JPS6376594A - signal processing device - Google Patents

Abstract

PURPOSE:To transmit and reproduce a digital sound signal having a high definition while maintaining the compatibility with the transmission/reception system for the television signal of such as NTSC system by providing a modulator to digitize a sound signal, time base compressor, and a switch means to a transmitter, and providing a time base demodulator and a D/A demodulator to a receiver. CONSTITUTION:An adaptible delta modulation ADM modulator 6 modulates a high-definition sound signal into a one bit digital signal, and input it to the time base compressor 8 through a delayer 7. The time base compressor 8 compresses the time base of the one bit digital sound signal, and the result is inputted to a bit converter 11, where the digital sound signal of two bits that are the high order bit and the low order bit is converted to an eight bit signal and inputted to a switch 10. In the receiver, the eight bit FUCE signal is inputted to a bit converter 16 where the signal is converted to a two bit signal, and the result is inputted to the time base demodulator 17. A one bit digital sound signal whose time base is demodulated is inputted to the ADM modulator 19. The modulator 19 modulate the signal to the high-definition sound signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a television signal processing system, and more particularly to an audio signal multiplex demodulation device for realizing high quality audio.

[Conventional technology]

Publicly known example ``Results of compatibility test of existing receivers with pulse signal superimposed on horizontal blanking period and modified horizontal synchronization signal'' by Akira Otani, at the 1981 IEICE General Conference, conventional television receivers ( We are currently investigating how much digital data can be multiplexed during the horizontal retrace period while maintaining compatibility with the NTSC system. According to this study, it is possible to transmit digital data at 12 pits (12b/H) per horizontal retrace period, or in other words, about 190 Kbps (190 kilopits/second). (190K
b/Sζ12b/HX 525HX 30Hz) On the other hand, to transmit high quality digital audio, approximately I DJbps
transmission capacity is said to be required. (IMb/5
A=32 KHz x 16b x 2ch) [Problems to be Solved by the Invention] In the above-mentioned conventional technology, expansion of the achievable transmission capacity and reduction of the required transmission capacity have not been sufficiently studied. Therefore, it has been considered difficult to multiplex high-quality digital audio signals while maintaining compatibility with conventional televisions.

The object of the present invention is to provide signal processing that can transmit and reproduce high-quality digital audio signals while maintaining compatibility with television signal transmission and reception systems such as the NTSC system.

The goal is to provide equipment.

[Means for solving problems]

The above object is achieved by using the following means. The first method is to use ADM (adaptive delta modulation) instead of PCM (pulse code modulation) as the audio signal modulation method. The second method is to transmit the digital audio signal not in binary (1 bit) per sample but in multi-value, for example, 4-value (2 bit). The third method is to extend the period in which digital audio signals are multiplexed not only to the front porch and back porch of the horizontal scanning period but also to the scanning period which cannot be seen on the screen due to overscanning. The fourth means increases the instantaneous bit rate to 5.73 Mbp
s to 7.16 Mbps.

[Effect]

By employing ADM, which is the first means, it is possible to reduce the necessary transmission capacity by half without reducing sound quality. According to Dolby Laboratories, the sound quality of 251.7 Kbps/ch has a bandwidth of 17 KHz and a dynamic range of 90 dB, which is equivalent to or better than the sound quality of PCM of about 450 Kbps/ch. (References Niss MBI Journal October 1985 1 MB TEJ Journal
nal November 1985 [B-MAC
: Transmission Standard for
r Pay DB S J) The second method, multilevel transmission, increases the number of pits/samples, so the transmission capacity can be increased. The transmission capacity can be increased by extending the digital audio signal multiplexing period to the scanning period, which is the third means. At this time, since the scanning period in which digital audio signals are multiplexed is set to a portion that does not appear on the screen due to overscanning, compatibility with conventional televisions can be maintained.

The fourth method, changing the bit rate from 5.73 Mbps to 7.16 Mbps, increases the transmission capacity by 1.
It can be multiplied by 25 times.

For example, ADM, 4-level transmission, bit rate 7.16
Consider a case where Mbps f is adopted and the multiplexing period is extended by one sample to the horizontal scanning period immediately before the front porch compared to the known example. The achievable transmission capacity and the required transmission capacity are as follows.

Realizable transmission capacity = (12X-+1)X2X52
5X305.13 = 504Kbps Required transmission capacity = 251.7 x 2 = 503.
4 Kbps As is clear from this example, the combination of these four means makes it possible to multiplex digital audio signals that are compatible with televisions having an NTSC scanning line structure.

〔Example〕

FIG. 1 shows one embodiment of the present invention.

