JP2006014176A - Retransmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a retransmission technology of CATV facilities which makes a receiver reliably perform a channel registration after a frequency rearrangement, and optimizes the frequency rearrangement. <P>SOLUTION: When a physical channel is rearranged, a simultaneous period is provided for simultaneously retransmitting a desired channel in a first and a second physical channel, an interference signal is output to a frequency band of the first physical channel to be synthesized during the simultaneous period, and the output of the signal in the first physical channel and the interference signal to a transmission line is stopped after the simultaneous period. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a digital broadcast re-transmission apparatus, and more particularly to a re-transmission apparatus that performs frequency conversion and re-transmission of digital terrestrial television broadcasts.

  In recent years, satellite broadcasting and cable broadcasting (hereinafter referred to as CATV) are becoming widespread in addition to conventional terrestrial broadcasting that transmits program video to each home using radio waves in the VHF band and UHF band. Recently, standardization of digital broadcasting has been carried out, and digital broadcasting by a communication satellite (CS: Communications Satellite) (hereinafter referred to as CS digital broadcasting) and digital broadcasting by a broadcasting satellite (BS: Broadcasting Satellite) (hereinafter referred to as BS). Digital broadcasting) and broadband CS digital broadcasting are commercialized. In addition, terrestrial digital broadcasting started on December 1, 2003 in Tokyo, Nagoya and Osaka. Terrestrial digital broadcasting uses OFDM (Orthogonal frequency division multiplexing) as a modulation method, and can be transmitted with a bandwidth of 6 MHz of 1 RF channel as in the case of current analog television broadcasting. Since this bandwidth is the same in CATV which mainly retransmits the current analog television broadcast, it is also possible to transmit an OFDM terrestrial digital broadcast as it is to each home through the CATV transmission path. .

  One of the methods for transmitting such terrestrial digital broadcasting by CATV is a pass-through method. According to the Japanese cable lab specification "Digital Terrestrial Television Broadcasting Pass-through Operation Specification" JCL SPEC-006 1.0 Edition (Non-Patent Document 1), the pass-through method includes the same frequency pass-through operation method and the frequency conversion pass-through operation method.

  The same frequency pass-through operation method selects each terrestrial digital television broadcast signal of the terrestrial receiving antenna output, adjusts the level, and transmits the CATV facility at the same frequency as the broadcast signal (radio wave) frequency for all retransmitted channels. This is a transmission method.

  The frequency conversion pass-through operation method is a method in which each terrestrial digital television broadcast signal output from the terrestrial receiving antenna is selected, level-adjusted, and transmitted to the CATV facility at a frequency set by the CATV operator. FIG. 19 shows a conventional configuration example of the head end of the frequency conversion pass-through operation system CATV facility. In FIG. 19, reference numeral 1901 denotes a digital broadcast signal input terminal, 1902 denotes a signal distribution unit, 1903a to 1903d denote frequency conversion units, 1904 denotes a frequency multiplexing unit, and 1905 denotes a CATV signal output terminal.

  A digital broadcast reception signal is input from a digital broadcast signal input terminal 1901. This received signal is distributed by the signal distributor 1902 by the number of digital terrestrial broadcasts that can be received at the receiving point or the number of RF channels (physical channels) that are to be transmitted by this CATV equipment. A plurality of terrestrial digital broadcast UHF channels are converted into a plurality of different frequency bands by frequency converters 1903a to 1903d, respectively, and frequency-multiplexed by a synthesizer 1904. The frequency-multiplexed signal is transmitted to the CATV transmission line via the CATV signal output terminal 1905.

  FIG. 19 shows the frequency conversion of UHF14 channel of terrestrial digital broadcasting to 31 CATV channel, UHF16 channel of terrestrial digital broadcasting to 32 CATV channel, UHF17 channel of terrestrial digital broadcasting to 33 CATV channel, and UHF18 channel of terrestrial digital broadcasting to 34 CATV channel. An example is shown.

  As described above, the bandwidth of the 1 RF channel (physical channel) of the terrestrial digital broadcasting of the OFDM system is 6 MHz, which is the same in the CATV that mainly retransmits the current analog television broadcasting. The terrestrial digital broadcast can be directly converted into frequencies in units of RF channels at the head end of the CATV facility, and transmitted to each home through the CATV transmission path.

FIG. 20 is a block diagram showing a conventional example of a digital television broadcast receiving apparatus that receives a transmission signal from the head end of the CATV facility of FIG.
In FIG. 20, 2001 is an input terminal for a digital broadcast signal, 2002 is a tuner for physical channel tuning, 2003 is a demodulator for digital demodulation, and 2004 is TS separation for separating information from a transport stream (hereinafter referred to as TS). , 2005 is a video / audio decoding unit, 2006 is a video signal output terminal, 2007 is an audio signal output terminal, 2008 is a control unit of the digital broadcast receiving apparatus, 2009 is a channel selection control unit, and 2010 is for evaluating reception performance. It is a storage unit for storing a performance index.

