JPH09284733A - Communication device and communication system - Google Patents

Abstract

(57) Abstract: In a system in which data is modulated into a video signal, multiplexed and transmitted, and the data is extracted and demodulated at the receiving side, data modulation, demodulation speed, multiplexing period, separation period, etc. can be arbitrarily set. To be able to change to. In a transmitting terminal 10, a video signal from a camera 11 and data generated by a CPU 12 and modulated by a modulator 13 are multiplexed by a multiplexer 14 and sent to a transmission line 1. At this time, the modulation speed and the horizontal line to be multiplexed are controlled. In the receiving terminal 20, the signal separation unit 22 separates the video signal and the data from the received signal, and the data is demodulated by the demodulation unit 24. At this time, the demodulation speed and the horizontal line for separating the data are controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device such as a terminal and a communication system suitable for use in a case where data is multiplexed on a video signal for communication.

[0002]

2. Description of the Related Art Conventionally, there is a system for transmitting a signal in which data such as characters is multiplexed with a video signal and receiving the signal to separate the video signal and the data, such as a character broadcast.

[0003]

However, the above-mentioned conventional system multiplexes the modulated data in a specific period (a part of the vertical blanking interval) of the video signal, and only the specific period is received on the receiving side. It demodulates and extracts data. That is, the data modulation rate, the multiplexing period, etc. have already been determined, and they cannot be changed depending on the data amount, line quality, etc.

The present invention has been made in order to solve such a problem, and communication in which variable speed, modulation timing, demodulation speed, demodulation timing and the like can be controlled when data is multiplexed and transmitted on a video signal. An object is to obtain a device and a communication system using this communication device.

[0005]

According to another aspect of the present invention, there is provided a communication device for modulating input data, and multiplexing for multiplexing the modulated data with an input video signal and outputting the multiplexed video signal. Means and control means for controlling at least one of the modulation rate and the period for multiplexing the data.

In the communication device according to the third aspect of the present invention, a separating means for separating the video signal and the modulated data from the received signal, a demodulating means for demodulating the separated modulated data, the demodulating speed and A control means for controlling at least one of the periods for separating the modulated data is provided.

In the communication system according to the present invention, the modulating means for modulating the input data, the multiplexing means for multiplexing the modulated data with the input video signal and outputting the multiplexed signal, and the modulation speed And a first communication device having first control means for controlling at least one of the periods for multiplexing the data, transmission means for transmitting a signal output from the first communication device, and Receiving the signal, separating means for separating the video signal and the modulated data from the received signal, demodulating means for demodulating the separated modulated data, separating the demodulation speed and the modulated data. And a second communication device having a second control means for controlling at least one of the operating periods.

[0008]

According to the communication device of the present invention, at least one of the modulation speed and the multiplexing period can be controlled when the data is modulated and multiplexed on the video signal and output.

According to the communication device of the invention of claim 3,
When the video signal and the modulated data are separated from the received signal and the data is demodulated, at least one of the demodulation speed and the data separation period can be controlled.

According to the communication system of the present invention, in the first device, at least one of the modulation rate multiplexing periods is controlled when the data is modulated, multiplexed with the video signal and sent to the transmission means. In addition, the second communication device can separate the video signal and the modulated data from the received signal, and when demodulating the data, can control at least one of the demodulation speed and the data separation period. it can.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of the present invention. In FIG. 1, 1 is a transmission line, 10 is a transmitting side terminal, and 20 is a receiving side terminal. In the transmission side terminal 10, 11 is a camera, 12 is a control CPU, 13 is a data modulator (including a modulation controller), 14 is a signal multiplexer, and 15 is an output unit. At the receiving terminal 20, 2
Reference numeral 1 is a reception unit, 22 is a signal separation unit, 23 is a monitor, 24 is a demodulation unit (including a demodulation control unit), and 25 is a control CPU.

Next, the operation will be described. Sending terminal 1
At 0, the video signal picked up by the camera 11 is sent to the multiplexing unit 14. On the other hand, the data generated by the CPU 12 is modulated by the modulation unit 13, and this modulated data signal is sent to the multiplexing unit 14 and multiplexed with the video signal, and the output unit 1
It is sent to the transmission line 1 via 5. Where the CPU
By the control of 12, the data modulation speed, the modulation timing, etc. are set.

