JPS59117837A - Synchronism system of television sound signal - Google Patents

Abstract

PURPOSE:To simplify a constitution without requiring complicated processing by synchronizing a transmission and receiving system by an ID signal inserted with the prescribed period of a television signal and the synchronizing signal of a video signal. CONSTITUTION:A vertical synchronizing signal VD and a horizontal synchronizing signal HD in a composite video signal are detected by a synchronous separating circuit 2, applied to an ID generator 3 to form the ID signal. That is, a counter 3a applies the 13H-th counted value to an adder 4 as the ID signal, which is inserted in the video signal at an input terminal 1 and outputted to a decoder side via an output terminal 5. The signals HD and VD are separated from the composite video signal at a synchronous separating circuit 12 at the decoder side, the signal HD is applied to an ID detector 13, the 13H-th of the vertical blanking period is checked to detect the ID signal. This ID signal is outputted to an output terminal 16 as a block signal at a gate circuit 15 and a sound signal scrambled based on this signal and a segment synchronizing signal is descrambled to obtain the original sound signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a synchronization method for television audio signals, in particular, to scramble audio signals and transmit them.
The present invention relates to a television audio signal synchronization method suitable for use in a confidential communication method, etc., in which the original audio signal is obtained by descrambling it in step 411.

Background Art and Problems Generally, in pay television broadcasting systems, a broadcasting station (sender) and a user (receiver) enter into a contract under which a fee is paid in exchange for enjoying a specific television broadcast. In wireless communication, as a general rule, it is not possible to restrict the number of recipients, so a confidential system for audio signals is used so that only users who have signed such a contract can enjoy television broadcasting. These confidential communication methods for television audio signals mainly include methods such as rearranging the audio signals on the time axis or on the frequency axis, but in either method, the transmission In order to descramble a previously scrambled audio signal, it is necessary to synchronize both the scrambler and descrambler sides. Conventionally, a method of superimposing a synchronization signal within the audio signal band has been used to achieve synchronization between the two, but in this method,
There were disadvantages such as the transmission signal band was sacrificed, or complicated processing was required to detect the synchronization signal, and the configuration for that purpose was also complicated.

Purpose of the Invention In view of the above, the present invention provides a television in which transmission and reception systems can be easily synchronized by using vertical synchronization signals, horizontal synchronization signals, etc., which are synchronization signals of television video signals, as synchronization signals. This provides a synchronization method for John Audio No. 18.

Summary of the Invention In this invention, an ID signal is inserted into a predetermined section of a television signal, for example, in a vertical retrace interval, and the transmission and reception system is synchronized by this ID signal and a synchronization signal of a television video signal. With a simple configuration, it is possible to easily synchronize the transmission and reception systems, for example, between the scramble side and the descramble side in a confidential communication system.

Embodiment Hereinafter, a case in which the present invention is applied to a secret speech system in which single-voice signals are rearranged on the time axis will be explained in detail based on FIGS. 1 to 3.

First, the basic principle of this invention will be explained with reference to the signal waveforms shown in FIG. In the same figure, FIG. 1 shows the distribution of the video signal 8V of the television signal and the vertical synchronization signal VD,
Figure 1B shows the audio data arrangement, and Figure 1C shows an enlarged vertical retrace section of the video signal in Figure 1.In Figure 1C, the first 3H is equalized. The next 3H pulse is a vertical synchronization pulse, and the last 3H is an equalization pulse. Further, the first diagram shows audio data corresponding to FIG. 1C.

For example, consider a case where an audio signal is divided into a plurality of blocks on the time axis, each block is composed of four segments, and the order of the segments is rearranged in each block. Now, suppose that the length of one segment is an integral multiple of the vertical scanning interval (V) of the video signal, for example, four times,
In other words, l) l segment is 66.7 fF 1 second, and 1 block is 267 msec.