  A digital broadcast signal input from the input terminal 2001 is sent to the tuner unit 2002. A tuner unit 2002 selects a necessary physical channel from a digital broadcast signal and converts it to an intermediate frequency. The demodulator 2003 receives this signal, performs digital demodulation, correction of data errors occurring in the transmission path, etc., and reproduces the TS. The video signal and audio signal data are separated from the TS reproduced by the TS separation unit 2004. The separated video signal and audio signal data is demodulated into a video signal and an audio signal by the video / audio decoding unit 2005, and the video signal is output to the video signal output terminal 2006 and the audio signal is output to the audio signal output terminal 2007.

The storage unit 2010 has a reception level determined from an automatic gain control signal (hereinafter referred to as AGC), a signal level such as C / N (carrier-to-noise) and S / N (signal level-to-noise), and equivalent noise (true In addition to the above noise, the storage unit stores a performance index such as a ratio of data transmission rate deterioration caused by phase noise or frequency spectrum disturbance to the performance deterioration due to noise level, and a data error rate.
The channel selection control unit 2009 controls the channel selection frequency supplied to the tuner unit 2002, data error correction in the demodulation unit 2003, demodulation of encoded information, TS separation in the TS separation unit 2004, and the like. The performance index information is extracted from each block, and the information is output to the storage unit 2010.

  The 2nd edition of “Technical Provisions for Digital Terrestrial Television Broadcasting” ARIB TR-B14 1.6 (Non-Patent Document 2), “National Terrestrial Television Broadcasting Receiver Function” According to the “specifications”, in the terrestrial digital television broadcast receiver, it is necessary to search all receivable channels at the reception point and create a service list based on service_id (hereinafter referred to as a receivable frequency table). It should be noted that a region where different physical channels can be received with the same network_id is assumed by MFN (Multi-Frequency Network: a network in which different frequencies are assigned to transmitting stations with overlapping service areas). C / N or BER (Bit Error Rate) Storing the good channels of the ratio of the number of bits) in "receivable frequency table". "a.

“However, since the received NIT (Network Information Table, which transmits transmission information such as frequencies) contains only the frequency transmitted from the broadcasting company's transmitting station, it is not possible to Even in this case, it is desirable that the receiver operates correctly, and it can be dealt with, for example, by giving priority to the “receivable frequency table”. "a.
A digital broadcast receiving apparatus which is a conventional example of FIG. 20 generally has this function.

At present, as for terrestrial television broadcasting, simultaneous broadcasting (simultaneous broadcasting) of analog terrestrial television broadcasting and digital terrestrial television broadcasting is performed, but terrestrial analog television broadcasting will be terminated on July 24, 2011. Is scheduled. At this time, so-called frequency repacking for changing the existing transmitting station frequency will be performed for the purpose of an optimal network configuration.
At present, CATV facilities transmit terrestrial digital television broadcasts by the pass-through method and distribute terrestrial analog television broadcasts. In particular, for broadcasters adopting the frequency conversion pass-through operation method, the possibility of optimizing the frequency arrangement as a CATV facility by changing the frequency arrangement of the terrestrial digital television broadcast after the terrestrial analog television broadcast is stopped. There is.

  Japanese Patent Laid-Open No. 2003-92743 (Patent Document 1) describes an example of a retransmission apparatus that can be switched to a standby system instantaneously when an abnormality or failure occurs. There is no description or suggestion of technology to make it possible.

JP 2003-92743 A Japan Cable Lab Specifications "Digital Terrestrial Television Broadcasting Pass-through Operation Specification" JCL SPEC-006 1.0 Edition The Japan Radio Industry Association technical data “terrestrial digital television broadcasting operation rules” ARIB TR-B14 1.6 edition

In a CATV facility that distributes digital broadcasts such as digital terrestrial television broadcasting by the pass-through method, in order to optimize the frequency arrangement as a CATV facility, it must be distributed at a frequency different from the frequency that has been distributed so far. There is. In this case, if it is a receiver such as a set top box (hereinafter referred to as STB) dedicated to CATV facilities, frequency relocation information is distributed to the STB in advance, and automatically when the date and time when the retransmitting side performs frequency relocation is reached. It is also possible to cause the STB to change the channel selection physical frequency and automatically follow the frequency relocation. However, when a current commercial receiver such as a terrestrial digital television broadcast receiver is receiving a CATV facility pass-through retransmission broadcast, it cannot automatically follow the frequency relocation. In general, when such frequency rearrangement is performed, the CATV operator notifies the subscriber of information such as the date and time of the frequency rearrangement and the target channel to the subscriber. Requests re-registration of channel registration by channel scan of receiver.
However, in the above-mentioned conventional technology, it is not possible to reliably perform channel registration after frequency rearrangement for current commercial receivers such as terrestrial digital television broadcast receivers. There is a possibility that the broadcast of the arranged physical channel cannot be received.

  In view of the situation of the above-described prior art, the problem of the present invention is that in the re-transmission technique, it is possible to make sure that the current commercial receiver can perform channel registration after frequency relocation, and the CATV facility. Even so, it is possible to optimize the frequency arrangement.

