to retransmit signals of all continuous channels, a SAW filter is provided for each continuous channel. For example, if all three channels are used, SAW filters are provided at intervals of 6 MHz for three consecutive channels. In addition, the SAW filter may be provided for a part of channels to be retransmitted among a plurality of channels. For example, in the case of retransmitting signals of any two channels or any one channel in three consecutive channels, a SAW filter may be provided for that channel.

Further, the number of channels used by the retransmission unit of the terrestrial digital broadcast retransmission apparatus may be the same or different (claim 3 ). The number of channels retransmitted by one retransmission unit may be the same or different. For example, a certain retransmission unit may perform retransmission for all three channels, and another retransmission unit may perform retransmission for two channels or three channels of the three channels.

Of the plurality of retransmission units, at least one retransmission unit has a switch that can be switched between a terminal connected to the second distributor and a terminal that is not connected, and a terminal that is not connected to the second distributor when switching to mAY as a device for retransmitting a terrestrial Dijiruta broadcast signal of prefectural broadcasting (claim 4). For example, only one retransmission unit is separated from the second distributor by a switch. Then, the signal from the antenna that receives the wide area broadcast signal is input to the second distributor, and the signal from the antenna that receives the prefectural area broadcast signal is input to the separated retransmission unit. If it does in this way, each received signal from the antenna which receives a wide area broadcast signal and a prefectural area broadcast signal each independently can be outputted to a retransmission unit.

  In the present invention, only one downconverter and one upconverter are required for each retransmission unit. The inventor has noticed that the power consumption of the terrestrial digital broadcast retransmission apparatus is largely governed by the power consumption of the down converter and the up converter. For this reason, the idea was that if the number of down-converters and up-converters can be reduced as a whole of the terrestrial digital broadcast retransmission apparatus, the power consumption of the terrestrial digital broadcast retransmission apparatus can be reduced. For this purpose, in the terrestrial digital broadcast retransmitting apparatus, if a plurality of continuous channels are taken as one unit and the high frequency band is converted into an intermediate frequency band, the transmission signal level can be adjusted for each channel and the power consumption can be reduced. The inventors have invented that this can be reduced.

Thus, the present invention is provided with the respective retransmission unit for each band of three consecutive Ji Yaneru can reduce the number of down-converter and up-converter, can greatly reduce the power consumption of the terrestrial digital broadcast retransmission apparatus It was. In addition, each retransmission unit is provided with a SAW filter and an amplifier having different center frequencies for channels that require retransmission, so that the signal level to be retransmitted for each channel can be adjusted. Can do.

Also, or provided SAW filters for all channels in the band of the plurality of channels of continuous retransmission unit (claim 2), the number of used channels of retransmission unit, the same or to differ ( According to the third aspect of the present invention, it is possible to flexibly cope with different channel arrangements for each region. In particular, in the channel arrangement, even if the channels are not continuous, it is possible to associate the retransmission units for each continuous channel group as much as possible, and the number of retransmission units themselves can be reduced. it can. As a result, a device with reduced power consumption can be obtained for various channel arrangements.

According to the configuration of claim 4 , even when there is a wide area broadcast signal antenna and a prefectural area broadcast signal antenna, it is possible to cope with one terrestrial digital broadcast re-transmission device, thereby reducing power consumption. be able to.

Hereinafter, the present invention will be described based on specific examples. However, the present invention is not limited to the following examples.
FIG. 1 is a configuration diagram showing a television joint reception system used in difficult viewing areas and the like. A wide area terrestrial digital broadcast antenna 110, a prefectural terrestrial digital broadcast antenna 111 for receiving terrestrial digital broadcast signals, and an antenna 112 for receiving analog broadcast signals are provided. Signals received by the wide area terrestrial digital broadcast antenna 110 and the prefectural terrestrial digital broadcast antenna 111 propagate through the transmission path 113, and after the signal level of each channel is adjusted by the terrestrial digital broadcast retransmission apparatus 127, the attenuator It is output to 121. Further, the analog signal received by the antenna 112 propagates through the transmission path 114, the signal level of each channel is adjusted by the analog broadcast retransmitting device 125, and is output to the attenuator 122. Thereafter, these signals are mixed by the mixer 115 in the UHF band. The mixed signal of the terrestrial digital broadcast signal and the analog broadcast signal is amplified by the relay amplifiers 116a and 116b and distributed to each terminal 119 (television receiver) using the branching device 117, the branching device 118, and the like. . In the mixer 115, the terrestrial digital broadcast signal and the analog broadcast signal are mixed. Adjustment of the signal level of both signals is performed by adjusting the attenuation rate of the attenuator 121 and the attenuator 122. The terrestrial digital broadcast retransmitting device 127 and the analog broadcast retransmitting device 125 are supplied with power from the power supply device 123 via the power supply inserter 124.

