JPS61189084A - Composite television signal transmission system - Google Patents

Abstract

PURPOSE:To transmit a TV signal while coded bit information is superimposed on a back porch part by providing a means eliminating a color subcarrier superimposed on the back porch of a horizontal synchronizing signal of a color television signal. CONSTITUTION:A synchronizing separator 1 separates a synchronous signal (b) from a television signal (a) and sends one to a horizontal synchronous signal detector 2 and the other to a vertical blanking detector 8 via a vertical synchronizing detector 7. Output signal (j, k) of a frequency divider 9 with different polarity are fed to a hexadecimal counter 10 and gate circuits 12, 13, output signals (m, n) and an output signal (i) of a pulse generator 6 are fed respectively to a start bit generator 14 and a bit pattern generator 15 to obtain start bit information (o) and coded bit information (p). A signal (l) is fed to a gate circuit 11 to gate signal (g) from a pulse generator 4 and an output signal S is sent to a subcarrier elimination circuit 16 to eliminate a color subcarrier superimposed on the back porch of of a horizontal synchronous signal of the signal (a) other than the vertical blanking period. An information bit mixer 17 superimposes information (o, p) on the eliminated part.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a bank porch portion of a horizontal synchronizing signal of a television signal that is separate from a video signal other than the color subcarrier frequency of a color television signal. A transmission method for composite television signals that superimposes and transmits information signals for use in the purpose of When attempting to transmit information, a method has generally been adopted in which the information is transmitted by superimposing it on a vertical blanking period that is unrelated to the video signal (image signal) of the television signal.

[Problem that the invention seeks to solve]

However, there are only 15 scanning groups of positions in one field where information signals other than television signals during this vertical blanking period are superimposed, and these positions have already been allocated for different purposes. Even if an attempt is made to newly superimpose information signals other than these, the superimposition position is not left.

The reason why these information signals other than video signals are superimposed only during the vertical blanking period is that this period is always at a constant black level, so it is possible to transmit them without being affected by the ever-changing image signal. This is because high reliability is guaranteed.

Further, in the television signal, only a single frequency of a color subcarrier (subcarrier) is superimposed on the back bow portion of the horizontal synchronization signal. This is superimposed on the back-borch portion of all horizontal synchronization pulses except for the vertical equalization pulse and vertical synchronization pulse portions of the vertical blanking period in one screen (525 scanning lines) of the television signal. Therefore, when this color television signal is only transmitted from one point to another, it is inefficient to transmit the color subcarriers superimposed on all parts of the horizontal synchronization signal.

The conventional composite television signal transmission system described above has the problem that it is not possible to transmit a new information signal other than the image signal by superimposing it on a portion other than the vertical blanking period, and it is also inefficient. There was a problem.

[Means for solving problems]

In view of the above points, the present invention was made to solve such problems, and its purpose is to add coded bit information other than color subcarriers to the backboard part of the horizontal synchronization signal of a color television signal. We would like to provide a composite television signal transmission method that can superimpose and transmit the information and also transmit the information only during the vertical blanking period. The object of the present invention is to provide a method for generating an information signal and a circuit format for transmitting the information signal by superimposing it on the back bow portion of a horizontal synchronizing signal.

To achieve such objects, the present invention provides means for separating the synchronization signal of a television signal, means for removing the bank pouch portion of the horizontal synchronization signal of the synchronization signal obtained by this means, and Means for encoding and weighting an information signal other than the subcarrier frequency on the removed bank pouch portion, and means for generating the encoded information signal in synchronization with a horizontal synchronization signal of the television signal. This is what I did.

