JPH04291589A - Subscription broadcasting decoder - Google Patents

Abstract

PURPOSE:To obtain a inexpensive and high-definition television subscription broadcasting decoder by providing a sound and video descrambling device, a re-MUSE sound encoding device and a device to multiplex the sound data to a video signal. CONSTITUTION:A PN signal outputted from a descrambling unit 6 and a scrambled sound data bit stream is added and descrambled by an exclusive OR device 7, and the scrambling-related bit is erased by an erasing device 43. Then, the encoding processing of the sound data rate conversion is performed by a MUSE sound encoding device consisting of a 16 bit interleave 41 and a 12.5MHz/16.2 MHz re-sampling waveform shaping filter 47. By re-multiplexing into the vertical blanking of a MUSE signal including the de-scrambled video signal, the inexpensive and high-definition decoder to handle the MUSE signal after scrambling is released, as a non-scrambling signal is obtained.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to high-definition television (
MUSE method=Multiple Sub-Nyqu
ist Sampling Encoding (Multiple Sampling Encoding) System (Developed by NHK) In pay broadcasting, this relates to a pay broadcast decoder that allows only contracted subscribers to unscramble and view programs.

0002

2. Description of the Related Art In recent years, paid broadcasting has been put into practical use with the expansion of broadcasting satellites. Unlike conventional broadcasting formats that rely on advertising fees and license fees, paid broadcasting requires programs to be delivered only to contracted receivers, so programs are usually disrupted electrically (
scrambled) and broadcast. For this reason, in order to view a pay broadcast program, a pay broadcast decoder is required to de-scramble and normally view the program.

Conventionally, multiple sampling coding (hereinafter referred to as M
As a pay broadcast decoder for signals (referred to as USE), a method has been considered in which a pay broadcast unit is incorporated in a MUSE decoder. On the other hand, as for the existing MUSE decoder, an independent MUSE pay broadcast decoder is being considered which connects the unscrambled video signal and audio signal separately. This means that the video signal in the MUSE signal is unscrambled and then D/A converted.
Since it is connected to the MUSE decoder, the audio signal in the audio signal area during vertical blanking is scrambled, but after the audio signal is descrambled, it is returned to an analog baseband signal for each channel.
It is connected to a MUSE decoder or VTR in an analog signal state. Therefore, in a MUSE decoder or VTR, when an independent MUSE pay-TV decoder is connected, the audio from this external input audio signal side is always selected and output, so that the audio during vertical blanking is not played back. In this case, normal descrambled audio is obtained.

An example of the above-mentioned conventional independent MUSE pay broadcast decoder will be described below with reference to the drawings.

FIG. 6 is a block diagram showing the connection between a conventional MUSE pay broadcast decoder and a MUSE decoder. In FIG. 6, reference numeral 2 denotes a MUSE signal input terminal of an independent MUSE pay broadcast decoder, into which normally a scrambled MUSE signal is input. 3 is an A/D converter that converts the analog MUSE signal into a digital MUSE signal 19; Reference numeral 4 denotes a clock and synchronization playback unit which outputs a digital signal processing reference clock of 16.2 MHz (hereinafter referred to as VCK) from the digital MUSE signal 19 and analog MUSE signal 2, and a video horizontal synchronization signal (hereinafter referred to as HD) necessary for each part of the independent MUSE pay broadcast decoder. ), the video frame synchronization signal (hereinafter referred to as VFRAM) is reproduced and supplied to each part within the independent MUSE pay broadcast decoder. 5 is an audio processing unit which reproduces an audio data bit stream 13 (hereinafter referred to as DBS) after 16-bit deinterleaving at a rate of 1.35 MHz from the digital MUSE signal, and also reproduces an audio data bit stream 13 (hereinafter referred to as DBS) as an audio data standard. A clock of 1.35 MHz (hereinafter referred to as ACK) is supplied to each part. 6 is a descrambling unit and DBS1
Take out the scramble related information from 3 and based on this,
A pseudo-random signal (hereinafter referred to as PN signal) 11 is used to descramble a scrambled digital MUSE signal 19 and output a descrambled MUSE signal 12, and to descramble the scrambled audio data bit stream 13 by adding the scrambled digital MUSE signal 19. occurs. 7 is an exclusive OR element which outputs a descrambled DBS 15 by performing an exclusive OR of the DBS 13 and the PN signal 11 for descrambling. 8 is the DBS15 descrambled by the audio processing section.
USE audio decode processing and output 4 channels of analog baseband audio before audio selection. A D/A converter 10 converts the digital MUSE signal 12, in which the video signal portion has been descrambled, into an analog signal.

