JPH06311492A - Data transmission equipment - Google Patents

Abstract

PURPOSE:To transmit digital data in multiplexing by executing amplitude modulation and/or phase modulation to a color burst signal. CONSTITUTION:A video IF signal inputted from an input terminal 1 is converted into a digital signal by an A/D converter 3, and is inputted to a scrambling part 5. Then, the signal is scrambled by the control of a CPU 7, and is outputted to a data multiplexing part 9. Besides, the output of key data for canceling scramble is multiplexed by executing the amplitude modulation or the phase modulation to the color burst signal by the data multiplexing part 9. Next, the signal is converted into an analog signal by a D/A converter 11, and is modulated to a prescribed TV channel by an RF modulating part 13, and is outputted through an output terminal 15, and is transmitted to each subscriber through a cable. Thus, the digital data is multiplexed to a television signal by modulating the color burst signal by the amplitude modulation or the phase modulation or the modulating method of the combination of both the modulations.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission device that multiplexes data on a television signal and transmits it.

[0002]

2. Description of the Related Art Conventionally, a center is connected to a large number of terminal devices via cables, and a video signal is sent from the center to these large numbers of terminal devices, for example, a cable television (hereinafter simply referred to as CATV). There is a system. In this CATV system or the like, pay broadcasting is performed in which a fee is charged for viewing a predetermined channel, program, etc. Therefore, in a television signal transmitting / receiving apparatus, a video signal is scrambled and the signal is also descrambled. A method is used in which key data for scrambling is multiplexed with an audio signal and transmitted.

FIG. 10 is a block diagram showing the structure of a transmitter in a conventional CATV system. In FIG. 10, the video IF signal input through the terminal 101 is
It is input to the scramble unit 103. In the scramble unit 103, for example, a synchronous compression circuit or the like is used, and the horizontal synchronizing period is suppressed by the timing signal from the timing generator unit 107.

A signal indicating the timing of suppressing the horizontal synchronizing period is multiplexed as a key data signal with the audio IF signal input from the terminal 102 in the AM modulator 104 and output.

The audio IF signal in which the video IF signal and the key data signal are thus multiplexed is modulated into a predetermined TV channel by the RF modulator 105 and transmitted from the output terminal 106 to each subscriber through a cable.

FIG. 11 is a block diagram showing the structure of a conventional CATV converter. In FIG. 11, the television signal transmitted through the cable connected to the input terminal 201 is received by the tuner unit 202, converted into a video IF signal and an audio IF signal, and input to the descramble unit 204. The audio IF signal is also input to the key signal extracting unit 203, and the key signal multiplexed here is extracted.

Based on the extracted signal, the descrambling unit 204 performs a descrambling operation for reproducing the suppressed synchronous portion of the video IF signal, and the RF modulating unit 20.
Output terminal 206 after being modulated to a predetermined TV channel at 5
Input to the television receiver. Thus, C
In the ATV system, as a method of transmitting a key signal for descrambling a scrambled signal on the receiving side, a method of subjecting a voice IF signal to AM modulation and multiplex transmission is often used.

[0008] At present, in the United States, an overlapping part of a television receiver and a converter, for example, a tuner and an IF circuit are removed from the converter so that the television receiver can be connected only as a descrambling function. EIA563 (IS-15)
Multiport based on is used.

FIG. 12 is a block diagram showing the configuration of a conventional multi-port compatible television receiver and converter unit. In FIG. 12, a television signal input through the input terminal 301 passes through the RF circuit 302, is connected by the F type connectors 303 and 308, is received by the tuner unit 309 of the television receiver 314, and is further imaged. / The audio demodulation unit 311 demodulates to a baseband video signal and audio signal.

Further, this signal is transmitted to the television receiver 3
14 is descrambled under the control of the CPU 307 based on the subscriber data input to the descramble unit 304 via the multiports 310 and 305 connecting the converter unit 300 and the converter unit 300 and demodulated by the downlink data demodulation unit 306. It is again input to the television receiver 314 and is displayed on the display 313.