  In order to solve the above-described problems, in the present invention, a retransmission apparatus includes a receiving unit that receives a digital broadcast, a distributing unit that distributes an output signal of the receiving unit, and a desired channel from the output signal of the distributing unit. Extracting and transmitting the desired channel from the output signal of the first channel extraction and re-transmission unit that extracts and transmits to the transmission line at the frequency of the first physical channel before the rearrangement, and after the rearrangement A second channel extraction / retransmission unit that transmits to the transmission line at the frequency of the second physical channel, and an interference signal generation that outputs an interference signal to the transmission line in the frequency band of the first physical channel before the rearrangement. A physical period for retransmitting the desired channel simultaneously in the first physical channel and the second physical channel. A configuration in which the jamming signal is output to the frequency band of the first physical channel during the period, and the output of the signal in the first physical channel and the jamming signal to the transmission path is stopped after the end of the simulative period; To do.

  According to the present invention, even when a commercial TV receiver such as a terrestrial digital TV broadcast receiver receives a pass-through retransmission broadcast of a CATV facility, the channel registration of the receiver by channel scanning is performed. Channel registration after the frequency rearrangement can be surely performed only by redoing. For this reason, the receiver can receive the broadcast even after the frequency rearrangement is performed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiment, an example of a CATV facility that retransmits digital terrestrial television broadcasting by a frequency conversion pass-through operation method will be described.

FIG. 1 is a configuration block diagram of a re-transmission apparatus that shows a CATV head end as an embodiment of the present invention and performs frequency conversion and re-transmission of terrestrial digital broadcasting.
In FIG. 1, 101 is an antenna, 102 is a distribution unit, 103 is a signal processor unit (hereinafter referred to as SP unit) as a first channel extraction / retransmission unit, and subscripts a, b, c,. N represents the same function, and the number of physical channels to be retransmitted is N. Reference numeral 104 denotes an output signal of the frequency conversion unit 103. Subscripts a, b, c,..., N indicate outputs of the SP unit 103 having the same subscript. A combining unit 105 forms a first channel extraction / retransmission unit, similar to the SP unit 103. Reference numeral 106 denotes a transmission path, and 107 denotes a digital television broadcast receiver.

  Reference numeral 108 denotes a simulcast channel generator used for frequency rearrangement, and reference numeral 112 denotes an output signal of the simulcast channel generator 108. 109 is an additional SP unit as a second channel extraction / retransmission unit, 110 is an interference signal generation unit, 111 is a synthesis unit, and forms a second channel extraction / retransmission unit similar to the additional SP unit 109. The simulcast channel generation unit 108 includes an additional SP unit 109, an interference signal generation unit 110, and a synthesis unit 111.

First, a steady operation before frequency rearrangement is performed will be described.
The terrestrial digital broadcast is received by the antenna 101 set up in a place with good reception quality and input to the distribution unit 102. Distribution section 102 amplifies the received digital terrestrial television broadcast signal in all bands, distributes the necessary number of signals, and outputs the result to SP section 103. The SP unit 103 selects / extracts / adjusts the level of each physical channel from the terrestrial digital television broadcast signal of the entire band, converts it into a set frequency for CATV transmission, and outputs it to the combining unit 105. The combining unit 105 combines the physical channels selected by the respective SP units 103 and frequency-converted, and outputs the combined transmission signal to the transmission path 106. The digital television broadcast receiver 107 in each home receives and reproduces a desired channel from the transmission signal transmitted through the transmission path 106. The function of the digital broadcast receiving apparatus 107 is the same as that of the digital television broadcast receiving apparatus in FIG.

FIG. 2 is an explanatory diagram of frequency rearrangement in the embodiment of FIG. (A) is before change of frequency rearrangement, (b) is a simultaneous period, (c) shows after change of frequency rearrangement.
As an example of the frequency arrangement in the embodiment of FIG. 1, 201 is the frequency arrangement of the output signal 104a, UHF (hereinafter referred to as U) 14ch, 202 is the frequency arrangement of the output signal 104b, U16ch, 203 is the frequency arrangement of the output signal 104c. U17ch and 204 are U18ch in the frequency arrangement of the output signal 104N, and show the frequency arrangement before the frequency rearrangement change shown in FIG. Each is a different network_id.

Here, the frequency of U18ch network_id4 channel is rearranged to U15ch. In the case of frequency rearrangement, first, a simultaneous broadcasting simultaneous period is provided as shown in FIG. 205 is a U15ch signal after frequency rearrangement, and 206 is a U18ch signal before rearrangement. A signal 205 is an output signal 104N output by the SP unit 103N after frequency conversion from U18ch to U15ch. A signal 206 is an output signal 112 of the simulcast channel generator 108. The output signal 112 is a signal obtained by selecting, extracting, and adjusting the level of the same physical channel as the SP unit 103N from the terrestrial digital broadcast signal of the entire band by the additional SP unit 109. The interference signal from the signal generation unit 110 and the signal synthesized by the synthesis unit 111. The network_id of the output signal of the additional SP unit 109 is “4”, which is the same as the output signal 104N of the SP unit 103N.
After the end of the simulative period, as shown in FIG. 2C, the output signal 112 of the simulcast channel generation unit 108 is stopped and the signal 206 before the rearrangement is deleted to complete the frequency rearrangement.

  The digital television broadcast receiving apparatus 107 in FIG. 1 performs channel scanning according to a notification from the CATV provider during the simultaneous period in FIG. In general, all the channel information registered in the receiver is reset, and an initial scan for newly creating a channel list is performed. Thereby, the digital television broadcast receiving apparatus 107 selects the signal 205 instead of the signal 206 based on the performance index, and registers it in the channel list. The performance index refers to signal level such as C / N (carrier-to-noise) and S / N (signal level-to-noise) and equivalent noise (in addition to true noise, transmission path performance degradation due to phase noise, frequency spectrum disturbance, etc.) At least one of the ratio of the cause to the performance degradation due to the noise level) and the data error rate is used.