Next, on the MUSE decoder side, 20
The A/D converter converts the analog MUSE signal whose video signal portion is descrambled into a digital MUSE signal. 21 is a MUSE video signal processing unit that performs MUSE decoding processing and outputs a high-definition monitor input signal such as a GBR signal from a digital MUSE signal. 22 is M
The USE audio processing section extracts the audio signals multiplexed during the blanking period of the MUSE signal to obtain an analog baseband audio signal 32 before audio selection. 31 is audio selection information, which is output based on the mode of multiplexed audio. 23 is an analog switch that connects either the external audio input signal/internal audio signal 32 to the input signal to the audio selection block. 24 is an external/internal selection switching signal input terminal for audio, which controls the analog switch 23 from the outside. Reference numeral 26 denotes an audio selection signal input terminal which is operated by the user to select audio during bilingual broadcasting, for example. 25 is an audio selection block based on selection information 31 based on the audio mode,
Each audio channel is appropriately selected and supplied to each speaker according to the audio selection signal 26. Reference numeral 27 indicates L, R, C, and S audio signals after audio selection, which are connected to each speaker via an amplifier or the like, and 30 indicates a video input signal to the high-definition monitor.

The operation of the independent MUSE pay broadcast decoder configured as described above will be explained below.

[0008] Both video and audio are scrambled M
Taking the case where a USE signal is input to an independent MUSE pay broadcast decoder as an example, for the video signal area of the MUSE signal input to the independent MUSE pay broadcast decoder, scramble related information in the DBS 13 from the audio processing unit 5 is used. After being descrambled by the descrambling unit 6 based on the
Connected to the MUSE decoder as a signal. Regarding the audio signal, first, the audio processing unit 5 extracts the audio signal from the audio signal area during vertical blanking of the MUSE signal 19, performs MUSE audio decoding processing halfway, and converts the audio signal into a scrambled 1.35 Mbit/sec. The audio data bit stream DBS13 is obtained. Then, the descrambling unit 6 uses a PN to descramble the DBS 13 based on the scrambling related information in the DBS 13.
The signal 11 is output, and the exclusive OR element 7 outputs DBS1.
The audio data bitstream DBS13 is descrambled by exclusive ORing with 3. Furthermore, the DBS 15 is descrambled by the audio processing unit 8.
is converted into an analog baseband audio signal before audio selection, and in this state is connected to the MUSE decoder as shown in the figure.

Next, in the MUSE decoder, only the input video signal region is descrambled, and the MUSE signal in which the audio portion is scrambled is digitally converted via the A/D converter 20 and sent to the MUSE video signal processing section. MUSE of the video part descrambled by 21
Decoding processing is performed and the video is played back on a high-definition monitor. On the other hand, for audio signals, in this case MU
Since the audio signal in the audio signal region during vertical blanking of the MUSE signal input to the SE decoder is in a scrambled state, the output 32 of the MUSE audio decoder 22 is in a scrambled state. However, since the audio mode bit area in the scrambled audio DBS is always in an unscrambled state, the audio selection information 31
is valid. Therefore, normally, when the independent MUSE pay-TV decoder is connected, the signal applied to the audio external/internal switching control input terminal 24 is set to the external audio side by manual operation etc., and the audio selection section 25 selects Based on the information 31, descrambled audio is reproduced by appropriately selectively supplying the analog audio input from the independent MUSE pay broadcast decoder to each speaker.

0010

However, the independent MUSE pay broadcast decoder with the above configuration descrambles the audio by performing PN addition on the audio data bitstream, and then converts the descrambled audio signal into an analog signal. Since the system converts to baseband and connects to the subsequent MUSE decoder, it has the following problems.