Figure 1(a) shows an F with a digital audio signal multiplexing device.
The figure (b) shows a UCE type television signal transmitter and a FUCE type television signal receiver having a digital audio signal demodulator. First, we will show the overall operation and configuration. Video signals R-G-B, horizontal/vertical synchronizing signals HD/VD, conventional audio signals, single character multiplex signals, etc. are input to the FUCE encoder 2 through the input terminal group 1. Here F U
CE (Full Compa-tible Enco
ding) is a high-definition T that is fully compatible with NTSC.
It is a V method. [References: Television Society Journal Vol.1
．． 39, Nn1O (1985) 885-897]
The high quality audio signals of the R (right) and L (left) channels are
The signals are input to the matrix 5 through input terminals 3 and 4. Matrix 5 connects R+L and R-L.
Input to M modulator 6. The ADM modulator 6 modulates the high quality audio signal into a 1-pit digital signal and inputs it to the delay device 7. The delay unit 7 inputs a 1-bit demo signal so that the timing of the video signal and the high-quality audio signal match at the output of the receiver. The timing generator 9 determines the frequency and phase for multiplexing the digital audio signal and the gate pulse GP that defines the period for multiplexing the digital audio signal, based on the HD, VD, and color subcarrier pulses SC obtained from the FUCE encoder 2. A specified clock pulse CPk, a clock pulse GP, and a clock pulse CP are inputted to a time axis compressor 8 and a 4-gate pulse GPY switch 10. The time axis compressor 8 compresses the time axis based on the 1-bit demo pulse GP and the clock pulse CP, and inputs them to the bit converter 11.

The bit converter 11 converts a 2-pit digital audio signal with the R+L 1-bit demo audio signal as the upper bit and the R-L 1-pit digital audio signal as the lower bit into 8 bits, and inputs it to the switch 10. . F.U.C.
The E encoder 2 creates an 8-bit video signal and inputs it to the switch 10. The switch 10 selects and outputs a video signal and a digital audio signal based on the gate pulse GP, multiplexes them on the time axis, and sends them to F.
Input to UCE encoder 2. FUCE encoder 2
is an analog FUC on which digital audio signals are multiplexed.
The E signal is output from the output terminal 12. In the receiver, the FUCE signal, which is a multiplexed digital audio signal, is sent to input terminal 1.
3 to the FUCE decoder 14. F.U.C.
The E decoder 14 demodulates video signals R/G-B, horizontal/vertical synchronizing signals HD/VD, conventional audio signals such as two-character multiplex signals, and outputs the demodulated signals from an output terminal group 15. At the same time, a digital audio signal is multiplexed. The 8-bit FUCE signal is input to the bit converter 16. The bit converter 16 converts the 8-bit input signal into 2-bit signals and inputs them to the time domain demodulator 17. The timing generator 18 generates a gate pulse GP that defines the period for demodulating the digital audio signal and a clock pulse CP that defines the frequency and phase for demodulating the digital audio signal based on the HD, VD, and SC supplied from the FUCE decoder 14. and input them to the time domain demodulator 17. The time axis demodulator 17 demodulates the time axis of the 1-bit digital signal based on the gate pulse GP and the clock pulse CP.
Bit demo demodulator 19 demodulates to a 1-bit demo audio signal and inputs it to matrix 20. The matrix 20 returns the high quality audio signals of R+L and RL to the high quality audio signals of R and L and outputs terminals 21 and 22.
Output from.

The d matrices 5 and 20, which will now be described with reference to the operation and configuration of each block, are configured by, for example, differential amplifiers. The ADM modulator 6 and the ADM demodulator 19 are developed by Dolby Laboratories, for example, and are B-MAC (Multi-MAC).
-rple Analog Components)
204.5KHz sun adopted in.

Bling, control signal 15.7 Kbps, error correction signal 31.5 Kbps, required transmission capacity 125
It is assumed to be a 1.7 Kbps ADM modulator/demodulator. Figure 2 (
An example of a waveform diagram of the gate pulse GP generated by the timing generators 9 and 18 is shown in FIG. 2B. The clock pulse CP is set to 7.16 Ml1lz, which is twice the color subcarrier frequency. The time axis compressor 8 compresses the time axis by writing the digital audio signal into the memory using a clock pulse of, for example, 251.7K)lz, and reading out the digital audio signal using a clock pulse CP. At this time, the memory read period is set by the gate pulse G.
Only when P is at high level. As a result, the digital audio signal is compressed on the time axis as shown in FIG. The converter 16 converts the digital television signal from 8 bits to 2 bits using, for example, the bit conversion table shown in FIG.
A digital signal is written to the memory by the clock pulse CP only when CP is at a high level, for example, 251.7
The time axis is demodulated by reading with a KHz clock pulse.