In the transmission path 113 between the antennas 110 and 111 and the attenuator 121, a terrestrial digital broadcast retransmission apparatus 127 is provided. This terrestrial digital broadcast retransmitting device 127 (hereinafter referred to as “retransmitting device”) has the configuration shown in FIG.
The retransmission apparatus 127 includes two systems of RF input terminals, input terminals 27a and 27b. A TV signal from the wide area terrestrial digital broadcasting antenna 110 is input to the input terminal 27a. A TV signal from the prefectural terrestrial digital broadcasting antenna 111 is input to the input terminal 27b. Wide-area broadcast waves can be received together by a single antenna 110 because broadcast signals from a plurality of stations are transmitted from the same transmitting station. Since the signal input to the input terminal 27a includes unnecessary signals other than the UHF band television channel, a high-frequency signal in a band in which a 470-770 MHz terrestrial digital broadcast wave is propagated by the bandpass filter 28a. Extracted. The prefectural terrestrial digital broadcast signal is extracted by the bandpass filter 28b.

  The distribution compensation amplifier 29 compensates for a signal loss in the subsequent distributor 20 (second distributor). In particular, when the antenna reception level is low, it is effective in suppressing CN deterioration of the received signal. The signal distributed by the distributor 20 is input to the retransmission units 22a to 22e, and signal processing is performed by each retransmission unit. If the input signal selection switch 21 at the previous stage is connected to the terminal S1 side, the re-transmission unit 22e receives the wide-area terrestrial digital broadcast signal from the input terminal 27a. If the input signal selection switch 21 is connected to the terminal S2, the prefectural terrestrial digital broadcast signal from the input terminal 27b is input.

  The terrestrial digital broadcast signals output from the retransmission units 22a to 22e are mixed by the mixer 23 (second mixer), adjusted to an appropriate level by the variable attenuator 24 and the amplifier 25, and output from the output terminal 26. Is done.

  The configuration of one retransmission unit 22a is the configuration shown in FIG. In this example, continuous three-channel signals of 20 ch to 22 ch are processed at once. A signal from the distributor 20 is input to the input terminal 1. The signal includes unnecessary signals other than the terrestrial digital broadcast signal desired to be retransmitted. The bandpass filter 2 attenuates signals other than the channel for which retransmission is desired. The pass band width of the band-pass filter 2 is ensured to be 3 channels (18 MHz) or more which are continuous bands. The band pass filter 2 is composed of an LC circuit. The terrestrial digital broadcast signal extracted by the bandpass filter 2 is converted into an intermediate frequency band signal (hereinafter referred to as “IF signal”) by a down converter 13 constituted by a local oscillator 4 and a mixer 3. This IF signal is input to the intermediate signal processing circuit 14. The intermediate signal processing circuit 14 includes a distributor 17 (first distributor) that distributes IF signals in three, and three types of SAW filters 5a, each having a different center frequency of 6 MHz for extracting each distributed IF signal for each channel. 5b, 5c and gain control amplifiers (AGC) 6a, 6b, 6c for amplifying the output signals of the filters, respectively, and a mixer 18 (first stage) for mixing the outputs from the gain control amplifiers 6a, 6b, 6c. 1 mixer).

  The center frequencies of the SAW filters 5a, 5b, and 5c are 51, 57, and 63 MHz, respectively, and the oscillation frequency of the local oscillator 4 is set so that the center frequency of the 21ch input signal becomes the center frequency 57 MHz of the SAW filter 5b. Has been. Signal levels of the signals extracted for each single channel by each SAW filter are corrected by the gain control amplifiers 6a, 6b, and 6c. The AGC operation is always performed so that the signal level is constant.