1) Since the audio data area during vertical blanking of the analog MUSE signal including the descrambled MUSE video signal output from the independent MUSE pay broadcast decoder remains scrambled, the independent MUSE pay broadcast decoder In the subsequent MUSE decoder, the audio data during vertical blanking is normally transferred to the MU.
SE audio cannot be decoded. This means that MUSEVT
We request R to provide new functions such as independent 4-channel audio tracks for recording and playing back programs that have been descrambled from scrambled broadcasts.

2) Scrambling related information remains in the independent data area of the audio data area during vertical blanking. This scramble-related information includes not only the information for unscrambling but also information such as billing processing for pay TV, so once the descrambling process is performed, the
When recorded by a USEVTR or the like and later played back by an independent MUSE pay-TV decoder or a MUSE decoder with a built-in pay unit, normal operation is not guaranteed.

3) The audio signal descrambled by the independent MUSE pay broadcast decoder is separated from the video signal by 4
Because each channel is connected to the MUSE decoder independently,
A large number of signal lines are required for connection.

4) Since the audio after descrambling is connected in an analog state to the MUSE decoder at the subsequent stage, the audio quality deteriorates.

[0015] The present invention solves the above-mentioned problems by allowing the unscrambled MUSE signal of pay broadcasting to be treated in the same way as a normal unscrambled signal, that is, by making it easy to connect with a MUSE decoder, and adding new functions to the MUSE VTR. To provide an independent MUSE pay broadcast decoder that eliminates the need for connection and does not cause deterioration in sound quality due to connection.

[0016]

[Means for Solving the Problems] In order to achieve the above object, the independent MUSE pay broadcast decoder of the present invention has a scrambling related information bit erasing section in an audio data bit stream, and a MUSE audio encoding processing section.
6-bit interleaving, BCH (82, 74) error correction code addition, 25 frame interleaving, time axis compression, binary and ternary conversion, 12.15MHz to 16.2MHz
This system adopts and combines a transversal filter for converting the audio data rate into the video signal, a delay circuit for adjusting the timing of multiplexing the encoded audio signal with the video signal, and a multiplexing circuit for the audio data during the vertical blanking period.

[0017]

[Operation] According to the above-described structure, the scrambled audio data bit stream is descrambled by the PN signal outputted from the descrambling unit, and after erasing bits related to scrambling, 16-bit interleave, BCH (82, 74) Add error correction code, 2
Performs MUSE audio encoding processing of 5-frame interleaving, time axis compression, binary-to-ternary conversion, and audio data rate conversion from 12.15MHz to 16.2MHz, and performs vertical blanking of MUSE signals including descrambled video signals. By re-multiplexing, the descrambled MUSE signal of pay broadcasting can be treated in the same way as a normal non-scrambled MUSE signal.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. (FIG. 1) shows the configuration of a MUSE pay broadcast decoder in one embodiment of the present invention.