  The level of the interference signal from the interference signal generator 110 is determined by the value of the standard digital television receiver at the reference point on the transmission path. For example, in the case of the ratio between the signal level and the equivalent noise, the value of the signal 206 of the standard digital television receiver is not less than the value required for transmission (hereinafter referred to as required C / N) and not more than the value of the signal 205. The level of the interference signal from the interference signal generator 110 is adjusted so that It is conceivable that the interference signal level is about the median value (generally dB median value) between the value obtained from the signal 205 and the required C / N.

Also, for example, when using a data error rate, generally, a BER (Bit Error Rate) after Viterbi correction is used, and if it is 2 × 10 ⁻⁴ or less in a domestic terrestrial digital television broadcasting system Therefore, the level of the interference signal from the interference signal generator 110 is adjusted so that the value of the signal 206 of the standard digital television receiver is less than or equal to the value of the signal 205. It is conceivable to use a value obtained from the signal 205 and a center digit of 2 × 10 ⁻⁴ . Or simply may be adjusted from 1 digit 2 × ^{10 -4} between 2 decade (2 × ^{10 -5} units and between 2 × ^{10 -6} units).

  In the embodiment of FIG. 1, the simulcast channel generation unit 108 can easily adjust the interference signal level that is the output of the interference signal generation unit 110 and the output signal level of the additional SP unit 109.

  In the description of FIG. 1 and FIG. 2, only one physical channel is rearranged. However, when frequency rearrangement is performed on a plurality of physical channels, is it necessary to provide as many simulcast channel generators as there are rearrangements? Either rearrange the frequency of one physical channel after the reallocation of one physical channel with only one simulcast channel generation unit, or rearrange the required number of times, or compromise between the above two methods, that is, generate several simulcast channels It is possible to cope with this by rearranging the frequency of the number of physical channels using the unit and then performing the frequency rearrangement as many times as necessary.

FIG. 3 shows an example of a jamming signal from the jamming signal generator 110 in the simulcast channel generator 108 of FIG. In FIG. 3, 301, 302, 303, and 304 are carrier wave signals. In addition, the same reference numerals as in FIG. 2 indicate the same functions as in FIG.
In FIG. 3A, the jammed carrier signal 301 is added as a jam to the signal 206 before rearrangement. At this time, if the terrestrial digital television broadcast uses a partial reception layer, the fixed reception layer cannot be disturbed unless the partial reception layer is avoided. In addition, since the frequency interleaving is similarly applied to the layers other than the partial reception layer in the current operation regulations, the disturbing carrier signal 301 may be placed anywhere other than the partial reception layer.
FIG. 3B is a diagram in which the disturbing carrier signal 302 is multiplexed in the partial reception layer in addition to FIG. As a result, the technique of the present invention is effective for a receiver that receives only a partial reception layer.
FIG. 3C shows the disturbing carrier signal 303 at the position of the video carrier and the disturbing carrier at the position of the audio carrier when the analog television signal is transmitted in the frequency band (U18ch in this case) of the signal 206 before rearrangement. The signal 304 is multiplexed. As a result, the digital television broadcast receiver 107 determines that the analog television signal is mixed in the same channel and prevents the signal 206 before rearrangement from being selected by channel scanning.
In the jamming carrier signal from the jamming signal generator 110 in FIG. 3, at least one jamming carrier signal is only multiplexed. For this reason, the interference signal generator 110 can be configured simply.

FIG. 4 shows an example of a jamming signal from the jamming signal generator 110 in the simulcast channel generator 108 of FIG. In FIG. 4, 401, 402, 403, and 404 are modulated wave signals. In addition, the same reference numerals as in FIG. 2 indicate the same functions as in FIG.
In FIG. 4A, the disturbance modulated wave signal 401 is added as a disturbance to the signal 206 before rearrangement. At this time, if the terrestrial digital television broadcasting uses a partial reception layer, the fixed reception layer cannot be disturbed unless the partial reception layer is avoided. When multiplexing across partial reception layers, the frequency band of the partial reception layer needs to be sufficiently wider. It should be noted that the interfering carrier signal 401 may be placed anywhere other than the partial reception layer because frequency interleaving is similarly applied to the layers other than the partial reception layer in the current operational regulations.
FIG. 4B is a diagram in which the disturbing modulated wave signal 402 is multiplexed in the partial reception layer in addition to FIG. As a result, the technique of the present invention is effective for a receiver that receives only a partial reception layer. Note that the frequency band of the interfering modulated wave signal 402 is preferably narrower than the frequency band of the partial reception layer.
FIG. 4 (c) shows the disturbance modulated wave signal 403 at the position of the video carrier when the analog television signal is transmitted in the frequency band (here, U18ch) of the signal 206 before rearrangement, and the position of the audio carrier. The interfering modulated wave signal 404 is multiplexed. As a result, the digital television broadcast receiver 107 determines that the analog television signal is mixed in the same channel, and further prevents the signal 206 before rearrangement from being selected by channel scanning.
In the interfering modulated wave signal from the interfering signal generator 110 in FIG. 4, the terrestrial digital television broadcast signal is a multi-carrier OFDM system, but the degree of interference does not differ depending on the positional relationship with the multi-carrier.