[Effect]

separating the synchronization signal of a color television signal including color subcarriers, removing or cleaning the color subcarrier frequency superimposed on the backbow part of the horizontal synchronization signal other than the vertical blanking period from the separated synchronization signal; The coded information bits are superimposed on the removed or cleaned part of the back porch, and the coded information bits are alternately used as start bit information and coded bit information at a signal interval that is the frequency of the horizontal synchronization signal divided by 8. The signal obtained by dividing the frequency of the horizontal synchronization signal by 8 is further divided by 1.
A hexadecimal counter counts and generates a waveform that determines at which position in the period of one field of the television signal the coded information bit is superimposed, and the coded bit information is removed or cleaned of backboards. When superimposing the subcarrier on the removed television signal, the pulse amplitude is set to be above the pedestal level, and approximately half the amplitude (peak to peak) of the removed color subcarrier.

〔Example〕

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention, showing only the parts necessary for explanation.

In the figure, 1 is a sync separator that separates the sync signal of a color television signal including color subcarriers, and 2 is a horizontal sync detector that receives the output of sync separator 1 and detects a horizontal sync signal. The horizontal synchronization detector 2 is configured to make the period of the vertical equalization pulse and the vertical synchronization pulse during the vertical blanking period the same as the period of the horizontal synchronization signal because it is two times darker than the horizontal synchronization signal. has been done. 3 is a delay circuit which takes the output of this horizontal synchronization detector 2 as an input and delays the required time; 4 is a color subcarrier (subcarrier ); 5 is a delay circuit which receives the output of the pulse generator 4 and further delays the output pulse by about 0.3 μs; Reference numeral 6 designates a pulse generator which receives the output of the delay circuit 5 and generates a pulse having a pulse width of approximately 2 μs using the rising edge of the output pulse as a trigger.

7 is a vertical synchronization detector that detects the vertical synchronization pulse part from the synchronization signal branched at the output of the synchronization separator 1, and 8 is the output of this vertical synchronization detector 7, and the pulse width is detected using the rising edge of the output waveform as a trigger. A vertical blanking detector detects a vertical blanking period of approximately 83 μs; 9 is a divider that receives the horizontal synchronization signal branched at the output of the horizontal synchronization detector 2 and divides the frequency by 8; 10 is this frequency divider; Using both outputs of the generator 9 as input, each 8-divided waveform is further divided into 16
A hexadecimal counter 11 generates an output when counting times, and 11 is a gate circuit which receives the output of the hexadecimal counter 10 and the output of the pulse generator 4 as inputs. and,
The output of the vertical blanking detector 8 is divided into periods 9 and 16.
They are configured to be supplied to the advance counter 10, respectively.

12 and 13 are gate circuits that receive both outputs of the frequency divider 9 and the output of the hexadecimal counter 10, respectively; 14 is a start circuit that receives the outputs of this gate circuit 12 and the output of the pulse generator 6 as inputs and generates a start bit; bit generator, 15
is a bit pattern generator which receives the output of the gate circuit 13 and the output of the pulse generator 6 as input and generates a bit pattern.

Reference numeral 16 denotes a subcarrier that receives a color television signal including a color subcarrier and the output of the gate circuit 11 and removes or cleans the color subcarrier (subcarrier) superimposed on the backboard portion of the horizontal synchronization signal of the color television signal. The removal circuit 17 is an information bit mixer that mixes the output of this subcarrier removal circuit 16, the output of the start bit generator 14, and the output of the bit pattern generator 15, and this information bit mixer 17 is connected to the subcarrier removal circuit 1B. The start bit information from the start bit generator 14 and the bit pattern generator 15 are added to the back porch portion of the television signal from which the color subcarriers of the punctured porch portion of the horizontal synchronization signal supplied from the horizontal synchronization signal are removed. is configured to superimpose the encoded bit information of the two bits to obtain a composite television signal at the output.

Next, the operation of the embodiment shown in FIG. 1 will be explained with reference to FIGS. 2 and 3.

Figures 2 and 3 are waveform diagrams showing the waveforms of each part of the embodiment shown in Figure 1, where ■DO indicates a video section;
p and VBK indicate vertical blanking intervals. ■EP indicates a vertical equalization pulse, ■SP indicates a vertical synchronization pulse, and C8F indicates a color subcarrier frequency.

