JP2002217848A - Device and method for signal processing and digital broadcast signal distribution system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a digital broadcast signal whose C/N is sufficiently high. SOLUTION: A distributor 31 distributes an IF signal of a LNB to a remodulating part 32 for CH1, a remodulating part 35 for CH3, a remodulating part 38 for CH13 and a remodulating part 41 for CH15. The front end part 33 of the remodulating part 32 for CH1 extracts frequency components corresponding to a channel CH1 from the IF signal to demodulate the frequency component, and outputs a TS corresponding to the obtained channel CH1 to a modulating part 34. The modulating part 34 modulates the TS into an IF signal and outputs the IF signal to a multiplexing part 44. The multiplexing part 44 multiplexes the IF signal corresponding to channels CH1, CH3, CH13 and CH15 inputted from modulating parts 34, 37, 40 and 43 and outputs the IF signal to the distributor of a subsequent stage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal processing apparatus and method, and a digital broadcasting signal distribution system. Related to the distribution system.

[0002]

2. Description of the Related Art In apartment houses such as condominiums, BS (Broadcasting Satellite) broadcasts and CS (Communi
There is provided only one parabolic antenna for receiving a broadcast signal such as a cations satellite broadcast and distributing the received broadcast signal to each individual dwelling unit (so-called co-listening).

FIG. 1 shows an example of the configuration of a conventional system for listening to satellite broadcasts. In this system, the antenna 2 has a frequency of 11.71398 GHz to 12.0095 as shown in FIG.
0GHz BS broadcast wave and C from 12.250GHz to 12.7465GHZ
An S broadcast wave (hereinafter, referred to as an RF (Radio Frequency) signal) is received and supplied to an LNB (Low Noise Block) 3. LN
B3 converts the RF signal supplied from the antenna 2 into an IF (Intermediate Frequency) of a frequency band as shown in FIG.
The signal is frequency-converted and output to the distributor 5-1. The distributors 5-1 to 5-3 distribute the input IF signal and output it to a subsequent stage. The amplifiers 6-1 to 6-6 amplify the input IF signal and output it to a subsequent stage.

For example, the individual dwelling unit 1-1 has a distributor 5-
1 and amplified by the amplifier 6-1.
And the IF signal amplified by the amplifier 6-2 is distributed. The IF signal distributed to the individual dwelling unit 1-1 is distributed by the distributor 7-1, and the television receiver (BS TV) 8-1 with a built-in BS tuner and the set-top box (ST
B) Supplied to 9-1.

Similarly, the individual dwelling units 1-2 to 1-4 also have
An IF signal that has been repeatedly distributed and amplified is distributed.

For example, if the antenna 2 has a wide diameter (35
cm to 40 cm), LNB3
C / N (Carrier to Noise ratio) of IF signal output by
Is about 15 to 20 dB. In a device such as a set-top box 9-1 for receiving BS digital broadcast, a C / N ratio is set to display images stably.
Requires an IF signal of about 9 dB or more.

[0007]

As described above, distribution and amplification are repeated for the IF signals distributed to the individual dwelling units 1-1 to 1-4. C / N is deteriorated in comparison. In addition, the C of the IF signal may also be affected by reception impairment due to bad weather such as rainfall.
/ N deteriorates. Therefore, the set-top box 9
There has been a problem that the C / N of the IF signal supplied to -1 or the like is deteriorated from a required value, and a situation in which a stable image cannot be displayed may occur.

[0008] The present invention has been made in view of such a situation, and distributes and distributes IF signals corresponding to broadcast waves.
An object of the present invention is to prevent the C / N from being lower than a required value when the amplification is repeated.

[0009]

A signal processing apparatus according to the present invention comprises a plurality of data stream generating means for extracting a channel signal corresponding to a predetermined channel from a digital broadcast signal, demodulating the signal, and generating a data stream; The data stream generated by the stream generation means is encoded and modulated, converted to the same frequency as the channel signal, and a plurality of recovery means for recovering the channel signal is multiplexed with a plurality of channel signals recovered by the plurality of recovery means And multiplexing means for generating a signal corresponding to a digital broadcast signal.