  In the intermediate frequency signal processing circuit 14, the signal levels of the respective channels are aligned at a constant level, and are converted into RF signals of a desired transmission channel by the up-converter 15 including the local oscillator 8 and the mixer 7. At this time, when the channel band for retransmission is not changed, that is, when the same frequency pass-through is performed, the local oscillation frequency used by the up-converter 15 is the same as the oscillation frequency of the local oscillator 4. Therefore, the oscillation signal of the local oscillator 4 may be used without using the local oscillator 8.

  From the obtained RF signal, unnecessary signals (local oscillation frequency, image signal, etc.) other than a predetermined channel to be retransmitted are removed by the band-pass filter 9 at the subsequent stage.

  The terrestrial digital retransmission apparatus according to the present embodiment has the above-described configuration. An example of use of this terrestrial digital retransmission apparatus will be described. FIG. 4 shows the channel arrangement in each region. The wide-area TV signal in the Kanto region has 9 channels from 20 to 28 channels. Therefore, the 3 channels from 20ch to 22ch are processed by the retransmission unit U1, the 3 channels from 23ch to 25ch are processed by the retransmission unit U2, and the 3 channels from 26ch to 28ch are processed by the retransmission unit U3.

  The wide-area TV signal in the Kinki region is processed by the retransmission unit V1, 3 channels from 13ch to 15ch, the retransmission unit V2 by 3 channels from 16ch to 18ch, and the retransmission unit V3 by the retransmission unit V3. Like that. At this time, if the retransmission unit V3 has the same channel arrangement as the retransmission unit U2, the retransmission unit V3 includes only the SAW filter 5b in the retransmission unit 22a of FIG. 5a and 5c are not installed because the channel is not used.

In addition, a 14-channel single channel is processed by the retransmission unit W1, 3 channels from 18ch to 20ch are processed by the retransmission unit W2, and 3 channels from 21ch to 23ch are processed by the retransmission unit W3. To. At this time, if the retransmission unit W1 has the same channel arrangement as that of the retransmission unit V1, the retransmission unit W1 includes only the SAW filter 5a in the retransmission unit 22a of FIG. 5b and 5c are not installed because the corresponding channel is not used.

  In this manner, in the Kanto region, nine sets of down converters 13 and up converters 15 are required in the conventional apparatus, but there are three sets. As a result, when all nine waves are frequency-converted, the operating voltage of the device is 30V specification and the conventional device has a power consumption of 74VA. However, in this embodiment, the power consumption is 20VA. It was possible to greatly reduce the conventional 27%. Further, when the frequency of 9 waves is not converted (when the frequency of the local oscillator 4 of the downconverter 13 is used without using the local oscillator 8 of the upconverter 15), the conventional device has a power consumption of 69VA. In this example device, it was 17 VA, which was a great reduction to 25% of the conventional value.

  In the Kinki and Chukyo regions, seven sets of down converters 13 and up converters 15 are required in the conventional apparatus.

  In the present embodiment, the power consumption when performing frequency conversion is as follows. When the terrestrial digital broadcast re-transmission device is composed of one re-transmission unit, the power consumption of the device is 9.2 VA for the 30 V specification and 9.4 VA for the 60 V specification. When the terrestrial digital broadcast re-transmission apparatus is composed of two re-transmission units, the power consumption of the apparatus is 14.3 VA for the 30 V specification and 12.6 VA for the 60 V specification. The power consumption of the device in the case of 3 retransmission units is 19.2VA for the 30V specification and 15.4VA for the 60V specification. The power consumption of the apparatus when it is composed of 4 retransmission units is 19.4VA for the 24.1VA and 60V specifications when the operating voltage of the apparatus is 30V. The power consumption of the apparatus when it is composed of 5 retransmission units is 29.3VA for the 30V specification and 23.2VA for the 60V specification.

  Similarly, power consumption when frequency conversion is not performed is as follows. When the terrestrial digital broadcast re-transmission device is composed of one re-transmission unit, the power consumption of the device is 8.4 VA for the operation voltage of 8.4 VA and 60 V for the operation voltage of the device. When the terrestrial digital broadcast re-transmission apparatus is composed of two re-transmission units, the power consumption of the apparatus is 12.6 VA for the 12.6 VA and 60 V specifications for the operating voltage of the apparatus. The power consumption of the apparatus in the case of 3 retransmission units is 13.4 VA when the operating voltage of the apparatus is 30V specification, 16.8VA, 60V specification. The power consumption of the apparatus when it is composed of 4 retransmission units is 16.8 VA when the operating voltage of the apparatus is 30V specification and 20.9VA and 60V specification. The power consumption of the apparatus when it is composed of 5 retransmission units is 20.1 VA when the operating voltage of the apparatus is 30V specification and 25.0VA and 60V specification.