First, a color television signal a (see FIG. 2(a)) containing color subcarriers is branched into two, one being supplied to the subcarrier removal circuit 16 and the other being supplied to the synchronous separator 1. Then, this sync separator 1 separates only the sync signal from the color television signal a, as shown in Fig. 2(b).
Obtain a synchronization signal with the waveform shown in .

Next, this synchronization signal is branched into two, one being supplied to the horizontal synchronization detector 2 and the other being supplied to the vertical synchronization detector 7. In this horizontal synchronization detector 2, since the period of the vertical equalization pulse and the vertical synchronization pulse during the vertical blanking period is twice that of the horizontal synchronization signal, this is made the same as the period of the horizontal synchronization signal. As a result, a horizontal synchronizing signal e having a waveform as shown in FIG. 2(e) is obtained. This horizontal synchronizing signal e is branched into two, one being supplied to the delay circuit 3 and the other being supplied to the frequency divider 9. In this delay circuit 3, the horizontal synchronizing signal e is delayed by a time ←) in order to generate a pulse for sampling the color subcarrier superimposed on the pack porch portion of the television signal. A signal f having a waveform as shown in Figure (f) is obtained. Using the rise of the waveform of this signal f (see FIG. 2(f)) as a trigger, the pulse generator 4 generates a pulse with a pulse width of approximately 3.8 μs to remove the color subcarrier superimposed on the υ pack pouch portion. generate g.

Then, the pulse g is further processed by a delay circuit 5 for a time of about 0.3
A signal is obtained by delaying by μs. Finally, this signal is supplied to the pulse generator 6, which triggers the rising edge of this signal to generate a pulse i of 2 μs as shown in FIG. 2(i).

Next, in the vertical synchronization detector 7, which is the other synchronization signal branched into two at the output of the synchronization separator 1, the pulse width of the vertical synchronization pulse is much larger than the pulse width of the horizontal synchronization signal or the vertical equalization pulse. The vertical synchronizing pulse portion is detected by taking advantage of the large size, and a vertical synchronizing signal C having a waveform as shown in the second signal and FIG. 3(C) is obtained. The vertical blanking detector 8 which receives this vertical synchronizing signal C as an input detects a vertical blanking period having a pulse width of about 83 μs using the falling edge of the vertical synchronizing signal C as a trigger. A -signal d having a waveform as shown in Figure (d) is obtained.

On the other hand, the other side of the horizontal synchronization signal e, which has been branched to the output of the horizontal synchronization detector 2, is supplied to the divider 9, where the frequency is divided by 8 to obtain an output signal j as shown in FIG. 3(j). . Although the waveform of the output signal of the other divided-by-8 frequency waveform of this divider 9 is not shown in FIG. 3, it has exactly the opposite polarity of the waveform in FIG. 3(j).

The two-way power signals j, k of the branching device 9 having different polarities like this
is supplied to a hexadecimal counter IOK, and when each 8-frequency divided waveform is further counted 16 times, its output signal l is generated. The waveform of the output signal l is shown in FIG. 3 (5). This output signal 1 rises after counting the output signal j frequency-divided by 8 by the divider 9 16 times, and then falls as the waveform of the vertical blanking detection signal d described above repeats the fall. Also, this 1
Counting by the hexadecimal counter 10 starts at the falling edge of the waveform of the vertical blanking detection signal d.

Next, the signals j and k, which are both outputs of the frequency divider 9, are branched and supplied to the gate circuit 12 and the gate circuit 13, respectively.

On the other hand, these gate circuits 12 and 13 are supplied with the output signal l (see FIG. 3 (a)) from the hexadecimal counter 10, respectively, and receive the signal j and the signal k of the waveform obtained by dividing the frequency of the horizontal synchronization detector C by 8. are gated to obtain output signals m and n having waveforms as shown in FIGS. 2 and 3, respectively. here,
This output signal m is for generating a 1'' continuous information bit string (6 bits in this case) in order to identify a necessary information bit string from a coded information bit string. The output signal m is supplied to the start bit generator 14. Furthermore, the output signal m of the gate circuit 13 is for generating an actually necessary information bit string (in this case, a combination of 6-bit information). Its output signal n is supplied to a bit pattern generator 15.