In (FIG. 1), 2 is an analog MUSE
A scrambled MUSE signal is normally input to the signal input terminal. 3 is an A/D converter, analog MUS
Converts the E signal to a digital MUSE signal. 4 is a clock and synchronization playback section, which converts the digital MUSE signal into a digital signal processing reference clock of 16.2 MHz (hereinafter referred to as VCK), a video horizontal synchronization signal (hereinafter referred to as HD) necessary for each part of the independent MUSE pay broadcast decoder, and video An independent M
Supplied to various parts within the USE pay broadcast decoder. Reference numeral 5 denotes an audio processing unit which reproduces an audio data bit stream (hereinafter referred to as DBS) after 16-bit deinterleaving at a rate of 1.35 MHz from the digital MUSE signal, and also reproduces an audio data standard using an audio frame synchronization signal (hereinafter referred to as FSY). A clock of 1.35 MHz (hereinafter referred to as ACK) is supplied to the descrambling unit. 6 is a descrambling unit which extracts scramble-related information from the DBS 13, descrambles the scrambled digital MUSE signal 19 based on this, outputs a descrambled MUSE signal 12, and adds scrambled audio data bits. stream 1
A pseudorandom signal (hereinafter referred to as PN) for unscrambling No. 3 is generated. 7 is an exclusive OR element D
The D signal is descrambled by exclusive ORing the BS13 and the PN signal 11 for descrambling.
Output BS15. Reference numeral 43 denotes a scramble-related information bit erasing unit that erases information bits related to scrambling multiplexed in the DBS 15. Reference numeral 41 denotes a bit interleaving unit which re-interleaves the 16-bit deinterleaving performed by the audio processing unit 5. 42 is BCH (82,
74) An error correction code addition device adds 8 error correction bits to the 74 information bits in each row of the bit interleave matrix, excluding the descrambled synchronization signal and control code bits of the DBS 15. 44 performs interleaving between 25 audio frames based on the vertical blanking period in the MUSE signal multiplexed in the 25 audio frame interleaving section. Reference numeral 45 denotes a time axis compression unit which converts audio data at a rate of 1.35 MHz into burst data for multiplexing within the vertical period of the MUSE signal. Reference numeral 46 denotes a binary/ternary value conversion unit which converts continuous binary and 3-value data into two consecutive 3-value samples. 47 is a conversion filter, which compresses the time axis and performs binary/ternary conversion.
．． Frequency conversion is performed to match the 15MBaud audio data to the video signal sample rate of 16.2M rate. Reference numeral 48 denotes an encoded audio signal delay circuit that delays and adjusts the encoded audio signal to the timing of the vertical retrace interval audio multiplex region of the video signal output from the descrambling unit 6. Reference numeral 49 denotes an audio multiplexing timing control unit that outputs a signal indicating the audio multiplexing area during the vertical retrace period of the output MUSE signal from the descrambling unit 6. Reference numeral 50 denotes a signal changeover switch that switches between the output from the descrambling unit 6 and the output from the audio data time axis compressor 47 based on the output signal from the audio multiplexing timing controller 49. 51 is D
/A converter converts digital MUSE signal to analog MUS
Convert to E signal. 52 is the MUSE signal output terminal;
Connected to USE decoder and MUSE VTR.

The operation of the MUSE pay broadcast decoder configured as described above will be explained using the following (FIG. 1). MUS with scrambled video and audio
The explanation will be given by taking as an example the case where the E signal is input. The input MUSE signal is digitally converted by the A/D converter 3 and supplied to the descrambling unit 6, the audio processing section 5, the clock, and the synchronous reproduction section 4. Descrambling processing is performed as follows. First, the descrambling unit 6 extracts and decodes the scramble-related information in the DBS 13 from the audio processing section 5. (FIG. 4) shows the location of scramble-related information. (Figure 4) shows the bit allocation when multiplexing A-mode signals, the multiplexing position of scramble-related information, and DBS1.
FIG. 3 is an audio frame configuration diagram showing bit allocation in three states. As shown by diagonal lines in FIG. 4, the scramble-related information bits are multiplexed into the control signal, range bit, and independent data area.

[0021] Furthermore, these multiplexed scramble-related information bits are diagonally multiplexed from the multiplexed position into a fixed position in the audio frame for each audio mode and an independent data area whose area changes depending on the audio mode. It is classified as something that does. Scrambling related information bits present in the control code area and range bits are present at fixed positions for each audio mode. The respective bits and positions are shown below. Video scramble flag bit...12th bit of control code, scramble timing bit...13th bit of control code, audio scramble flag bit...
・r#8 bit position. On the other hand, FIG. 5 shows how scramble-related information is multiplexed diagonally in an independent data area whose area changes depending on the audio mode. (Figure 5) is
FIG. 3 is a diagram of a diagonal multiplexing method showing how 288 bits of scrambling related information bits are multiplexed between 18 audio frames in A1 mode. As shown in Fig. 5, the scrambling related information is diagonally multiplexed one bit for each line in the audio frame, and 18 audio frames, or 288 bits, are taken as one unit (hereinafter, these 18 audio frames are defined as a super frame). There is.