  As described above, in this embodiment, the power consumption can be greatly reduced in a state where the signal level of each channel can be adjusted independently.

  Also, in this embodiment, when the terrestrial digital broadcast retransmission apparatus is configured with a conventional repeater amplifier housing, the retransmission unit can be configured to be detachable, thereby incorporating the retransmission unit according to each region. Can do. In the present embodiment, since five retransmission units can be incorporated, it is possible to cope with all channels as long as one group can be divided into five groups or less with three continuous channels. FIG. 5 is a graph showing the ratio of the number of necessary units when using a retransmission unit with one set of three consecutive channels for the nationwide digital terrestrial broadcast channel arrangement. 97.7% can be handled with 5 units or less, and 89.4% can be handled with 4 units or less. That is, in this embodiment, 89.4% can correspond to two types of wide area broadcasting and prefectural area broadcasting.

  The present invention relates to a television joint reception system that receives a digital terrestrial broadcast signal and an analog broadcast signal by an antenna using spatial radio waves and supplies each terminal to each terminal via a transmission line, without adding a power feeding device. It can be used as a terrestrial digital broadcast retransmitting apparatus in which the transmission level of each channel of the digital broadcast signal is adjusted.

The block diagram of the television joint reception system which showed specific embodiment of this invention. The block diagram of the terrestrial digital broadcast re-transmission apparatus which showed specific embodiment of this invention. The block diagram of the terrestrial digital broadcast re-transmission unit mounted in the terrestrial digital broadcast re-transmission apparatus concerning the Example. Channel layout in each region. The graph which showed the ratio with respect to the whole number of retransmission parts with respect to the required number of terrestrial digital broadcast retransmission units.

Explanation of symbols

4, 8 ... Local oscillators 5a to 5c ... SAW filters 6a to 6c ... Gain control amplifier 13 ... Down converter 14 ... Intermediate frequency signal processing circuit 15 ... Up converter 17 ... Distributor (first distributor)
18 ... Mixer (first mixer)
20 ... distributor (second distributor)
21 ... Switch 22a-22e ... Retransmission unit 23 ... Mixer (second mixer)
DESCRIPTION OF SYMBOLS 110 ... Wide area terrestrial digital broadcasting antenna 111 ... Prefectural area terrestrial digital broadcasting antenna 112 ... Analog broadcasting antenna 113 ... Transmission path 115 ... Mixer 116a, 116b ... Relay amplifier

Claims (4)

In a terrestrial digital broadcast retransmission apparatus that receives a terrestrial digital broadcast signal and retransmits it to a predetermined area,
A down-converter for converting the 3-band Ji Yaneru worth of continuous of terrestrial digital broadcasting band in the intermediate frequency band,
A first distributor for distributing the output of the downconverter to the number of each channel;
A SAW filter provided for each channel necessary for retransmission, which separates the signal distributed by the first distributor into intermediate frequency band signals for each channel necessary for retransmission;
Each amplifier for amplifying each output signal of the SAW filter;
A first mixer for combining the output signals of the amplifiers;
A re-transmission unit having a set of an up-converter that converts an output signal of the first mixer into an RF signal of a desired transmission channel,
A terrestrial digital broadcast retransmission apparatus characterized in that an input is connected to a second distributor and an output is connected to a second mixer, and a plurality of sets are arranged in parallel. The SAW filter, terrestrial digital broadcasting retransmission apparatus of claim 1, characterized in that provided for all of the plurality of channels.   3. The terrestrial digital broadcast retransmission according to claim 1, wherein the number of channels used by each of the retransmission units of the terrestrial digital broadcast retransmission apparatus is the same or different. apparatus. Of the plurality of retransmission units, at least one retransmission unit has a switch that can be switched between a terminal connected to the second distributor and a terminal that is not connected, and is connected to the second distributor. The terrestrial digital broadcast retransmitting device according to any one of claims 1 to 3, wherein the terrestrial digital broadcast retransmitting device is a device that retransmits a terrestrial digital broadcasting signal for prefectural broadcasting when the terminal is switched to a terminal that does not .

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