FIG. 5 shows an example of a jamming signal from the jamming signal generator 110 in the simulcast channel generator 108 of FIG. Reference numeral 501 denotes a noise signal. The same reference numerals as in FIG. 2 indicate the same functions as in FIG.
FIG. 5A shows a case where only the output signal of the additional SP unit 109 in the simulcast channel generation unit 108 in FIG. 1 is output, and FIG. 5B shows the case in the simulcast channel generation unit 108 in FIG. FIG. 5C shows a case where only a noise signal that is an output signal of the interference signal generator 110 is output, and FIG. 5C shows an output signal of the simulcast channel generator 108.
In the noise signal from the interference signal generation unit 110 in FIG. 5, the C / N of the output signal of the simulcast channel generation unit 108 is obtained purely and can be easily compared with the required C / N.

FIG. 6 shows another configuration of the simulcast channel generator 108. Reference numeral 601 denotes an input terminal for the terrestrial digital television broadcast signal received from the distribution unit 102, 602 denotes an output terminal to the synthesis unit 105, and 603 denotes a distortion component generation unit. In addition, the same reference numerals as those in FIG. 1 denote parts having the same functions as those in FIG. The simulcast channel generation unit 108 includes an additional SP unit 109 and a distortion component generation unit 603.
FIG. 7 shows an example of distortion generation by the distortion component generation unit 603 in the simulcast channel generation unit 108 of FIG. The same symbols as those in FIG. 2 indicate the same function, 701 is a frequency pass characteristic, and 702 is an output signal of the simulcast channel generator 108.
FIG. 7A shows a case where only the output signal of the additional SP unit 109 in the simulcast channel generation unit 108 of FIGS. 1 and 6 is output. FIG. 7B shows the frequency pass characteristic of the distortion component generator 603, and the frequency characteristic is disturbed. The output signal of the additional SP unit 109 that has passed through this has a distorted frequency characteristic as shown in FIG.
In the simulcast channel generation unit 108 of FIG. 6, the signal 206 before rearrangement can be prevented from being selected by channel scanning with a simple configuration. Note that the frequency pass characteristic of FIG. 7B may be a characteristic different from 701, and the frequency band is not flat.

FIG. 8 shows another configuration of the simulcast channel generator 108. Reference numeral 801 denotes an intermediate frequency (hereinafter referred to as IF) converter, 802 denotes a distortion component generator, and 803 denotes an upconverter. In addition, the same code | symbol as the case of FIG. 1, FIG. 6 shows the part of the same function as each case.
The simulcast channel generation unit 108 in FIG. 8 converts the physical channel rearranged by the IF conversion unit 801 from the terrestrial digital television broadcast signal of the entire band from the input terminal 601 into an IF signal, and the distortion component generation unit 802 Distortion is generated, and the up-converter unit 803 converts the frequency into the CATV transmission frequency set before the rearrangement, and outputs it to the combining unit 105 from the output terminal 602.
FIG. 9 shows an example of the frequency pass characteristic of the distortion component generator 802 in the simulcast channel generator 108 of FIG. Reference numeral 901 denotes a frequency pass characteristic. The frequency pass characteristic 901 is a characteristic in the IF band, and the frequency characteristic is disturbed. The output signal of the distortion component generation unit 802 that has passed through this has a disturbed frequency characteristic, and the output signal of the up-converter unit 803 is also disturbed.
In the simulcast channel generation unit 108 of FIG. 8, only one IF band distortion component generation unit 802 can cope with the generation of distortion in the physical channel of the entire transmission band. Note that the frequency pass characteristic of FIG. 9 may be a characteristic different from 901, and the frequency band is not flat.

FIG. 10 shows another example of the distortion component generator 802 in FIG. Reference numeral 1001 denotes an input terminal from the IF conversion unit 801, 1002 denotes a processing unit, 1003 denotes a delay unit, 1004 denotes an addition unit, 1005 denotes a phase adjustment unit, and 1006 denotes an output terminal to the up-converter unit 803. In addition, the same reference numerals as those in FIG. 8 indicate parts having the same functions as those in FIG.
The IF signal from the input terminal 1001 is subjected to channel extraction / level adjustment by the processing unit 1002, delayed by the delay unit 1003, and input to the addition unit 1004. The adder 1004 adds the IF signal and the output signal from the delay unit 1003 and outputs the result to the phase adjustment unit 1005. The phase adjustment unit 1005 adjusts the phase and outputs it to the output terminal 1006.
FIG. 11 shows the frequency pass characteristic of the output signal from the output terminal 1002. Reference numeral 1101 denotes a frequency pass characteristic. The frequency pass characteristic 1101 shows a notch characteristic, the number of notches is changed by the delay amount of the delay unit 1003, and the attenuated frequency position is changed by the phase adjustment unit 1005. The amount of waveform distortion is adjusted by adjusting the position and the delay amount.
In the distortion component generation unit 802 in FIG. 10, the waveform distortion can be easily adjusted by adjusting the delay amount of the delay unit 1003 and the phase adjustment unit 1005.