Next, the effects of this embodiment will be described.

(1) The required transmission capacity is smaller than the achievable transmission capacity (251.7X2Kbps<16X2X52
5 x 30 bps), it becomes possible to multiplex digital audio signals onto FUCE television signals, which was previously impossible.

(2) Since the digital audio signal is transmitted in four values with R+L as the upper bit, the error rate of R+L is R-
It will be lower than that of L. Therefore, even if a television signal passes through a transmission path with poor noise and amplitude distortion characteristics, it can be received with low noise if high-quality audio is reproduced in monaural (R+L only). (3) The digital audio signal has a very simple frequency of 7.16 times twice the color subcarrier frequency.
Transmission at MHz facilitates multiplexing and demodulation of digital audio signals. (4) Since the transmitter side performs a delay to synchronize the timing of high-quality audio and video signals all at once, there is no need to install a delay device on the receiver side, reducing the cost of a large number of receivers. becomes possible.

Further, in the embodiment shown in FIG. 1, the gate pulse OP is 1
A period long enough to multiplex digital audio signals of 16 or more samples per horizontal scan is divided into the front porch during the horizontal blanking period, the horizontal scanning period immediately before the front porch, the back porch during the horizontal blanking period, and the horizontal scanning period immediately after the back porch. If the pulse is defined in a certain period, then Fig. 2(b)
) does not have to be the gate pulse GP shown in FIG. Even in this case, the effects of the embodiment remain the same.

Furthermore, in the embodiment of FIG. 1, matrices 5 and 20
It is also possible to delete and multiplex R and L instead of R+L and RL. In this case, the effects of the embodiment are (1), (3>, and (4)) above.

FIG. 5 shows one embodiment of the present invention. The basic operation and configuration of the embodiment of FIG. 5 is the same as that of FIG. 1. Furthermore, blocks with the same number in FIG. 1 and FIG. 5 are blocks having the same operation and configuration. Here, the embodiment shown in FIG. 5 will be described only with respect to the points that differ from the embodiment shown in FIG. 1. In FIG. 5, 23 and 25 are timing generators, 24 is a time-domain compression block, and 26 is a time-domain demodulation block. Based on the HD, VD, and SC supplied from the FUCE encoder 2, the timing generator 23
A gate pulse GPA that defines a period for multiplexing R+L digital audio signals, a gate pulse GPB that defines a period for multiplexing R-L digital audio signals, and a clock pulse that defines the frequency and phase for multiplexing digital audio signals. Create CP and gate pulse GPA, GP
B and clock pulse CP to the time axis compression block 24,
Gate pulses GPA and GPB are input to the switch 10. The gate pulse GPB is a gate pulse that remains constant only during the horizontal scanning period of a certain number of horizontal scanning lines within the vertical blanking period, and during the horizontal scanning period of a certain number of horizontal scanning lines immediately before and after the vertical blanking period. shall be. Here, for example, only the horizontal scanning period of a total of six horizontal scanning lines, three immediately before the vertical retrace period and three immediately after, are used as the blank level null gate pulse. The gate pulse GPA is the same gate pulse as used in the embodiment shown in FIG. Clock pulse CP is 7.16MHz.

shall be. FIG. 6 shows an example of the configuration of the time domain demodulation block 24. In the figure, 8 and 28 are time axis compressors, and 27 is a series/
29 represents a parallel converter and a switch. The 1-bit digital audio signal RL is converted into 2-bit data by a serial/parallel converter 27 and input to each time-base compressor 28. The time axis compressor 28 writes the digital audio signal into the memory with a clock pulse of 2 KHz.
The time axis is compressed by reading out the digital audio signal using the clock pulse CP. At this time, the memory read period is set only when the gate pulse GPB is at a high level.

The 1-bit digital audio signal R+L is sent to the time axis compressor 8.
The time axis is compressed by The switch 29 outputs an R+L digital audio signal when the gate pulse GPA is at a high level, and outputs an R+L digital audio signal when the gate pulse GPB is at a high level.
- Select and output the L digital audio signal. Therefore, from the transmitter, R+L digital audio signals are multiplexed in binary format during a fixed period of the horizontal retrace period or the horizontal retrace period and the horizontal scanning period immediately before and after it, and the digital audio signal of R+L is multiplexed in binary format during the horizontal retrace period or the horizontal scanning period immediately before and after it. R- with 4 values during the horizontal scanning period of a total of 6 unbalanced scanning lines.
A FUCE signal in which L digital audio signals are multiplexed is output. Similar to the timing generator 23, the timing generator 25 generates gate pulses GPA, GPB, and clock pulse CP, and inputs them to the time axis demodulation block 26. FIG. 7 shows an example of the configuration of the time domain demodulation block 26. In the figure, 17 and 30 are time-domain demodulators, and 31 is a parallel/serial converter.