[0022] The descrambling unit 6 extracts and decodes these scramble-related information bits from the DBS 13, and as for the video signal, the scramble digital MUSE
The signal 19 is descrambled and a digital descrambled video signal 12 is output. As for the audio signal, a PN signal 11 is generated so that it can be descrambled by the exclusive OR element 7 at the subsequent stage. The audio processing unit 5 uses digital MUS
Extract the audio data during the blanking period from the E signal,
For descrambling, the audio signal format is returned to the scrambled position on the broadcasting station side, that is, the state where PN addition is performed on the audio signal. Since the audio signal is scrambled just before bit interleaving, the receiving side returns the audio signal format to the audio frame format in this state, and adds the same PN signal 11 that was added during scrambling to the DBS 13 as an exclusive logic The audio signal is descrambled by addition by the summation element 7.

Next, the descrambled DBS 15 is input to the scramble related information bit erasing section 43. The related information bit erasing section 43 erases all the scramble related information in the data bit stream after descrambling. This is because if scramble-related information remains in the descrambled MUSE signal, the subsequent MUS
This is because the E-decoder recognizes the MUSE signal as a scrambled MUSE signal even though it has been descrambled, so the program cannot be viewed normally.

(FIG. 2) shows an example of the circuit configuration of the scramble-related information erasing section. In (Figure 2), 15 is DB
At S, the output of the exclusive OR element 7 is input. 6
2 is an audio frame synchronization signal (FSY), and 63 is an audio reference clock of 1.35 MHz (ACK). 60 is an audio bit counter, which is reset for each audio frame.
CK63 counts from 0 to 1349. 69 is a bit gate, and among the scramble related information bits,
It indicates the timing of related information bits that exist at fixed positions in the audio frame depending on the audio mode, such as the control code bit and the R#8 bit. 64 is a data flip-flop, and the first bit of a control code indicating the audio A/B mode (hereinafter, the first bit to the 22nd bit of the control code are b#1 to b, respectively).
#22) is detected.

Reference numeral 68 denotes a diagonal multiplexing timing generation circuit which detects the audio mode for determining the diagonal multiplexing position in the audio frame of scramble-related information and outputs a pulse indicating the start timing of each row of the audio frame. 90 is DBS1
5 is a pulse for detecting b#1, 91 is a timing pulse for detecting b#1 to b#6 indicating the audio mode,
92 is a timing pulse for detecting b#14 indicating the audio master frame timing which is transmitted every 2 super frames, that is, every 36 audio frames, and 93 is a pulse signal indicating the beginning of each line in the audio frame.

70 is a data flip-flop which converts the timing pulses 91 of b#1 to b#6 indicating the audio mode to 1/
Delay by 2 clocks. 71 is an AND device, which is a burst timing clock for detecting b#1 to b#6 indicating the audio mode of the data bit stream 15 by gating the audio reference clock ACK by the output of the data flip-flop 70; to occur. 72
is a data flip-flop, and a burst clock from 71 causes b#1 to b#6 of the data bit stream.
Detect. 73 is a shift register, and 74 is a data flip-flop, which outputs the output of the data flip-flop 72, that is, b#1 to b#6 in parallel. A data flip-flop 75 detects b#14 in the DBS 15 using a b#14 detection timing pulse 92 for each voice frame in order to detect the voice master frame timing. 76 is a data flip-flop,
Reference numeral 78 denotes an AND element, and this combination differentiates the b#14 detection signal output from the data flip-flop 75 into one clock width. Reference numeral 79 denotes an audio frame row counter, which is a 288-decimal counter that is reset every master frame, that is, every 36 audio frames, and counts and outputs audio data row positions 0 to 287 within the super frame. 94 is a delay adjustment circuit, which adjusts the line pulse 9 by the output of the AND element 78.
The timing is adjusted so that the voice frame row counter 79, which uses 3 as a counter clock, is appropriately reset.

80 is a bit position counter in the audio frame line, which is reset every line pulse 93 and is set from 0 to 81.
Count and output. A ROM 81 outputs the diagonally multiplexed bit position in each row of scramble-related information bits from each audio mode output value of the data flip-flop 74 and the output value of the audio frame row counter 79. A comparator 82 generates a pulse when the output of the bit position counter 80 and the output of the ROM 81 are equal. Reference numeral 96 is a data bit stream delay adjustment circuit that adjusts the timing with respect to the output of the bit gate 69 and the output of the comparator 82. 95 is a delay adjustment circuit for timing adjustment between the output of the bit gate 69 and the data bit stream. Reference numeral 65 denotes an AND element, which erases the scramble-related information bits at fixed positions in the audio data bit stream by forcibly turning them LOW based on the output of the timing adjustment delay circuit 95. 67
is an AND element, which erases the diagonally multiplexed bits of the scramble-related information bits in the audio data bitstream by forcing them to LOW based on the output of the comparator 82.