FIG. 12 shows another configuration of the simulcast channel generation unit 108. 1201 is an IF conversion unit, 1202 is a phase noise generation unit, and 1203 is a processing unit. The same reference numerals as those in FIGS. 1, 6, and 8 indicate parts having the same functions as the respective cases.
12 converts a physical channel rearranged by the IF converter 1201 into an IF signal from the terrestrial digital television broadcast signal of the entire band from the input terminal 601 to an IF signal. 1202 degrades the phase noise performance by degrading the phase noise characteristics of the local transmitter, etc., the channel extraction / level adjustment is performed by the processing unit 1203, and the CATV transmission frequency set before relocation by the up-converter unit 803 And output from the output terminal 602 to the combining unit 105.
The simulcast channel generation unit 108 of FIG. 12 can generate distortion by a simple method of using the SP configuration and degrading phase noise during IF conversion.

FIG. 13 shows another configuration of the simulcast channel generation unit 108. 1301 is an up-converter unit, and 1302 is a phase noise generating unit. The same reference numerals as those in FIGS. 1, 6, and 8 indicate parts having the same functions as the respective cases.
13 converts a physical channel rearranged by the IF conversion unit 801 into an IF signal from the terrestrial digital television broadcast signal of the entire band from the input terminal 601, and extracts a channel by the processing unit 1203. When level adjustment is performed and the upconverter unit 1301 converts the frequency to the CATV transmission frequency set before the rearrangement, the phase noise generation unit 1302 causes the phase noise characteristic of the local transmitter to deteriorate, for example. Degrading performance. Thereafter, the data is output from the output terminal 602 to the combining unit 105.
The simulcast channel generation unit 108 of FIG. 13 can generate distortion by a simple method of using the SP configuration and degrading phase noise during up-conversion.

FIG. 14 shows a head end of a CATV as another embodiment of the present invention, and shows an example of the configuration of a retransmission apparatus that reconverts digital terrestrial broadcasting after frequency conversion.
In FIG. 14, 1401 is a combining unit, 1402 is an additional SP unit, 1403 is an output signal of the additional SP unit 1402, 1404 is an interference signal generation unit, and 1405 is an interference signal that is an output signal of the interference signal generation unit. In addition, the same reference numerals as those in FIG. 1 denote parts having the same functions as those in FIG.

  FIG. 15 is an explanatory diagram of frequency relocation in the case of the embodiment of FIG. The same reference numerals as those in FIG. 2 denote the same functions as those in FIG. FIG. 15A shows the frequency rearrangement before change, FIG. 15B shows the simultaneous period, and FIG. 15C shows the frequency rearrangement change. The steady operation before changing the frequency rearrangement in FIG. 15A is the same as in FIG. Similar to FIG. 2, the frequency of the U18ch network_id4 channel is rearranged to U15ch. In the case of frequency rearrangement, first, a simultaneous broadcasting simultaneous period is provided as shown in FIG. 205 is a U15ch signal after frequency rearrangement, and 206 is a U18ch signal before rearrangement.

In FIG. 15, the difference from the case of FIG. 2 is that the signal 205 is the output signal 1403 of the additional SP unit 1402, and the signal 206 is the output signal 104N of the U18ch of the SP unit 103N as in FIG. is there. The network_id of the output signal 1403 of the additional SP unit 1402 is “4”, which is the same as the output signal 104N of the SP unit 103N.
After the end of the simultaneous period, as shown in FIG. 15C, the output signal 104N of the SP unit 103N is stopped, the signal 206 before the rearrangement is deleted, and the frequency rearrangement is completed. The output signal 1405 of the interference signal generation unit 1404 is the same as the output signal of the interference signal generation unit 110 of FIG. 1 and is synthesized by the synthesis unit 1401 so that the examples of FIGS. Can do.

In the embodiment shown in FIGS. 14 and 15, only the SP unit and the interference signal generating unit which are normally used are added, and the configuration can be made inexpensive and simple.
14 and 15, only one physical channel is rearranged in frequency. However, when the frequency is rearranged in a plurality of physical channels, as many additional SP units and interference as are rearranged. Either a signal generation unit is provided, or one physical channel is rearranged with only one additional SP unit, and the remaining SP unit before rearrangement is used, and then frequency relocation is performed as many times as necessary. A compromise between the two methods, ie, using several additional SP units and jamming signal generation units, rearranging the frequency of the number of physical channels, and then using the remaining SP units before the rearrangement. This can be handled by performing as many frequency rearrangements as possible.

FIG. 16 shows the head end of a CATV that is another embodiment of the present invention, and shows the configuration of a retransmission apparatus that converts the frequency of digital terrestrial broadcasting and retransmits it. Reference numeral 1601 denotes a distortion component generation unit, and 1602 denotes an output signal of the distortion component generation unit 1601. The same reference numerals as those in FIGS. 1 and 14 indicate the same function as in each case.
16 is different from FIG. 14 in that the distortion component generator 1601 applies distortion to the output signal 1602 with respect to the output signal 104N of the SP unit 103N that is the signal 206 before rearrangement.
After the end of the simultaneous period, as shown in FIG. 15C, the output signal 104N of the SP unit 103N is stopped, the signal 206 before the rearrangement is deleted, and the frequency rearrangement is completed. The function of the distortion component generation unit 1601 is the same as the function of the distortion component generation unit 603 in FIG.
In the embodiment of FIG. 16, only the addition of the SP section and the distortion component generation section that are normally used are provided, and the configuration can be made inexpensive and simple. In the embodiment of FIG. 16, only one physical channel is frequency rearranged. However, when frequency rearrangement is performed on a plurality of physical channels, an additional SP section and distortion component generation section as many as the rearrangement are required. Or after rearranging one physical channel with only one additional SP part, and using the remaining SP part before rearrangement and subsequently rearranging the required number of frequencies, A compromise, i.e., using several additional SP units and distortion component generators to reallocate the number of physical channels, then use the remaining SP units before relocation, and then continue to the required number of frequencies. This can be done by rearranging.