A signal processing method according to the present invention includes a plurality of data stream generating steps for extracting and demodulating a channel signal corresponding to a predetermined channel from a digital broadcast signal to generate a data stream, and a data stream generating step. Encoding and modulating the generated data stream, converting it to the same frequency as the channel signal, and restoring the channel signal;
A multiplexing step of multiplexing a plurality of channel signals restored in the processing of the plurality of restoration steps to generate a signal corresponding to a digital broadcast signal.

According to the digital broadcasting signal distribution system of the present invention, a plurality of data stream generating means for extracting and demodulating a channel signal corresponding to a predetermined channel from the digital broadcasting signal to generate a data stream are provided. The generated data stream is encoded and modulated, converted to the same frequency as the channel signal, and a plurality of restoration means for restoring the channel signal, and a plurality of channel signals restored by the plurality of restoration means are multiplexed and digitally converted. It is characterized by including a signal processing device including multiplexing means for generating a signal corresponding to a broadcast signal, and a distribution means for distributing a signal corresponding to a digital broadcast signal.

In the signal processing apparatus and method of the present invention, a channel signal corresponding to a predetermined channel is extracted from a digital broadcast signal, demodulated to generate a data stream, and the generated data stream is encoded and modulated. Then, the channel signal is converted to the same frequency as the channel signal to restore the channel signal, and the restored channel signals are multiplexed to generate a signal corresponding to a digital broadcast signal.

In the digital broadcast signal distribution system of the present invention, a channel signal corresponding to a predetermined channel is extracted from the digital broadcast signal, demodulated to generate a data stream, and the generated data stream is encoded and modulated. Then, the channel signal is converted to the same frequency as the channel signal to restore the channel signal, and the restored channel signals are multiplexed to generate a signal corresponding to a digital broadcast signal. Further, a signal corresponding to a digital broadcast signal is distributed.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A satellite broadcast co-listening system to which the present invention is applied will be described with reference to FIG. This satellite broadcast co-listening system is a system for co-listening with satellite broadcasts, and in particular, suppresses deterioration of the C / N of BS digital broadcasts. This satellite broadcasting co-listening system is shown in FIG.
LNB 3 and distributor 5-1 in the conventional system shown in FIG.
, A satellite digital broadcast listening device 21 is additionally provided. The other components are common to the system of FIG. 1 and are given the same reference numerals.
The description is omitted.

The satellite digital broadcast listening device 21 is an LNB.
Of the IF signals (1035.98 MHz to 1331.50 MHz corresponding to the BS broadcast and 1214.322 MHz to 2068.50 MHz corresponding to the CS broadcast shown in FIG. 3) input from BS3, the channels CH1, CH3, CH13, And four channels of IF corresponding to CH15 and CH15, respectively.
Signal (bandwidth of each channel is 34.5MHz, center frequency is 1049.48MHz, 1087.84MHz, 1279.64MHz respectively
z or 1318.00 MHz), and MPEG (Moving Picture Experts Group) 2 corresponding to each channel
It restores the transport stream of the system (hereinafter, referred to as TS), and outputs to the distributor 5-1 an IF signal with an improved C / N modulated by the restored TS.

Here, terms such as channel CH1 correspond to each transponder of a broadcasting satellite.

FIG. 5 shows a satellite digital broadcast listening device 21.
3 shows a detailed configuration example. The distributor 31 converts the IF signal corresponding to the BS broadcast wave input from the LNB 3 into CH1
The re-modulation unit 32, the re-modulation unit 35 for CH3, the re-modulation unit 38 for CH13, and the re-modulation unit 41 for CH15 are distributed.

The front end unit 33 of the CH1 re-modulation unit 32 extracts a frequency component corresponding to the channel CH1 from the input IF signal, demodulates the frequency component, and outputs a TS corresponding to the obtained channel CH1 to the modulation unit 34. I do. The modulation section 34 modulates the IF signal by the TS input from the front end section 33 and outputs the modulated IF signal to the multiplexing section 44.