The operation of the scramble-related information bit erasing section will be explained below with reference to FIG. 2 and FIG. 3. (FIG. 3) is a signal waveform diagram showing signal waveforms of each part of the scramble-related information erasing section shown in (FIG. 2). (Figure 3)
The numbers 1 to 1350 shown in the waveform of medium DBS15 are D
It shows the transmission order of each bit in the voice frame in the BS state. FSY62 is an audio frame synchronization signal indicating the timing of the first bit of the audio frame as shown in the figure.

First, there are fixed positions for each audio mode.
Video scramble flag bit...12th bit of control code, scramble timing bit...13th bit of control code, audio scramble flag bit...r#
The operation of erasing the scramble-related information bits at the 8-bit position will be explained. b#1 90 outputs a pulse at the timing of detecting b#1 as shown in FIG.
The mode is connected to bit gate 69 as shown (FIG. 2). As a result, the bit gate 69 is located at a fixed position for each audio mode. Video scrambling flag bit...12th control code bit, scrambling timing bit...13th control code bit, audio scrambling flag bit... Outputs a pulse signal indicating r#8 bit position. This pulse signal is delayed and adjusted and is the output of the delay adjustment circuit 95 (FIG. 3), which is used as a gate signal to control the delayed DBS at the timing shown in FIG.
By forcing the relevant bits of 96 to LOW, the scramble related information bits at fixed positions are erased for each audio mode.

Next, regarding the erasing operation of the scramble related information bits that are diagonally multiplexed in the independent data area whose area changes depending on the audio mode, similarly (FIG. 2) and (FIG. 3)
Explain using. Scrambling related information bits that are diagonally multiplexed are superframes (18 audio frames)
It is composed of one unit. These 18 audio frame units are detected on the receiving side based on the master frame first frame identification bit b#14 sent every 36 audio frames. Data flip-flop 75 shown in (Figure 3)
The output signal is b#1 of the diagonal multiplex timing generation circuit 68.
4 timing output 92 allows b# in the DBS15 signal
14 is shown.

In the example shown in FIG. 3, b# of this audio frame is
14 is active, ie, the first audio frame of the master frame. This signal is connected to a data flip-flop 76, an AND element 78, and a delay element 94 as shown in (Fig. 2), and is differentiated so that the line counter 79 is reset at the timing of the line pulse 93 shown in (Fig. 3). , delay adjusted. The output of the line counter 79 reset in this way is, as shown in FIG. 3, for one super frame (18 audio frames).
Count up the line pulse 93 from 0 to 287.

Further, the in-line bit counter 80 (FIG. 3)
) is reset by a line pulse 93, and the bit positions 0 to 81 in the row of each audio frame are counted and output.

On the other hand, the data flip-flop 74 outputs b#1 to b#6 indicating various audio modes to the ROM 81 at every timing of b#14 as shown in FIG. 3. The ROM 81 determines the independent data area in the audio frame from the audio mode indicated by b#1 to b#6, and further uses the output of the line counter 79 to determine the scrambling related information for the corresponding diagonal multiplexing in the independent data area. The bit multiplexing position is output for each row as shown in the output of the ROM 81 (FIG. 3). The comparator 82 uses this ROM 81
The output of the in-line counter 80 is compared with the output of the in-line counter 80, and when they match, a pulse signal is generated as shown in the output of the comparator 82 (FIG. 3).

Using the output signal of the comparator 82 as a gate signal, the AND element 67 forces the diagonally multiplexed bits of the data bit stream to LOW, thereby erasing the diagonally multiplexed scramble related information bits. As described above, all scrambling related information bits in the DBS are erased and input to the bit interleaving unit 41 (FIG. 1).