However, in the multi-port (EIA563) compatible system as described above, since the video signal and the audio signal, which are baseband signals, are input to the converter unit 300 side, the audio signal as in the conventional CATV system. There is a problem that the method of multiplexing and transmitting key data cannot be used.

[0012]

As described above, in the multi-port (EIA563) compatible system, there is a problem that key data and the like cannot be multiplexed and transmitted in a voice signal.

An object of the present invention is to provide a data transmission device capable of transmitting key data and the like by using a color burst signal.

[0014]

In order to achieve the above object, the first invention of the present application is a data transmission device capable of transmitting a television signal, and is amplitude modulation, phase modulation, or a modulation method combining these. The gist of the present invention is to have a multiplexing means for modulating the color burst signal to multiplex the digital data with the television signal and a transmitting means for transmitting the television signal multiplexed by the multiplexing means.

The second invention of the present application is a data transmitting apparatus capable of transmitting a television signal, wherein the color burst signal is amplitude-modulated to multiplex digital data into the television signal, and the average of the color burst signal is obtained. The gist is to have a multiplexing means for modulating the amplitude so that the amplitude is constant, and a transmitting means for transmitting the television signal multiplexed by the multiplexing means.

The third invention of the present application is a data receiving apparatus capable of receiving a television signal in which digital data is multiplexed by modulating a color burst signal by an arbitrary method in a data transmitting apparatus, Receiving means for receiving the signal, extracting means for extracting the digital data multiplexed on the color burst signal of the television signal received by the receiving means, and the color burst signal modulated by the data transmitting device before the modulation. The gist is to have demodulation means for demodulating into amplitude and phase.

Further, a fourth invention of the present application is a data receiving device capable of receiving a television signal in which digital data is multiplexed by phase-modulating a color burst signal in the data transmitting device, the television signal being received. Receiving means, extracting means for extracting digital data which is multiplexed by phase modulation on the color burst signal of the television signal received by the receiving means, and the phase modulated color burst signal is multiplexed in the vertical blanking period. And a replacing means for replacing the color burst signal for reference with the selected color burst signal.

[0018]

In the data transmitting apparatus of the first invention of the present application, the color burst signal is modulated by the amplitude modulation or the phase modulation by the multiplexing means or the modulation method in which these are combined to multiplex the digital data. Then, the transmitting means transmits the multiplexed television signal.

Further, in the data transmitting apparatus of the second invention of the present application, the color burst signal is amplitude-modulated by the multiplexing means to multiplex the digital data into the television signal, and the average amplitude of the color burst signal becomes constant. Modulate the amplitude. The transmitting means transmits the multiplexed and modulated television signal.

Further, in the data receiving apparatus of the third invention of the present application, the receiving means receives the television signal in which the digital burst data is multiplexed by modulating the color burst signal on the data transmitting apparatus side by an arbitrary method. The extracting means extracts the digital data multiplexed with the color burst signal of the received television signal. Further, the modulated color burst signal is demodulated by the demodulation means into the amplitude and phase before modulation.

Further, in the data receiving device of the fourth invention of the present application, when the receiving means receives the television signal in which the digital burst data is phase-modulated on the data transmitting device side and the digital data is multiplexed, this is received. Extraction means extracts the digital data multiplexed with the color burst signal of the television signal by phase modulation. Further, the phase-modulated color burst signal is replaced by the replacing color burst signal with the reference color burst signal multiplexed in the vertical blanking period.

That is, in the data transmitting apparatus and the receiving apparatus of the present invention, on the transmission side of the television signal transmitting / receiving system, the color burst signal in the television signal is modulated and the television signal in which the digital data is multiplexed is used as the transmission path. The television signal is sent out, and the television signal is received at the receiving side, and the digital data multiplexed by the color burst signal is extracted to transmit the digital data.