FIG. 17 shows the head end of a CATV that is another embodiment of the present invention, and shows the configuration of a retransmission apparatus that converts the frequency of terrestrial digital broadcasting and retransmits it.
In FIG. 17, 1701 is a signal attenuating unit, and 1702 is an output signal of the signal attenuating unit 1701. In addition, the same reference numerals as those in FIG. 16 indicate the same functions as the respective cases. 17 differs from the case of FIG. 16 in that the level of the output signal 104N of the SP unit 103N, which is the signal 206 before rearrangement, is attenuated by the signal attenuating unit 1701 to be the output signal 1702. It is.

  FIG. 18 is an explanatory diagram of frequency rearrangement in the case of the embodiment of FIG. Reference numeral 1801 denotes an attenuated signal before the frequency rearrangement. In addition, the same reference numerals as in FIG. 2 indicate the same functions as in FIG. If the signal level of the pre-rearrangement signal 1801 is made relatively smaller than the signal 205 after the rearrangement, the digital television broadcast receiving apparatus 107 has a reception level determined from an automatic gain control signal (hereinafter referred to as AGC) or the like. The rearranged signal 205 can be reliably selected at the time of channel scanning.

  The attenuation amount of the signal attenuating unit 1701, that is, the output level of the output signal 1702 is determined by the value of the standard digital television receiver at the reference point on the transmission path. For example, a reception level determined from an automatic gain control signal (hereinafter referred to as AGC) or the like is greater than a value (hereinafter referred to as a minimum input level) required for transmission by a value of a signal 206 of a standard digital television receiver. , The attenuation amount of the signal attenuating unit 1701 is adjusted so as to be equal to or less than the value in the signal 205 to obtain the output level of the output signal 1702. It can be considered to be about the median value (generally dB median value) between the value obtained from the signal 205 and the minimum input level. In the embodiment of FIG. 17, an inexpensive and simple configuration in which only the signal level is attenuated can be achieved.

In the embodiment of FIG. 17, only one physical channel is rearranged. However, when frequency rearrangement is performed on a plurality of physical channels, an additional SP unit and signal attenuating units as many as the rearrangement are provided. Or, using only one additional SP part, rearrange the frequency of one physical channel and use the remaining SP part before the rearrangement, and subsequently rearrange the required number of frequencies, or a compromise between the above two methods That is, using several additional SP units and signal attenuating units, frequency relocation of the number of physical channels is performed, and the remaining SP units before relocation are used, and then frequency relocation is performed as many times as necessary. It can respond. In the embodiment of FIG. 17, the signal attenuating unit is a separate block for the sake of explanation. However, if the SP unit has a level adjustment function, this may be used.
If all the SP units in the CATV head end have the function of the simulcast channel generation unit 108, either the example of FIG. 2 or the example of FIG. 15 can be performed.

  According to each of the embodiments described above, in a CATV facility that distributes digital broadcasts such as terrestrial digital television broadcasts by the pass-through method, the frequency distribution is different from the frequencies that have been distributed so far in order to optimize the frequency arrangement as a CATV facility. Even when a commercial receiver such as a terrestrial digital television broadcasting receiver is used for distribution at a frequency, the subscriber can re-register the channel by performing a channel scan of the receiver by notifying the subscriber of the CATV operator. It is possible to make sure that the receiver performs channel registration after the frequency rearrangement by simply performing this. As a result, broadcast reception is possible after the frequency rearrangement as before.

  The present invention can be applied not only to the CATV facility of a CATV provider but also to a hearing system such as an apartment.

It is explanatory drawing of Example 1 of this invention, and is a figure which shows the head end of CATV. It is explanatory drawing of a frequency rearrangement. It is explanatory drawing of Example 2 of this invention, and is a figure which shows the example of a disturbance signal. It is explanatory drawing of Example 3 of this invention, and is a figure which shows the other example of a disturbance signal. It is explanatory drawing of Example 4 of this invention, and is a figure which shows the other example of a disturbance signal. It is explanatory drawing of Example 5 of this invention, and is a block diagram of a simulcast channel generation part. It is a figure which shows the example of distortion generation. It is explanatory drawing of Example 6 of this invention, and is a block diagram of a simulcast channel generation part. It is a figure which shows the example of a frequency passage characteristic. It is explanatory drawing of Example 7 of this invention, and is a block diagram of a distortion component generation | occurrence | production part. It is a figure which shows a frequency passage characteristic. It is explanatory drawing of Example 8 of this invention, and is a block diagram of a simulcast channel generation part. It is explanatory drawing of Example 9 of this invention, and is a block diagram of a simulcast channel generation part. It is explanatory drawing of Example 10 of this invention, and is a figure which shows the head end of CATV. It is explanatory drawing of a frequency rearrangement. It is explanatory drawing of Example 11 of this invention, and is a figure which shows the head end of CATV. It is explanatory drawing of Example 12 of this invention, and is a figure which shows the head end of CATV. It is explanatory drawing of a frequency rearrangement. It is a figure which shows the head end of the CATV as a prior art example. It is a figure which shows the digital broadcast receiver as a prior art example.