The front end unit 36 of the CH3 re-modulation unit 35 extracts a frequency component corresponding to the channel CH3 from the input IF signal, demodulates the signal, and outputs the obtained TS corresponding to the channel CH3 to the modulation unit 37. I do. The modulation section 37 modulates the IF signal by the TS input from the front end section 36 and outputs the IF signal to the multiplexing section 44.

The front end section 39 of the remodulating section 38 for CH13 converts the input IF signal into the channel CH13.
Is extracted and demodulated, and the TS corresponding to the obtained channel CH13 is output to the modulation unit 40. Modulating section 40 modulates the IF signal with the TS input from front end section 39 and outputs the result to multiplexing section 44.

The front end unit 42 of the remodulating unit 41 for CH15 converts the input IF signal into the channel CH15.
Is extracted and demodulated, and the TS corresponding to the obtained channel CH15 is output to the modulator 43. The modulation unit 43 modulates the IF signal by the TS input from the front end unit 42 and outputs the IF signal to the multiplexing unit 44.

The multiplexing section 44 corresponds to the IF signal corresponding to the channel CH1 input from the modulation section 34, the IF signal corresponding to the channel CH3 input from the modulation section 37, and the channel CH13 input from the modulation section 40. The multiplexed IF signal and the IF signal corresponding to the channel CH15 input from the modulation unit 43 are multiplexed and output to the subsequent-stage distributor 5-1.

The control unit 45 controls the drive 46,
Magnetic disk 47, optical disk 48, magneto-optical disk 4
9 or the control program stored in the semiconductor memory 50 is read out, and the entire satellite digital broadcast listening apparatus 21 is controlled based on the read out control program.

FIG. 6 shows an example of the configuration of the front end section 33. The tuner 51 extracts a frequency component corresponding to the channel CH1 from the input IF signal, and outputs it to the demodulation unit 52 as baseband signals I and Q. The demodulation unit 52 performs 8PSK (Phase Shift Keying) demodulation processing on the baseband signals I and Q input from the tuner 51, and then performs inner code decoding processing (Viterbi decoding processing), deinterleaving processing, descrambling processing, and An outer code decoding process (Reed-Solomon decoding process) is performed, and the obtained TS corresponding to the channel CH1 is output to the modulator 34.

The front end units 36, 39, 42
Also, the configuration is the same as that of the front end unit 33, and the description thereof is omitted.

FIG. 7 shows an example of the configuration of the modulation section 34. The encoder 61 performs an outer coding process, an energy spreading process, an interleaving process, and an inner coding process (a convolutional code) on the TS corresponding to the channel CH1 input from the demodulation unit 52 in synchronization with the clock signal CLK of the built-in oscillator. Baseband signals I and Q
Then, the used clock signal CLK is output to the 8PSK modulator 62.

The 8PSK modulation section 62 synchronizes with the clock signal CLK input from the encoder 61 and
Carrier (1st IF signal) corresponding to channel CH1 mapped to a phase as shown in FIG. 8 by subjecting baseband signals I and Q inputted from 1 to 8PSK modulation processing.
Is output to the frequency converter 63.

The frequency converter 63 includes an 8PSK modulator 6
The carrier corresponding to channel CH1 input from channel 2 is center frequency 1049.48 MHz corresponding to channel CH1.
To an IF signal having a bandwidth of 34.5 MHz and output to the multiplexing unit 44.

The modulators 37, 40, and 43 have the same configuration as the modulator 34, and a description thereof will be omitted.

Next, the operation of the satellite digital broadcast co-listening device 21 will be described with reference to the flowchart of FIG.

In step S1, the distributor 31 sets the LN
The IF signal corresponding to the BS broadcast wave input from B3 is
CH1 remodulation unit 32, CH3 remodulation unit 35, CH1
It is distributed to the re-modulation unit 38 for 3 and the re-modulation unit 41 for CH15.