[0035] The subsequent processing will be explained below (see Fig. 1).
). Bit interleaving section 41, B
CH (82, 74) processing device 42, 25 frame interleave device 44, 2/3 value conversion device 46, 12.15
-> The 16.2MHz conversion filter section 47 is a MUSE audio encoding processing section that re-encodes the MUSE audio processing decoded by the audio processing section 5, but this is similar to the corresponding section of a normal MUSE audio encoding processing section. Therefore, the explanation is omitted here. The encoded audio signal delay circuit 48 adjusts the delay of the encoded audio signal and adjusts it to the vertical blanking period of the video signal, thereby reducing the signal processing time required from descrambling the audio signal to re-encoding and the video output in the descrambling unit 6. Signal descrambling Absorbs the difference in signal processing time. Here, the main signal processing time required for re-encoding the audio signal is approximately 1 msec for the bit interleaving unit 41.
．． , 25 audio frame interleaving section 44 is approximately 25 m long.
sec. , the time axis compressor 45 compresses approximately 16 msec. Therefore, it takes about 40 msec. It takes. On the other hand, the signal processing time required to descramble the video signal is up to 130 seconds.
Since it is a horizontal scanning line segment, it takes approximately 4 msec. It is. This means that in order to re-multiplex the re-encoded audio signal at the position of the original audio signal during the vertical blanking period of the video signal, it takes about 30 msec. This indicates that a video signal delay circuit is required. In addition, since the digital video signal has a reference clock of 16.2 MHz and a 10-bit quantization symbol, 3
0 few msec. The memory capacity of the video signal delay circuit is 7 to 8 Mbit. However, here, by taking advantage of the fact that visual characteristics are relatively insensitive to the delay of audio with respect to video, the re-encoded audio signal is delayed and re-multiplexed during the vertical blanking period of the video signal. It eliminates the need for a video signal delay circuit that requires 7 to 8 Mbit of memory, and allows for a maximum of 22.5 Kbit (audio signal data multiplexed in one vertical blanking period is 22,500
This was realized using an audio signal delay circuit that can be configured with a memory with a capacity (consisting of bits). Next, the changeover switch 50
In the audio multiplexing period, the output signal is switched from the output of the audio/video delay circuit 48 to the audio signal side according to the output signal of the audio timing control section 49.

As described above, according to this embodiment, the scrambled digital MUSE signal and the audio data bitstream after 25 frame deinterleaving and BCH (82, 74) error correction are input, and the audio data bitstream is decoded. A digital M that performs descrambling processing on the video signal portion of the pseudo-random signal (PN signal) for scrambling and the scrambled digital MUSE signal.
a descrambling unit device that outputs a USE signal;
an exclusive OR device that adds the PN signal output from the descrambling unit device and the scrambled audio data bitstream and descrambles and outputs the audio data bitstream, and receives the descrambled audio data bitstream as input; A scramble-related information bit erasing device that erases multiplexed scramble-related information bits, and re-MU of the audio data bitstream from which the scramble-related information bits have been erased.
Bit interleaving device, BCH (82,74) error correction addition device, 25 frame interleaving device, time axis compression device, binary/3 for SE audio encoding
Re-audio MUSE consisting of a value conversion device, 12.15MHz/16.2MHz resampling waveform shaping filter device
an encoding device, a delay device for delaying the audio signal output from the re-audio MUSE encoding device, and multiplexing the re-audio MUSE encoded signal output from the delay device at the audio data signal position of the output of the descrambling unit device. By providing a signal switching device for controlling the signal switching device and a timing control device for controlling the signal switching device, after the audio signal portion of the scrambled MUSE signal is descrambled, the multiplexed scramble related information bits are erased and the MUSE audio encoding process is performed again. Thereafter, by re-multiplexing the video signal section with the descrambled MUSE signal, it is possible to output a signal in the normal MUSE signal format in which the scrambled MUSE signal has been descrambled.