Here, a pulse generator is used to synchronize the information bit strings output from both the start bit generator 14 and the bit pattern generator 15° to the horizontal synchronization signal, and to adjust the time position so that they can be superimposed on the backboard part of the horizontal synchronization signal. 6 (see FIG. 2(i)) to the start bit generator 14 and the bit pattern generator 15, respectively;
As outputs, start bit information 0 and coded bit information p having waveforms as shown in FIGS. 2(0) and 2(p) are obtained.

Next, in order to remove or clean the color subcarriers superimposed on the bank porch portion of the color television signal a, the output signal g of the pulse generator 4 is supplied to the gate circuit 11, and the output of the hexadecimal counter 10 is signal l
By supplying g to the gate circuit 11, the signal g from the pulse generator 4 is gated, and as its output,
) to obtain a signal S with a waveform as shown in FIG. By supplying this signal S to the subcarrier removal circuit 1B, the color subcarriers superimposed on the backbow portion of the horizontal synchronization signal of the color television signal a are removed or cleaned.

Here, it is during this vertical blanking period that the pulse train g, which is the output of the pulse generator 4 for removing or cleaning the backboard portion of the horizontal synchronizing signal of the television signal, is gated with the vertical blanking detection signal. only,
This is to prevent removal or cleaning of the color subcarrier. That is, the color subcarrier information weighted in the horizontal synchronization signal portion of the vertical blanking period is transmitted while remaining as is.

Next, the output signal q of the subcarrier removal circuit 16 having a waveform as shown in FIG. 2(q) is supplied to the information bit mixer 17. Then, in this information bit mixer 17, various start bit generators 14 are applied to the backbow portion of the television signal from which the color subcarrier of the backbow portion of the horizontal synchronizing signal supplied from the subcarrier removal circuit 1B has been removed. Start bit information 0 and coded bit information p of waveforms as shown in FIG.

As a result, the output of the information bit mixer 17 contains a composite television signal r having a waveform as shown in FIG. 2(r).
can be obtained.

The above explanation has focused on the block configuration shown in FIG. 1, but in order to explain the functional operation of the present invention in more detail,
The following description will focus on the waveform diagrams shown in FIGS. 2, 3, and 4.

First, start bit information O from the start bit generator 14 with a waveform as shown in FIG. 2(0) and coded bit information P from the bit pattern generator 15 with a waveform as shown in FIG. Each waveform will be explained.

This start bit information O is clear from the waveform in FIG. 2 (0) and from the pulse train generated in the period y of the gate output m from the gate circuit 12 shown in FIG. is 8 bits of 01111110'',
The purpose of the first and last bits is to facilitate identification of the start bit information and the coded bit information when the start bit information O is arranged on the same time axis as the coded bit information p.

In other words, the start bit information 0 is always preceded by the "O" bit, and after six consecutive @1 bits are detected, it is always the "O# bit", so the start bit information 0 can be easily identified. , it becomes easy to identify the coded bit information p from a certain bit after the start bit is detected. For example, the coded bit information p for the period 2 of the gate output n from the gate circuit 13 with the waveform shown in Fig. "Add" bit is added,
In this case, the actual information bits are obtained as a combination of 6 bits due to the start bit information that should come before and after these, so from 1 information bit section, 6''-1=3
Five types of information can be obtained.

Therefore, as can be seen from the waveform shown in Figure 3), in one screen (525 scanning lines) of a television signal, there are 16 x 2 = 32 sections in which bit information can be superimposed.
A total of 35x32=1120 types of information can be obtained.

Next, in the waveform diagram of FIG. 4 showing a partially enlarged waveform of the waveform diagram shown in FIG. 2 or 3, C8F indicates the color subcarrier frequency, and PL indicates the pedestal level.