In step S2, the tuner 51 of the front end unit 33 of the CH1 re-modulation unit 32 extracts a frequency component corresponding to the channel CH1 from the input IF signal, and demodulates it as baseband signals I and Q.
Output to

In step S 3, the demodulation section 52 adds the baseband signals I and Q input from the tuner 51 to 8
A PSK demodulation process is performed, an inner code decoding process is performed in step S4, a deinterleave process is performed in step S5, a descrambling process is performed in step S6, and an outer code decoding process is performed in step S7. , T corresponding to the obtained channel CH1
S is output to the modulator 34.

In step S 8, the encoder 61 of the modulating section 34 sets the channel C input from the demodulating section 52
Clock signal of the built-in oscillator in TS corresponding to H1
An outer encoding process is performed in synchronization with the CLK, an energy spreading process is performed in step S9, an interleaving process is performed in step S10, and furthermore, a step S11 is performed.
, An inner encoding process is performed, and the obtained baseband signals I and Q are output to the 8PSK modulation unit 62.

In step S12, the 8PSK modulator 6
2 is a channel C obtained by subjecting the baseband signals I and Q input from the encoder 61 to 8PSK modulation processing.
The carrier (1st IF signal) corresponding to H1 is output to the frequency converter 63. In step S13, the frequency converter 63 converts the carrier corresponding to the channel CH1 input from the 8PSK modulation unit 62 into a 34.5 MHz bandwidth having a center frequency of 1049.48 MHz corresponding to the channel CH1.
The signal is converted into an IF signal of z and output to the multiplexing unit 44.

In steps S2 to S13, the re-modulation unit 35 for CH3, the re-modulation unit 38 for CH13,
The 15CH1 remodulation unit 41 also executes the same processing as the processing of the CH1 remodulation unit 32 described above.
Therefore, the multiplexing unit 44 includes the channels CH1 and C
I corresponding to H3, CH13 and CH15
The F signal will be input.

In step S14, the multiplexing unit 44
Are the channels CH1, CH3, CH13, and CH
15 are multiplexed and output to the subsequent distributor 5-1.

As described above, in the satellite digital broadcast co-listening device 21, of the IF signals input from the LNB 3, the BS digital broadcast channels CH1, C
H3, 4 corresponding to CH13 and CH15, respectively
The IF signals for the channels are demodulated, the TS corresponding to each channel is restored, and the restored TS
Since the F signal is modulated, the C / N of the IF signal can be greatly improved.

For example, the C / N of the IF signal supplied by the LNB 3 to the satellite digital broadcast listening device 21 in fine weather
Is between 15 dB and 18 dB, but the C / N of the IF signal supplied from the satellite digital broadcast listening device 21 to the distributor 5-1 is about 50 dB.

Therefore, even if the distribution and amplification are repeated in the distributor 5-1 and thereafter, C required by the STB 9-1 or the like is required.
/ N (about 9 dB) can be supplied.

The present invention is not limited to BS digital broadcasting, but can be applied to CS digital broadcasting and terrestrial digital broadcasting as well as all kinds of digital broadcasting.

The series of processes described above can be executed by hardware, but can also be executed by software. When a series of processing is executed by software, a program constituting the software can execute various functions by installing a computer built into dedicated hardware or installing various programs. It is installed from a recording medium into a possible general-purpose personal computer or the like.

As shown in FIG. 5, the recording medium is a magnetic disk 47 (including a floppy disk) on which the program is recorded and an optical disk 48, which are distributed separately from the computer to provide the user with the program.
(CD-ROM (Compact Disc-Read Only Memory), DVD (Digit
al Versatile Disc), magneto-optical disc 49 (M
D (including Mini Disc)), or a packaged medium including the semiconductor memory 50, etc., and also provided to the user in a state in which the program is incorporated in advance in a computer. It is composed of

In this specification, the steps of describing a program recorded on a recording medium are not limited to processing performed in chronological order according to the described order, but are not necessarily performed in chronological order. Alternatively, it also includes individually executed processing.

In this specification, the system is
It represents the entire device composed of a plurality of devices.