Then, in the video signal, for example, the rising edge of the 5th H of the vertical retrace interval shown in FIG. As shown in the figure, the switching point S of the audio signal segment
1, and the subsequent <4Vth tie point is defined as one segment (see FIG. 1B). On the other hand, the ID signal is transmitted at a predetermined position in the 3V-th vertical retrace interval from the switching point of the first segment of each block, for example, the switching point S1 shown in Fig. 1, for example, at the 13H, as shown in Fig. 1A. As a result, the rising edge of the 5th H of the next V becomes the switching point 8 of the material signal block as shown in FIG. 1B.
Switching point S2 represents a segment switching point when no ID signal is inserted before the IV, while it is both a segment switching point and a block switching point when an IiH signal is inserted.

If this ID signal is a continuous audio signal, it is only necessary to insert it once at the beginning of the transmission, and then synchronization can be achieved by simply counting the vertical scanning interval (2). However, if synchronization occurs due to noise in the signal transmission system or discontinuity in the television signal, this can be done by inserting this ID signal periodically or randomly as necessary. It is also possible to prevent synchronization.

FIGS. 2 and 3 each show an example of the configuration of an encoder and a decoder used in the synchronization method according to the present invention.

First, in Fig. 2 showing the configuration of the encoder, when a composite video signal including a synchronization signal is supplied from an input terminal (1) to a synchronization separation circuit (phantom), the vertical synchronization signal included in this composite video No. 11 is VD and horizontal synchronization signal) ID are detected respectively. These synchronization signals are then used by the ID generator (
3), where an ID signal is formed. That is, the horizontal synchronization signal HD from the synchronization separation circuit (2) is supplied to the 13H counter (3a) in the ID detector (3), and the horizontal scanning section H is counted by 13 for each ■. , On the other hand, the vertical synchronization signal VD is sequentially supplied from the synchronization separation circuit (2) to the 16V counter (3b), and the vertical scanning section (2) is counted 16 times at a time. And the counter (3b) is 16V; 1 count (1 count of audio signal)
(corresponding to the block length), the counter (3a) uses the 13th H count value of (2) as an ID signal and sends it to the adder (
4), where the ID signal is inserted into the video signal from the input terminal (1) in the above-mentioned relationship. That is, in this case, the ID signal is inserted at the 13th H of the vertical retrace interval of the video signal corresponding to the third switching point of the first segment of each block of the audio signal. And this ID
The video signal into which the signal has been inserted is transmitted to the decoder side via the adder (fourth output terminal (5)).

On the other hand, one block of Ondo A is composed of four segments, that is, 16V, so every time Karan 5I (3b) counts 16V, for example, 1■ delay circuit (3C
) A block synchronization signal is taken out to the output terminal (6). Note that the delay circuit (3c) is used here to delay the block synchronization signal by 1■ when the video signal and audio signal are out of sync, such as when adjusting the tracking volume at V'l on the decoder side. ID in video signal
The signal will also deviate from the audio signal by that amount, so in order to compensate for this deviation, the encoder side delays the audio signal block 1) J signal by about IV with respect to the ID signal. On the sending and decoder side, the ID signal is delayed by the amount of the above-described adjustment to eliminate the deviation from the block synchronization signal. In addition, the vertical synchronization signal from the synchronization separation circuit (2) is connected to a 4V counter (7).
is supplied to 4V and counted in 4V increments, and a delay circuit (3C
) is supplied to the output side of the counter (7), and a block synchronization signal, that is, a 4V signal synchronized with the ID signal, is obtained at the output side of the counter (7), and this signal is applied to each block of the audio signal. It is sent to the output terminal (8) as a synchronization signal for each segment within the segment.

Then, the audio signal is scrambled using block and segment synchronization signals obtained at these output terminals (6) and (8), respectively, and the scrambled audio signal is sent to the decoder side via the transmission system.

Figure 3 shows an example of the circuit configuration on the decoder side. In the figure, the input terminal Qυ is supplied with a composite video signal including an ID signal from the output terminal (5) on the encoder side. The composite video signal is supplied to the synchronization separation circuit (6), thereby separating the horizontal synchronization signal HD and the vertical synchronization signal VD, of which the horizontal synchronization signal HD is sent to the ID detector (toward).
supplied to This ID detection detector α checks the 13th H of each vertical blanking interval of the video signal and detects the ID signal inserted on the encoder side into the video signal supplied from the input terminal αp. When the ID signal is detected, this I
The D signal is supplied to the gate circuit α0 via the delay circuit (141).