The time axis demodulator 30 writes a digital signal into the memory using the clock pulse CP only when the gate pulse GPB is at a high level, and writes the digital signal into the memory using the clock pulse CP, for example, at a frequency of 251.7 KHz.
The time axis is demodulated by reading out the digital signal from the memory using the zero pulse. The time axis demodulator 17 demodulates the time axis by writing a digital signal into the memory using a clock pulse CP only when the gate pulse GPA is at a high level, and reading the digital signal from the memory using a clock pulse of, for example, 251.7 KFlz. Parallel/serial converter 30 converts the 2-bit digital audio signal RL to 1 bit. The other processes are the same as those in the embodiment shown in FIG. 1, and a high quality audio signal is reproduced on the receiver side.

Next, the effects of the embodiment shown in FIG. 5 will be described. (1) The required transmission capacity is smaller than the achievable transmission capacity (251
．． 7X2Kbps<16X525X30+371X2X
3 in 6HX60bps52μsec÷0.14μsec
71), which was previously impossible for digital audio signals.
Multiplexing into UCE television signals becomes possible. (2)
R+L is for binary transmission and R-L is for 4-value transmission, so R+
The error rate of L will be lower than that of R-L. Therefore, even if the TV signal is transmitted through a transmission path with poor noise or amplitude distortion characteristics, high-quality audio can be played back in monaural (R+L).
only), you can receive with low noise. (3) Same effect as (3) of the embodiment shown in FIG. (4) Same effect as (4) of the embodiment shown in FIG.

In the embodiment of FIG. 5, it is also possible to delete matrices 5 and 20 and multiplex R and L instead of R,+L and RL. In this case, the effects of the embodiment are the above (1), (3), and (4).

Furthermore, in the embodiment shown in FIG. 5, the gate pulses GPA and GPB are interchanged, and the period for multiplexing R, +L and the period for multiplexing R-
It is also possible to change the period in which L is multiplexed. The effect of the embodiment in this case is (1) above.

(21, (31, (41).

FIG. 8 shows one embodiment of the present invention. The basic operation and configuration of the embodiment shown in FIG. 8 is the same as that of the embodiment shown in FIG. In addition, blocks with the same symbol in FIGS. 5 and 8 are blocks having the same operation and configuration.

Here, only the points different from the embodiment shown in FIG.
The embodiment shown in the figure will be explained. In FIG. 8, 32 represents a time-domain compression block, 33 and 34 represent bit converters, and 35 represents a time-domain demodulation block. The gate pulse GPB generated by the timing generator 23 is applied to a total of 12 horizontal scanning lines, for example, 4 immediately before the vertical retrace period, 4 within the vertical retrace period, and 4 immediately after the vertical retrace period. The gate pulse is set to a high level only during the horizontal scanning period. Gate pulse GP
A and clock pulse CP are the same pulses used in the embodiment of FIG. FIG. 9 shows an example of the configuration of the time axis compression block 32. In the figure, 8 represents a time axis compressor, and 29 represents a switch. The basic operations of the time base compressor 8 and the switch 29 are the same as those in FIG. Bit converter 3
3 converts a 1-bit digital audio signal into 8-bit data according to the bit conversion table shown in FIG. From the transmitter of the embodiment shown in FIG. 8, R+L digital audio signals are multiplexed in binary format during a certain period of time within the horizontal retrace period, and immediately before and after the horizontal retrace period, and during the vertical retrace period and immediately before and after the vertical retrace period. During the horizontal scanning period of a total of 12 horizontal scanning lines, a FUCE signal in which binary R-L digital audio signals are multiplexed is output. The focus converter 34 converts the 8-bit digital signal into 1-bit according to the bit conversion table shown in FIG. FIG. 12 shows an example of the configuration of the time domain demodulation block. In the figure, 17 indicates a time domain demodulator. The basic operation is the same as the time domain demodulation 17 in FIG.

Next, the effects of the embodiment shown in FIG. 8 will be described. (1) The required transmission capacity is smaller than the achievable transmission capacity (251.
7X2Kbps<16X525X30+371X12X
60 bps), it becomes possible to multiplex digital audio signals onto FUCE television signals, which was previously impossible.

(2) Same effect as (3) of the embodiment shown in FIG. (3 [Same as effect (4) of the embodiment in Figure 1).