As a result, since digital data such as timing data is multiplexed and transmitted by a color burst signal by amplitude modulation, phase modulation, or a combination method thereof, multiport (EIA563) compatible. Digital data can be transmitted to the system as well.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a television signal transmitter showing an embodiment of the present invention.

The video IF signal input from the input terminal 1 is converted into a digital signal by the A / D converter 3,
It is input to the scramble unit 5. And this signal is CP
The data is scrambled by the control of U7 and output to the data multiplexing unit 9. Further, the output of the key data for descrambling is multiplexed by the data multiplexer 9 by performing amplitude modulation or phase modulation on the color burst signal. Then D /
The analog signal is converted by the A converter 11 and modulated into a predetermined TV channel by the RF modulator 13, and the output terminal 1
5 and is transmitted to each subscriber through a cable.

FIG. 2 is a block diagram showing the configuration of an embodiment of the data multiplexer 9 of FIG.

The data multiplexer 9 multiplexes the key data output for descrambling by subjecting the color burst signal to amplitude modulation and phase modulation. This data multiplexing unit 9
It is composed of a multiplier 91, a selector 93, and an AND circuit 95. Here, an example of multiplexing binary data of "0" and "1" is shown.

FIG. 3 is a timing chart showing the timing of the color burst signal and the burst gate signal. In FIG. 3, the key data input from the CPU 7 is
It is gated by the AND gate 95 with the burst gate signal, the key data is output to the selector 93 only during the color burst signal period, and '0' is output during the other periods.

For example, since the level of the color burst signal of the video signal input to the multiplier 91 is 40IRE, x1 is selected by the selector 93 except when the key data is "0" and the color burst signal period. , The level of the signal output from the multiplier 91 does not change, but when the key data is “1”, × 3/4 is selected,
The level of the color burst signal output from the multiplier 91 is modulated to 30IRE. In this way, it is possible to multiplex digital data by modulating a color burst signal with a relatively simple structure.

FIG. 4 is a block diagram showing the configuration of a television receiver which is an embodiment of the present invention. In FIG. 4, the signal input from the cable connected to the input terminal 19 is the tuner section 21 of the television receiver 17.
And is further demodulated by the video / audio demodulation unit 23 into baseband video signals and audio signals. This signal is
It is supplied to the multi-port compatible converter 45 via the multi-port 29. In the multi-port compatible converter 45, first, the input signal is converted into a digital signal by the A / D converter 35, and the key data multiplexed on the color burst signal is extracted by the data extraction unit 37.

The downlink data demodulation section 31 has an input terminal 19
The input signal is branched and input via the, and the downlink data demodulation unit 31 demodulates the subscriber data from the input signal. The CPU 33 collates the key data with the subscriber data to determine whether or not descrambling is possible, and inputs a signal to the descrambling unit 39.

Further, the output of the descrambling unit 39 is input to the burst correcting unit 41, and after returning to the state before modulating the color burst signal based on the previously extracted key data, the D / A converter 43 Is converted into an analog signal and input to the television receiver 17 again via the multiport 29.

In the burst correction unit 41, the modulated color burst signal may be replaced with the reference color burst signal multiplexed in the vertical blanking period to restore the state before the modulation.

The signal input from the multi-port 29 is subjected to video signal processing such as Y / C separation in the video processing unit 27, and then a video is displayed on the display 25. By thus modulating the color burst signal and transmitting the data, key data can be transmitted / received even in a multiport in which signals are transmitted / received with a baseband signal.

The color burst signal (hereinafter abbreviated as burst signal) modulation method in the present invention will be described in detail below. First, a method of modulating the amplitude of a burst signal and transmitting digital data will be described as a first embodiment.

FIG. 5 is an explanatory diagram showing an embodiment of the case where the amplitude modulation of the burst signal in the present invention is (1 bit) data.

As shown in the figure, the reference amplitude of the burst signal in a normal television signal is 40 IRE. For example, the 40 IRE level is set to "0", the 30 IRE level smaller than 40 IRE is set to "1", the burst signal level is modulated by the data multiplexing unit 9 in FIG. It becomes possible to transmit.