[0046]

As described above, according to the signal processing apparatus and method of the present invention, a data stream corresponding to a predetermined channel is generated from a digital broadcast signal, the generated data stream is encoded and modulated, The channel signal is restored by converting it to the same frequency as the signal, and furthermore, the restored channel signals are multiplexed to generate a signal corresponding to a digital broadcast signal. It is possible to generate a digital broadcast signal whose C / N does not fall below a required value.

Further, according to the digital broadcast signal distribution system of the present invention, a data stream corresponding to a predetermined channel is generated from the digital broadcast signal, and the generated data stream is encoded and modulated to have the same frequency as the channel signal. To restore the channel signal, and further multiplex the restored plurality of channel signals to generate a signal corresponding to the digital broadcast signal and distribute the signal corresponding to the digital broadcast signal.
/ N digital broadcast signals can be supplied.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of a conventional system for co-listening to satellite broadcasting.

FIG. 2 is a diagram illustrating a frequency band of an RF signal.

FIG. 3 is a diagram illustrating a frequency band of an IF signal.

FIG. 4 is a block diagram illustrating a configuration example of a satellite broadcast co-listening system to which the present invention has been applied.

FIG. 5 is a block diagram showing a detailed configuration example of the satellite broadcast co-listening device 21.

6 is a block diagram illustrating a configuration example of a front end unit 33. FIG.

FIG. 7 is a block diagram showing a configuration example of a modulation unit 34.

FIG. 8 is a diagram for explaining 8PSK modulation processing.

FIG. 9 is a flowchart illustrating the operation of the satellite broadcast co-listening device 21.

[Explanation of symbols]

31 distributor, 32 CH1 remodulation section, 33 front end section, 34 modulation section, 35 CH3 remodulation section, 36 front end section, 37 modulation section,
38 CH13 remodulation section, 39 front end section, 40 modulation section, 41 CH15 remodulation section,
42 front end section, 43 modulation section, 44 multiplexing section, 45 control section, 46 drive, 47
Magnetic disk, 48 optical disk, 49 magneto-optical disk, 50 semiconductor memory

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H04N 5/455 H04N 5/455 7/08 7/10 7/081 7/20 630 7/10 7/08 Z 7/20 630 F term (reference) 5C025 AA15 AA27 AA28 DA01 DA04 5C056 FA02 FA08 FA11 GA11 HA01 HA14 5C063 AB03 AB06 AC01 CA40 DA01 DA13 5C064 BA02 BB05 BC12 BC14 BC21 BD08 5K022 AA04 AA12 AA31

Claims (3)

[Claims] 1. A plurality of data stream generating means for extracting and demodulating a channel signal corresponding to a predetermined channel from a digital broadcast signal to generate a data stream, and encoding the data stream generated by the data stream generating means. A plurality of restoring means for restoring the channel signal by converting the channel signal into the same frequency as the channel signal, and multiplexing the plurality of channel signals restored by the plurality of restoring means, Multiplexing means for generating a signal corresponding to the signal. 2. A plurality of data stream generating steps for extracting and demodulating a channel signal corresponding to a predetermined channel from a digital broadcast signal to generate a data stream, and the data generated in the processing of the data stream generating step A plurality of restoration steps for encoding and modulating a stream, converting the stream to the same frequency as the channel signal, and restoring the channel signal, and multiplexing the plurality of channel signals restored in the processing of the plurality of restoration steps And multiplexing to generate a signal corresponding to the digital broadcast signal. 3. A plurality of data stream generating means for extracting and demodulating a channel signal corresponding to a predetermined channel from a digital broadcast signal to generate a data stream, and encoding the data stream generated by the data stream generating means. A plurality of restoring means for restoring the channel signal by converting the channel signal into the same frequency as the channel signal, and multiplexing the plurality of channel signals restored by the plurality of restoring means, A digital broadcast signal distribution system, comprising: a signal processing device including multiplexing means for generating a signal corresponding to a signal; and distribution means for distributing the signal corresponding to the digital broadcast signal.