Explanation of symbols

101 ... antenna,
102 ... distribution part,
103 ... signal processor part,
105. Synthesis unit,
106 ... transmission line,
107: Digital television broadcast receiver,
108 ... simal channel generator,
109: Additional signal processor section,
110: Interference signal generator,
111 ... synthesis unit,
601... Input terminal for received digital terrestrial television broadcast signals of all bands,
602 ... Output terminal to the synthesis unit,
603 ... distortion component generation unit,
801: Intermediate frequency converter,
802 ... a distortion component generator,
803 ... up-converter part,
1001 ... Input terminal from the intermediate frequency converter,
1002 ... Processing unit,
1003 ... delay part,
1004 ... Adder,
1005 ... Phase adjustment unit,
1006: Output terminal to the up-converter unit,
1201 ... Intermediate frequency conversion unit,
1202 ... Phase noise generator,
1203... Processing unit,
1301... Upconverter section,
1302 ... Phase noise generator,
1401 ... synthesis unit,
1402 ... Additional signal processor section,
1404 ... Interference signal generator,
1601 ... distortion component generator,
1701 ... Signal attenuation unit,
1901: Digital broadcast signal input terminal,
1902: Signal distribution unit,
1903: Frequency converter,
1904: synthesis unit,
1905: CATV signal output terminal,
2001 ... Digital broadcast signal input terminal,
2002 ... tuner for selecting a physical channel,
2003 ... demodulator,
2004 ... Transport stream separation unit,
2005: Video / audio decoding unit,
2006 ... Video signal output terminal,
2007 ... Audio signal output terminal,
2008 ... Control unit of digital broadcast receiving device,
2009 ... Channel selection control unit,
2010: Storage unit.

Claims (3)

A re-transmission device that receives digital broadcasts, rearranges physical channels, and re-transmits them to a transmission path,
A receiver for receiving digital broadcasting;
A distributor for distributing the output signal of the receiver;
A first channel extraction / retransmission unit that extracts a desired channel from the output signal of the distribution unit and transmits the desired channel to the transmission line at a frequency of the first physical channel before rearrangement;
A second channel extraction / retransmission unit that extracts the desired channel from the output signal of the distribution unit and transmits it to the transmission line at the frequency of the second physical channel after the rearrangement;
An interference signal generator for outputting an interference signal to the transmission line in the frequency band of the first physical channel before the rearrangement;
With
When physical channel rearrangement is performed, a simultaneous period in which the desired channel is simultaneously retransmitted in the first physical channel and the second physical channel is provided, and the jamming signal is transmitted in the first period. The retransmission apparatus is characterized in that output to the frequency band of the physical channel is stopped, and output of the signal on the first physical channel and the interference signal to the transmission path is stopped after the end of the simultaneous period. A re-transmission device that receives digital broadcasts, rearranges physical channels, and re-transmits them to a transmission path,
A receiver for receiving digital broadcasting;
A distributor for distributing the output signal of the receiver;
A first channel extraction / retransmission unit that extracts a desired channel from the output signal of the distribution unit and transmits the desired channel to the transmission line at a frequency of the first physical channel before rearrangement;
A second channel extraction retransmission unit that extracts the desired channel from the output signal of the distribution unit and transmits the desired channel to the transmission line at the frequency of the second physical channel after the rearrangement;
A transmission path disturbance adding unit that adds a transmission path disturbance to the signal of the desired channel in the first physical channel before the rearrangement and outputs the transmission path disturbance to the transmission path;
With
When rearranging physical channels, a simultaneous period is provided in which the signal of the desired channel is simultaneously retransmitted in the first physical channel and the second physical channel, and the interference signal is transmitted during the simultaneous period. A retransmission apparatus that outputs to the frequency band of the first physical channel, and stops outputting the transmission path disturbance adder to the transmission path after the end of the simultaneous period. In a re-transmission device that receives digital broadcasts, rearranges physical channels and re-transmits them to the transmission path,
A first means for distributing the received digital broadcast;
A desired channel is extracted from the output signal of the distribution unit, transmitted to the transmission line at the frequency of the first physical channel before rearrangement, and transmitted to the transmission path at the frequency of the second physical channel after rearrangement. A second means to:
Third means for outputting an interference signal to the transmission line in the frequency band of the first physical channel before the rearrangement;
With
When physical channel rearrangement is performed, a simultaneous period in which the desired channel is simultaneously retransmitted in the first physical channel and the second physical channel is provided, and the jamming signal is transmitted in the first period. The retransmission apparatus is characterized in that output to the frequency band of the physical channel is stopped, and output of the signal on the first physical channel and the interference signal to the transmission path is stopped after the end of the simultaneous period.

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