On the receiving side, the data extraction unit 37 shown in FIG.
The burst signals are compared in amplitude to extract the multiplexed digital data. In this case, "0" is detected when the burst signal level is 40 IRE level, and "1" is detected when the burst signal level is 30 IRE level and output to the CPU 33.

FIG. 6 is an explanatory diagram showing an embodiment of the case where the amplitude modulation of the burst signal in the present invention is (2-bit) data.

If the burst signal level is modulated to 30, 40, 50, 60 IRE as shown in FIG.
It is possible to transmit 2-bit data with one burst signal. Thus, when transmitting 1-bit data by one burst signal, a data transmission rate of about 15 Kbps and about 30 Kbps can be secured when transmitting 2-bit data, and key data and program ID for descrambling can be secured. The transmission rate is sufficient for transmission.

Furthermore, by modulating the level of the burst signal into a large number of levels within the range that can be detected by the receiving side, a large number of bits can be multiplexed and a large amount of data such as a program guide can be transmitted. Become.

Next, as a second embodiment, a method of modulating the phase of a burst signal and transmitting digital data will be described.

FIG. 7 is an explanatory diagram showing an embodiment of the case where the phase modulation of the burst signal in the present invention is (2-bit) data.

As shown in the figure, the phase of the burst signal is 0 °, 90 °, 180 depending on the digital data '00''01''10''11' on the transmitting side, for example.
It is supposed to be changed in four ways of 270 ° and 270 °. Then, 2-bit data transmission per burst signal becomes possible. On the receiving side, the phases of these four types of modulated burst signals are detected, and the corresponding digital data '0
It is possible to obtain 0 ″ 01 ″ 10 ″ 11 ′.

Even if the phase of the burst signal is modulated in this way, digital data can be transmitted, and if 1 bit of digital data is assigned to one burst signal as in the first embodiment, about 15 Kbps, 2 If bits are allocated, a data transmission rate of about 30 Kbps can be obtained. Moreover, by using it together with the first embodiment,
A large amount of data can be transmitted.

FIG. 8 shows another embodiment of the present invention,
It is a block diagram which shows the structure of a television receiver.

In the figure, the same components as those shown in FIG. 4 are designated by the same symbols, and the difference from the embodiment of FIG. 4 is that the burst correction unit 41 is removed.

Originally, in the television receiver, the burst signal is ACC (Auto Color Conto).
roll) circuit, APC (Auto Phase Con)
control) circuit. The former detects the average level of the burst signal and controls the level of the color signal,
The latter is used as a reference for the oscillator for reproducing the color subcarrier based on the phase information of the burst signal. As described above, the amplitude information and the phase information of the burst signal are both necessary information for the television receiver, and the modulated information is the final information in the first and second embodiments so as not to affect them. In order to return to the state before modulation, a burst correction unit 41 is added.

In the embodiment shown in FIG. 8, the ACC circuit detects the average level of the burst signal and controls the level of the color signal, so that
The burst correction unit 41 can be removed by the method of multiplex transmission of digital data by amplitude modulation as in the first embodiment.

An example in which data transmission is possible even with the circuit thus simplified is shown below.

FIG. 9 is an explanatory view showing another embodiment of the amplitude modulation of the burst signal in the present invention.

For example, the original level of the burst signal is 4
Since it is 0IRE, if modulation is performed so that two levels of 50IRE and 30IRE are switched at the half of the burst signal period as shown in the figure, 1-bit data transmission is possible as in the first embodiment. , About 15 Kbp
A transmission rate of s can be obtained, and a circuit for returning the modulated burst signal to the original state is unnecessary, and the circuit can be simplified.

As a matter of course, the burst signal is 1
Since 8 cycles are inserted per line, 1
If 1 bit is allocated for each cycle, data of up to 8 bits can be multiplexed with one burst signal, approximately 120 Kbp
s data transmission becomes possible.