After being supplied with the ID signal, the gate circuit Moe opens its gate in synchronization with the rising edge of the 5th H of the next vertical blanking interval, and sends its output signal to the output terminal αQ as a block synchronization signal. Note that the delay circuit α→ is connected to the above-mentioned video signal (within ID
This is to adjust the deviation between the video signal and the audio signal.The decoder side adjusts the tracking volume of the VTR, etc. (not shown), and as a result, the video signal and the audio signal are adjusted, and as a result, the audio signal ) The ID signal is delayed by the delay circuit a→ by the amount of signal deviation, so that the ID signal and the block synchronization signal of the audio signal match.

On the other hand, the vertical synchronization signal VD from the synchronization separation circuit 04 is supplied to a 4V counter 0'j) to count in increments of 4■, and the obtained block synchronization signal is supplied to the output side of the gate circuit (to). Vertical synchronization signal VD at α power
Based on this, a 4■ signal synchronized with the ID signal is generated. Since one segment of the audio signal corresponds to 4■, these 4
The signal of v is sent to the output terminal (g) as a segment synchronization signal.

Therefore, based on the block synchronization signal and segment synchronization No. 1 obtained at these output terminals (2) and (to),
To descramble a scrambled audio signal transmitted from an encoder side. As a result, the original descrambled audio signal is obtained on the decoder side.

In the above embodiment, one segment of the audio signal is set to 4V,
Although the explanation has been made taking the case where one block is 16V as an example, the length of these segments and the length of the block are not limited to these, and can be set to any length.

For example, it is also possible to set the length of one segment to a length that is not an integral multiple of the vertical scanning interval (2), such as 4.3 (4.3) or 7.2 (2). In this case, it is possible to create the required length by not only counting the vertical scanning section (3) but also counting the horizontal scanning section H. Also, how many types of ID signals can be prepared, and the length of blocks and segments can be changed, the sorting method can be changed, or the ID signal can be used not only at the beginning of a block but also at the beginning of the nth segment. It is also possible to apply this method to realize a more complicated scrambling method, such as by using a synchronization signal as shown in FIG.

Effects of the Invention As described above, according to the present invention, an ID signal is inserted in a predetermined interval such as a vertical retrace interval of a television video signal, and a synchronization signal between the ID signal and the television video signal is used to control the transmitting/receiving system. By synchronizing, it is possible to easily synchronize the transmitting and receiving systems, such as the scrambling side and the descrambling side in a confidential communication system, using the synchronizing signal of the television video signal. There is no need to sacrifice the transmission signal band or perform complicated processing to detect the synchronization signal as in the conventional case, and thus the transmission signal band can be used effectively and the configuration can be simplified.

[Brief explanation of the drawing]

Fig. 1 is a signal waveform diagram for explaining the basic principle of this invention, Fig. 2 is a system diagram showing an example of the encoder side of an embodiment of this invention, and Fig. 3 is a diagram of an embodiment of this invention. FIG. 2 is a system diagram showing an example of a decoder side. (2), θ2) is a synchronous separation circuit, (3) is an ID generator,
(4) is an adder, (7) * (L force is 4 ■ counter,
α[Yes] is an ID detector, Q→ is a delay circuit, and αe is a gate circuit. Procedural amendment dated April 15, 1980 1. Indication of case Patent application No. 232259 of 1988 2. Title of invention Synchronization method for television audio signals 3
, Relationship with the case of the person making the amendment Patent Applicant Address No. 6-7-35, Kitashinyo, Tokyo Parts Store Name (21
8) Norio Ohga, representative director of Sony Corporation, 5, date of amendment order: 6, 1939,
Number of inventions increased by amendment 8, content of amendment (1) In the specification, "detector" in line 4 on page 6 is changed to "generator"
I am corrected. (2) Same, page 11, line 9 [Scramble'fl! I
Correct K j to "scramble side". (3) In the drawings, Figure 1 will be corrected as shown in the attached sheet. that's all

Claims (1)

[Claims] An ID signal is inserted into a predetermined period of a television signal, and the
A television audio signal synchronization system characterized in that a transmitting and receiving system is synchronized by a synchronization signal of a D signal and a television video signal.