[0037]

As described above, according to the present invention, a scrambled digital MUSE signal and an audio data bitstream after 25 frame deinterleaving and BCH (82, 74) error correction are input, and the audio data bitstream is A digital M that has undergone descrambling processing on the video signal portion of the pseudo-random signal (PN signal) for descrambling and the scrambled digital MUSE signal.
a descrambling unit device that outputs a USE signal;
an exclusive OR device that adds the PN signal output from the descrambling unit device and the scrambled audio data bitstream and descrambles and outputs the audio data bitstream, and receives the descrambled audio data bitstream as input; A scramble-related information bit erasing device that erases multiplexed scramble-related information bits, and re-MU of the audio data bitstream from which the scramble-related information bits have been erased.
Bit interleaving device for SE audio encoding, BCH (82,74) error correction addition device, time axis compression device, binary/ternary conversion device, 12.15MHz/16
．． A re-audio MUSE encoding device comprising a 2MHz resampling waveform shaping filter device, and the re-audio MUSE
A delay device that delays the audio signal output from the E encoding device, a signal switching device that multiplexes the output of the encoded audio signal delay device on the audio data signal position of the output of the descrambling unit, and a signal switching device that controls the signal switching device. By providing a timing control device that can descramble the scrambled MUSE signal with a simple configuration and output it in the regular MUSE signal format, the MUSE pay broadcast decoder of the present invention can be connected to various MUSE devices such as MUSE VTR at the subsequent stage. Connection is possible, and in that case, the audio signal portion is descrambled and then re-multiplexed into the MUSE signal in digital signal format, so it has the effect of not causing any deterioration in sound quality.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a pay broadcast decoder in an embodiment of the present invention.

[Fig. 2] Block diagram showing the configuration of main parts of the present invention

[Figure 3]
Timing diagram to explain the operation of the main parts

[Fig. 4] Frame configuration diagram of MUSE audio signal showing the multiplexing position of scramble-related information

[Fig. 5] Scramble-related information multiplexing method diagram showing a diagonal multiplexing method of scramble-related signals to independent data areas

[Fig. 6] Block diagram showing the configuration of a conventional MUSE pay broadcast decoder

[Explanation of symbols]

6 Descrambling unit device 7 Exclusive OR device 43 Scramble related information bit erasing device 41
Bit interleaving device 42 BCH (82, 74) error correction code adding device 4
4 25 frame interleaving device 45 Time axis compression device 46 Binary/Three value converting device 47 12.15/16.2 MHz resampling waveform shaping filter device 48 Delay device 50 Signal switching device 49 Timing control device

Claims (1)

[Claims] Claim 1: A pseudo-random system for descrambling an audio data bitstream, which inputs a scrambled digital multiplexed sampling coded signal and an audio data bitstream after 25-frame deinterleaving and BCH (82, 74) error correction. A descrambling unit device that outputs a digital multiplex sampling coded signal that has undergone descrambling processing on a video signal portion of the digital multiplex sampling coded signal, and a pseudorandom signal output from the descrambling unit device and a scrambled digital multiplex sampling coded signal. an exclusive OR device that adds the descrambled audio data bitstreams and outputs the audio data bitstream; and a scramble-related information bit eraser that receives the descrambled audio data bitstream and erases the multiplexed scramble-related information bits. a bit interleaving device, a BCH (82, 74) error correction addition device, a 25 frame interleaving device, and a timer for re-multiplexing the audio data bitstream from which scramble-related information bits have been removed into a multiplexed sampling coded signal; axial compression device,
Binary/three-value conversion device, 12.15MHz/16.2MH
an audio re-multiplex encoding device for converting a multiple sampling encoded signal to a z-resampling waveform shaping filter device;
a delay device for delaying the audio signal output from the audio re-multiplexing encoding device into the multiplex sampling encoded signal; The audio remultiplexing device is configured to include a signal switching device for multiplexing encoded audio signals, and a timing control device for controlling the signal switching device;
After descrambling the audio signal of the scrambled multiple sampling encoded signal, the multiplexed scramble-related information bits are erased, and the audio signal after the audio re-multiplex encoding process is converted into the multiple sampling encoded signal by a descrambling unit. The scrambled multiple sampling encoded signal is descrambled by adjusting the delay to the timing of the audio signal region of the descrambled video signal output from the device and re-multiplexing the video signal part to the descrambled multiple sampling encoded signal. A pay broadcast decoder is characterized in that it performs the following and outputs it in a regular multiple sampling encoded signal format.