In the embodiment of FIG. 8, it is also possible to delete matrices 5 and 20 and multiplex up to f of R and L instead of R+L and RL. In this case, the effect of the embodiment is as described in (1) above.
, (21, same as (3)).

Furthermore, in the embodiment shown in FIG. 8, it is also possible to switch the gate pulses GPA and GPB and switch the periods in which R+L and RL are multiplexed. The effects of the embodiment in this case are the same as those in (1), (2+, and (31) above.

The embodiments shown in Figures 1, 5, and 8 are FUCE type TVs.
This is about a transmitter that multiplexes signals and digital audio signals, and a receiver that demodulates them.

On the other hand, a transmitter and a receiver that multiplex and demodulate NTSC TV signals and digital audio signals can also be realized by the present invention. These are Figures 1 and 5.

In the embodiment of FIG. 8, the FUCE encoder 2 and the FU
The CE decoder 14 is converted into an NTSC encoder and an NTSC encoder.
This becomes possible by replacing the C decoder with a C decoder and deleting the delay device 7. NTS in Figures 13, 14, and 15
An embodiment of the present invention will be shown which deals with C-scheme TV signals. In the figure, 36 is an NTSC encoder, and 37 is an NTSC encoder.
A C decoder is shown. The basic operations and effects of the examples are as follows:
The embodiment of FIG. 13 is the same as the embodiment of FIG. 1, the embodiment of FIG. 14, the embodiment of FIG. 5, the embodiment of FIG. 15, and the embodiment of FIG. 8.

〔Effect of the invention〕

According to the present invention, it is possible to realize a television signal transmitter/receiver that can transmit and reproduce high-quality digital audio signals while maintaining compatibility with an NTSC television signal transmitter/receiver system.

According to the present invention, a television signal transmission system that can transmit and reproduce high-quality digital audio signals while maintaining compatibility with a television signal transmission and reception system of a high-definition television system (for example, FUCE system) that is compatible with the NTSC system.・Receiver can be realized.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of an embodiment of the present invention, Fig. 2 is a waveform diagram for explaining the embodiment, Figs. 3 and 4 are pit conversion diagrams of a bit converter, and Fig. 5 is a diagram of a pit conversion of a bit converter. Circuit diagram of the embodiment, No. 6
The figure is a circuit diagram of a time domain compression block, FIG. 7 is a circuit diagram of a time domain demodulation block, and FIG. 8 is a circuit diagram of an embodiment of the present invention.
Figure 9 is a circuit diagram of the time axis compression block, Figure 10 and Figure 1.
1 is a pit conversion diagram of a bit converter, FIG. 12 is a circuit diagram of a time domain demodulation block, and FIGS. 13, 14, and 15 are circuit diagrams of an embodiment of the present invention. 2. FUCE encoder, 5. Matrix, 6. ADM modulator,
7... Delay device, 8... Time axis compressor, 9
...timing generator, 10...switch, 11...bit converter,
14... FUCE decoder, 16... Bit converter, 17... Time axis demodulator, 1
8...Timing generator, 19...ADM demodulator, 20...Matrix,
23...Timing generator, 24...Time axis compression block, 25...Timing generator, 26...Time axis demodulation block, 27...Serial/parallel converter, 28...Time axis compression Device, 29...Switch, 3
0... Time axis demodulator, 31... Parallel/serial converter, 32... Time axis compression block, 33... Bit converter, 34... Bit converter, 35... Time axis Demodulation block, 36...NTSC encoder, 37...NTSC decoder. Beak 5 no i Taku 2nd Kezu Nagi Akira 4 Kuchi Akira S Kuchika Uke j color match /2 A 6 Kuchi Akira 7th circle 56 Kuchi tb + Ukei Ki easy 7th 70th mouth / Noro early 72 concave謬／j 口く／d 口

Claims (1)

[Claims] 1. In a television signal transmitter and receiver, the transmitter includes a modulator that digitizes an audio signal, and a modulator that digitizes the audio signal, and transmits the digitized audio signal for a certain period of the video blanking period and the video scanning period. The receiver is equipped with a time-base compressor that compresses the time-base and a switch that time-division multiplexes the video signal and the time-base compressed digital audio signal. A signal processing device comprising: a time axis demodulator that demodulates the time axis of a digital audio signal; and a demodulator that demodulates the digital audio signal into an analog signal. 2. In claim 1, the modulator is an AD
M modulator, and the time-base compressor is a time-base compressor that compresses the digitized audio signal at a transmission bit rate of 7.16 Mbps during a fixed period of a video blanking period and a video scanning period, and the A signal processing device characterized in that the demodulator is an ADM demodulator.