In the receiving side terminal 20, the signal received from the transmission line 1 via the receiving section 21 is received by the signal separating section 2.
The video signal and the modulated data signal are separated by 2, and the video signal is input to the monitor 23 and displayed. The modulated data signal is input to the demodulation unit 24 where the data is demodulated and CP
Handed over to U25. Here, under the control of the CPU 25,
The data demodulation speed, the demodulation timing, etc. are set, and the data is demodulated according to this.

FIG. 2 shows a block diagram in which the modulator 13 (including the modulation controller) and the demodulator 24 (including the demodulator) are combined. In addition, this block diagram is shown in FIG.
Used in a terminal in which the receiving terminal 20 and
A common CPU is used for U12 and U25.
In FIG. 2, 101 is a CPU interface, 10
2 is an address generator, 103 is a transmission / reception buffer, 104 is a modulation control unit, 105 is a CRC addition unit for adding a CRC check code, 106 is a demodulation control unit, 10
Reference numeral 7 is a CRC detector that detects a CRC error.

Next, the operation will be described. The CPU interface 101 exchanges commands, data, status, etc. with the control CPU. CP command from the CPU for modulation speed and modulation timing (modulation line etc.)
The signal is set in the modulation control unit 104 via the U interface 101, and the control signal (TxVI) is synchronized with the vertical and horizontal synchronization signals TxVD, TxHD, the clock signal TxCLK, and the like.
A signal such as a DS gate) is generated. The transmission data input from the CPU is temporarily stored in the transmission buffer 103 according to the address generated by the address generator 102, and then read by the address generator 102 according to a control signal from the modulation control unit 104 to perform CRC. Addition part 1
A CRC code is added at 05 and output as VIDSTx data.

On the receiving side, the demodulation speed from the CPU,
A command of demodulation timing (demodulation line or the like) is set in the demodulation control unit 106 via the CPU interface 101, and the reception control signal is synchronized with the reception synchronization signals such as the vertical and horizontal synchronization signals RxVD, RxHD and the clock signal RxCLK. A signal such as (RxVIDS gate) is generated. The modulated data signal VIDSRx data separated by the signal separation unit 22 is temporarily stored in the reception buffer 103 according to the address generated by the address generator 102 after the CRC detection unit 107 checks for an error. Then, the data received by the designation of the address generator 102 is read out via the CPU interface 101.

The CPU interface 1 rather than the CPU
By independently sending a command to the modulation control unit 104 and the demodulation control unit 106 via 01, data can be modulated and demodulated on any line independently.

FIG. 3 shows a timing chart of each signal. In FIG. 3A, a, b, and c are composite synchronization signals Csyn.
c, a control signal TxVIDS gate in the vertical blanking interval (Vdelay, Vwidth) and a video signal in which data is multiplexed. It is shown that data is modulated in synchronization with a synchronizing signal of a video signal, and this modulated data signal is multiplexed with the video signal. Here, the data is modulated, the multiplexing period is matched with the synchronizing signal of the video signal, and the number of lines to be multiplexed is set as shown in the figure. In FIG. 3B, d and e show the relationship between the data multiplexed on one horizontal line of the video signal and other signals.
Although PCM modulation is used as a data modulation method, any other modulation method may be used. The timing of demodulation is also the same.

FIG. 4 shows a second embodiment, showing a terminal to which external synchronization can be applied. In FIG. 4, 31 is a camera, 32 is a control CPU, 33 is a modulation / demodulation unit (including a modulation control unit and a demodulation control unit), 34 is a multiplexing unit, 35 is an output unit, 36 is a receiving unit, and 37 is a signal. It is a separation unit.

Next, the operation will be described. The video signal input from the camera 31 is sent to the multiplexing unit 34. On the other hand, the data generated by the CPU 32 is modulated by the modulator / demodulator 33, and the modulated data signal is time-division multiplexed by being switched to the video signal by the multiplexer 34 and output from the output unit 35.