The waveform shown in FIG. 4(a) shows a state in which the color subcarrier frequency C8F is superimposed on the back bow portion of the horizontal synchronizing signal of the color television signal.

The temporal position at which this color subcarrier frequency C8F is superimposed is 0.06H (IH=6
3.75μs, therefore 0.06X63.75μS
= 3.8 μs), so approximately 2.1 μs within this time width
6 μs are allocated for color subcarriers. Therefore, in order to obtain the waveform (2) (see output signal g of the pulse generator 4 in FIG. 1) for removing or extracting this color subcarrier, the delay circuit 3 must use the horizontal synchronizing signal C (see (see (e)) must be delayed by approximately 0.3 μs.

Further, when removing the color subcarrier, the level of the back bow portion is maintained at a constant pedestal level PL. Next, in order to superimpose the encoded bit information of signal 1, which is the output of the pulse generator 6, on the pedestal portion of this back borch from which the color subcarrier has been removed or cleaned, a coded pulse is inserted in the middle of the cleaned back borch portion. In order to superimpose the color subcarriers removed or cleaned, the pulse g (see FIG. 4 (b)) is delayed by about 0.1 μs in the delay circuit 5, and then the pulse h is
A pulse with a pulse width of about 2 μs is generated using the rising edge (see FIG. 4(h)) as a trigger. This pulse is the start bit information 0 of the waveform shown in FIG. 4(0). When this start bit information O is superimposed on the television signal q (see FIG. 4 (q)) from which the backboard has been removed or cleaned, its pulse amplitude is equal to the pedestal level P.
The peak to peak of the removed color subcarrier is set to be approximately half of the peak to peak of the removed color subcarrier. By superimposing coded bit information in this way, when transmitting a composite television signal on which coded bit information is superimposed, it is possible to transmit the composite television signal without adversely affecting other image signals, or to transmit the composite television signal after transmission. When a synchronous signal is separated from a signal for signal processing, synchronous separation can be performed very easily.

〔Effect of the invention〕

As explained above, according to the present invention, there are provided a means for separating a synchronizing signal from a television signal, a means for removing a packed pouch portion of a horizontal synchronizing signal of a synchronizing signal obtained by this means, and a means for separating a synchronizing signal from a television signal; The system includes means for encoding and superimposing an information signal other than the subcarrier frequency on the removed pack pouch portion, and means for generating the encoded information signal synchronized with the horizontal synchronization signal of the television signal. , coded bit information other than the color subcarrier can be superimposed and transmitted in the pack pouch portion of the horizontal synchronization signal of the color television signal, and the color subcarrier can also transmit that information only during the vertical blanking period. The practical effects are extremely large.

[Brief Description of the Drawings] Figure 1 is a block diagram showing an embodiment of the present invention, Figure 2 is a block diagram showing an embodiment of the present invention.
FIG. 3 is a waveform diagram showing waveforms of various parts to explain the operation of FIG. 1, and FIG. 4 is a waveform diagram showing a partially enlarged waveform of the waveform shown in FIG. 2 or 3. 1-...Synchronization separator, 2...Horizontal synchronization detector, 3
, 5... fist delay circuit, 4.6... pulse generator,
7... Vertical synchronization detector, 8... Vertical blanking detector, 9ψ... Frequency divider, 1G---hexadecimal kakunta, 11 to 13... Working gate circuit, 14- ...Start bit occurs! , 15... Bit pattern generator, 16... Subcarrier removal circuit, 17... Information bit mixer.

Claims (1)

[Claims] means for separating a synchronization signal of a television signal; means for removing a backbow portion of a horizontal synchronization signal of a synchronization signal obtained by the means; and encoding an information signal other than a subcarrier frequency in the backbow portion removed by the means. 1. A composite television signal transmission system, comprising: means for converting and superimposing the coded information signal; and means for generating the encoded information signal in synchronization with a horizontal synchronization signal of the television signal.