Further, although the present embodiment has been described by taking the multi-port as an example, the method of modulating the burst signal of the present invention to transmit the data is not limited to the multi-port, but a normal CA.
It can be used for data transmission in TV systems, terrestrial broadcasting, satellite broadcasting, etc. Further, the data is not limited to key data, and various key information in encryption, billing information used for billing, etc. It goes without saying that it may be data.

[0056]

As described above, according to the present invention, it is possible to multiplex and transmit digital data by a color burst signal by amplitude modulation, phase modulation, or a combination method thereof, so that a television can be transmitted. A high-rate data transmission line can be secured in the John signal.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a television signal transmitter according to the present invention.

FIG. 2 is a block diagram showing an embodiment of the data multiplexing unit shown in FIG.

FIG. 3 is a timing diagram showing timings of a color burst signal and a burst gate signal.

FIG. 4 is a block diagram of a television receiver showing an embodiment of the present invention.

FIG. 5 is an explanatory diagram showing an embodiment in which amplitude modulation of a burst signal according to the present invention is 1-bit data.

FIG. 6 is an explanatory diagram showing an embodiment in which amplitude modulation of a burst signal in the present invention is 2-bit data.

FIG. 7 is an explanatory diagram showing an embodiment in which the phase modulation of the burst signal according to the present invention is 2-bit data.

FIG. 8 is a block diagram of a television receiver showing another embodiment of the present invention.

FIG. 9 is an explanatory diagram showing another embodiment of amplitude modulation of a burst signal according to the present invention.

FIG. 10 is a block diagram of a transmitter of a CATV system showing a conventional example.

FIG. 11 is a block diagram of a CATV converter showing a conventional example.

FIG. 12 is a block diagram of a conventional multi-port television receiver and converter unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Input terminal, 3 ... A / D converter, 5 ... Scramble part, 7 ... CPU, 9 ... Data multiplexing part, 11 ... D / A converter, 13 ... RF modulator, 15 ... Output terminal, 17 ... TV John receiver, 19 ... Input terminal, 21 ... Tuner section, 2
3 ... video / audio demodulation unit, 25 ... display, 27 ... video processing unit, 29 ... multi-port, 31 ... downlink data demodulation unit, 33 ... CPU, 35 ... A / D converter, 37 ... data extraction unit, 39 ... Descramble unit, 41 ... Burst correction unit, 43 ... D / A converter, 45 ... Multiport compatible converter, 91 ... Multiplier, 92 ... Selector, 93 ... AND
circuit.

Claims (4)

[Claims] 1. A data transmission device capable of transmitting a television signal, wherein a color burst signal is modulated by amplitude modulation, phase modulation, or a combination method thereof, and digital data is multiplexed on the television signal. A data transmitting apparatus comprising: a multiplexing means and a transmitting means for transmitting a television signal multiplexed by the multiplexing means. 2. A data transmitting device capable of transmitting a television signal, wherein a color burst signal is amplitude-modulated to multiplex digital data into the television signal and the average amplitude of the color burst signal is kept constant. A data transmitting apparatus comprising: a multiplexing means for modulating the amplitude; and a transmitting means for transmitting a television signal multiplexed by the multiplexing means. 3. A data receiving device capable of receiving a television signal in which digital data is multiplexed by modulating a color burst signal by an arbitrary method in a data transmitting device, and a receiving means for receiving the television signal. Extracting means for extracting digital data multiplexed on the color burst signal of the television signal received by the receiving means, and demodulating the color burst signal modulated by the data transmitting device into amplitude and phase before modulation. A data receiving apparatus comprising: a demodulating unit. 4. A data receiving device capable of receiving a television signal in which digital data is multiplexed by phase-modulating a color burst signal in a data transmitting device, the receiving means receiving the television signal, and the receiving means. Extracting means for extracting digital data multiplexed by phase modulation on the color burst signal of the television signal received by the means, and color burst for reference in which the phase modulated color burst signal is multiplexed in the vertical blanking period A data receiving apparatus comprising: a replacing unit that replaces a signal.