A signal transmitted from another terminal is input from the receiving unit 36, and separated by a signal separating unit 37 into a video signal (here, a composite synchronizing signal) and a modulated data signal. The modulated data signal is demodulated by the modulator / demodulator 33 and then input to the CPU 32. The separated video signal (composite sync signal) is input to the camera 31 for external synchronization with the camera 31.

Here, the signal output from this terminal includes
Since the video signal input from the camera 31 is included, the data area that can be multiplexed is limited to the vertical blanking interval of the video signal. On the other hand, since the signal received is a composite synchronizing signal (black burst signal or the like) for externally synchronizing the camera 31, the period in which the data can be multiplexed is not limited to the vertical blanking interval, but the vertical synchronizing period. It is possible to multiplex data in all areas except the period. this is,
This is possible by setting the modulation control unit and the demodulation control unit included in the modulation / demodulation unit 33 independently.

Further, as a third embodiment, since the data multiplex area can be arbitrarily set and the communication can be performed, the data multiplex area can be communicated while dynamically changing after negotiation with each other. Is also possible.

In the above description, the demodulation control section sets the reception area on the reception side. However, the signal separation section is provided with an area setting section, and only the set area is separated and data is sent to the demodulation section. It is also possible.

[0025]

As described above, the present invention makes it possible to control at least one of the modulation speed and the multiplexing period when the transmitting side modulates and multiplexes the video signal data. On the receiving side, when the multiplexed data is separated and demodulated, the demodulation speed and the separation period are controlled to take out the multiplexed data. Therefore, according to the present invention, it becomes possible to control the modulation / demodulation speed and dynamically allocate the data communicable area in accordance with the requirements of the system, the amount of generated data, the quality of the line, and the like.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a block diagram in which a modulation unit and a demodulation unit are combined.

FIG. 3 is a timing chart of signals.

FIG. 4 is a block diagram showing a second embodiment of the present invention.

[Explanation of symbols]

 1 Transmission Line 10 Transmission Terminal 11 Camera 12 CPU 13 Modulation Section 14 Multiplexing Section 15 Output Section 20 Receiving Terminal 21 Reception Section 22 Signal Separation Section 24 Demodulation Section 25 CPU 31 Camera 32 CPU 33 Modulation / Demodulation Section 34 Multiplexing Section 35 Output Section 36 Reception unit 37 Signal separation unit 103 Transmission and reception buffer 104 Modulation control unit 106 Demodulation control unit

Claims (9)

[Claims] 1. A modulation means for modulating input data, a multiplexing means for multiplexing the modulated data with an input video signal and outputting the multiplexed signal, and a modulation speed and a period for multiplexing the data are small. A communication device including a control unit that controls one of them. 2. The communication device according to claim 1, wherein the control means controls a period in which the data is multiplexed in units of horizontal lines of the video signal. 3. A separation means for separating a video signal and modulated data from a received signal, a demodulation means for demodulating the separated modulated data, and a period for separating the demodulation speed and the modulated data. And a control means for controlling at least one of the communication devices. 4. The communication device according to claim 3, wherein the control means controls a period for separating the modulated data in units of horizontal lines of the video signal. 5. The communication device according to claim 3, wherein the video signal is a composite synchronizing signal. 6. A modulation means for modulating input data, a multiplexing means for multiplexing the modulated data with an input video signal and outputting the same, a modulation speed and a period for multiplexing the data are small. A first communication device having first control means for controlling one of them, a transmission means for transmitting a signal output from the first communication device, and a reception signal for receiving the transmitted signal. From the video signal and the modulated data, the demodulating means for demodulating the separated modulated data, and the demodulation speed and at least one of the periods for separating the modulated data A communication system comprising: a second communication device having a second control means. 7. The communication system according to claim 6, wherein the first control means controls the period for multiplexing the data in units of horizontal lines of the video signal. 8. The communication system according to claim 6, wherein the second control means controls a period for separating the modulated data in units of horizontal lines of the video signal. 9. The communication system according to claim 6, wherein the video signal is a composite synchronizing signal.