JPH0620312B2 - Character multiple insertion device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a television signal transmission device, and more particularly to a television program signal in which a character or graphic signal of a different medium is added to a television program signal during a vertical blanking period. The present invention relates to a superimposed character multiple inserter device.

[Conventional technology]

FIG. 2 is a block diagram showing a circuit configuration of a conventional example of this type of character multiplex inserter device.

The gain control circuit 4 inputs the composite video signal 1 of the television program signal and the signal 2 of the different type of media, and outputs the signal 2 of the different type of media to a predetermined position of the composite image signal 1 according to the gain control of the separately input key signal. And is output as a composite video signal 3. The key signal generation circuit 105
A key signal is output according to the separated sync signal input from the sync discontinuity detection circuit 106 and the detection signal in the sync discontinuity state.

Next, the outline of the configuration of the synchronization discontinuity detection circuit 106 will be described. The sync signal separation circuit 7 generates and outputs a separation sync signal from the input composite video signal 1. The 1H delay circuit 8 delays the separated sync signal input from the sync signal separation circuit 7 by one horizontal scanning period and outputs the delayed sync signal. The comparison circuit 9 is composed of an exclusive OR circuit, and compares the separation synchronization signal input from the synchronization signal separation circuit 7 with the separation synchronization signal input from the 1H delay circuit 8 and delayed by one horizontal scanning period. hand,
It is output when the two are different, that is, when the discontinuity of the horizontal synchronizing signal occurs. The pulse generation circuit 11 receives the separated sync signal from the sync signal separation circuit 7 and generates a pulse signal synchronized with this. The clock generation circuit 110 generates a color subcarrier signal (3.58 MHz) for demodulating a color signal from a color burst in the composite video signal 1 by a burst control oscillator (hereinafter referred to as a BCO circuit) included therein. The storage circuit 13 stores the vertical synchronizing signal during the vertical blanking period of the composite video signal 1 and before and after the vertical synchronizing signal (1H to 10H).
The unique signal pattern output from the comparison circuit 9 during the period is stored. The address counter 12 inputs the output signals of the pulse generation circuit 11 and the clock generation circuit 110, and reads the stored contents of the storage circuit 13 for each period from 1H to 10H of the composite video signal 1. The comparison circuit 15 is composed of an exclusive OR circuit, and by constantly comparing the output of the comparison circuit 9 with the data read from the storage circuit 13, it outputs when they are different.

Therefore, the sync discontinuity detection circuit 106 detects when a discontinuity occurs in the horizontal and vertical sync signals in the composite video signal 1 and detects the discontinuity, and outputs the key signal output from the key signal generation circuit 5. Since it is stopped, superposition of signals of different media by the gain control circuit 4 is prevented.

[Problems to be solved by the invention]

The above-described conventional character inserter device detects the out-of-phase of the horizontal and vertical sync signals, but it does not detect the out-of-phase of the color subcarrier signal, and thus is incomplete as a character multiplex inserter device. There is.

[Means for solving problems]

The character multiplex inserter device of the present invention is provided in the sync discontinuity detection circuit, detects the phase of the color subcarrier signal reproduced from the color burst in the input composite video signal, and the phase error is out of the set range. When the color subcarrier phase error detection means for outputting the detection signal and the detection signal output from the color subcarrier phase error detection means are input, the key signal is stopped to prevent the superimposition of signals of different media. It has a key signal generating circuit.

[Action]

Therefore, the phases of the horizontal and vertical sync signals and the color burst in the composite video signal are constantly monitored, and when a discontinuous state occurs, they are immediately detected and the superposition of signals of different media is prohibited.

〔Example〕

 Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a circuit configuration of an embodiment of a character multiplex inserter device of the present invention.

In this embodiment, a circuit including a window-comparator 14 is added to the synchronous discontinuity detecting circuit 106 of the conventional character multiplex inserter device shown in FIG. 2, and a clock generating circuit 10 and a key having a corresponding function are provided. The signal generation circuit 5 is installed.

The clock generation circuit 10 reproduces the color subcarrier signal by the BCO circuit, detects the phase of the input color burst and the phase of the reproduced continuous color subcarrier signal with the phase detector, and The phase difference is output as an error voltage. The window-comparator 14 is composed of two comparators, each of which has a predetermined upper limit value and a predetermined lower limit value. When the error voltage is input from the clock generation circuit 10 and is out of the range of the upper limit value and the lower limit value. Output a detection signal. The key signal generation circuit 5 is the comparison circuit 1
When the detection signal of the window-comparator 14 is input in addition to the output of 5, the output of the key signal is stopped.

Therefore, the present embodiment monitors the horizontal and vertical sync signals and the color burst in the composite video signal 1, and when they are disturbed, prevents the superposition of the signals 2 of different media, and when the continuity is restored, normal It is possible to superimpose again at the timing of.

〔The invention's effect〕

As described above, according to the present invention, by adding the color sub-carrier phase error detecting means to the sync discontinuity detecting circuit and constantly monitoring the phases of the horizontal and vertical sync signals and the color burst, the error of these signals is detected. There is an effect that it is possible to detect the occurrence of continuity and prevent the superposition of signals of different media.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of an embodiment of a character multiplex inserter device of the present invention, and FIG. 2 is a block diagram showing a circuit configuration of a conventional example of a character multiplex inserter device. 1, 3 ... Composite video signal, 2 ... Heterogeneous media signal, 4 ... Gain control circuit, 5 ... Key signal generation circuit, 6 ... Sync discontinuity detection circuit, 7 ... Sync signal separation circuit, 8 ... 1H delay circuit, 9, 15 ... comparison circuit, 10 ... clock generation circuit, 11 ... pulse generation circuit, 12 ... address counter, 13 ... storage circuit, 14 ... window-comparator.

Claims (1)

[Claims] 1. A composite image in which a composite video signal of a television program and a signal of a heterogeneous medium are input to a gain control circuit, and the input signal of a heterogeneous medium is input according to a key signal output by a key signal generating circuit. A character that superimposes on a predetermined position of a signal and outputs, and when the sync discontinuity detection circuit detects discontinuity of the sync signal in the composite video signal, the key signal is stopped to prevent superposition of signals of different media. In the multiple inserter device, provided in the synchronous discontinuity detection circuit, detects the phase of the color subcarrier signal reproduced from the color burst in the input composite video signal, and detects the phase error when the phase error is out of the set range. And a color subcarrier phase error detecting means for outputting the color subcarrier phase error detecting means for outputting the color subcarrier phase error detecting means Teletext inserter characterized by having a key signal generating circuit to prevent superposition of media signals.