JPH03157069A - Synchronizing device - Google Patents

Abstract

PURPOSE:To eliminate the need for the phase adjustment operation by detecting a phase difference of a horizontal synchronizing signal separated by a 2nd separate circuit and a horizontal synchronizing signal included in a video signal inputted from a video camera via a coaxial cable and outputting a horizontal synchronizing signal with a phase corresponding to the phase difference to the video camera for synchronization. CONSTITUTION:A synchronizing separator circuit 71 as a 1st separator circuit separates a horizontal synchronizing signal included in an inputted video signal. The separated horizontal synchronizing signal is inputted to a waveform shaping circuit 72, where the signal is subjected to waveform shaping, and the result is inputted to a comparator 73. On the other hand, a synchronizing separator circuit 54 as a 2nd separator circuit separates a horizontal synchronizing signal included in a synchronizing signal coming from an external synchronizing signal generating circuit 53 and outputs the result to a waveform shaping circuit 74. The waveform shaping circuit 74 applies waveform- shaping to the inputted horizontal synchronizing signal and outputs the result to the comparator 73. The comparator 73 compares the phases of the horizontal synchronizing signals inputted from the waveform shaping circuits 72, 74 to detect its phase error. The error signal is smoothed by a low pass filter 75 and outputted to a waveform shaping circuit 55.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a synchronization device for synchronizing video signals output from a plurality of video cameras.

(Prior Art) FIG. 2 is a block diagram showing the fI configuration of an example of a conventional synchronizer.

In the figure, video cameras 1 to 3 are connected to camera controllers 1 and roll units (CCU) 4 to 6 as synchronizing devices via coaxial cables 1a to 3a. 7 is a special effect implementation [(SHG), ccu4
The video signals input from the coaxial cables 4a to 6a are combined into one video signal and output to a television (TV) receiver 8.6 Now, the lengths of the coaxial cables 1a to 3a are respectively Assuming L1 to L3, the video output from each video camera 1 to 3 (No. 8 corresponds to these lengths, and the video output is about 0 per 100 m.
．． It is delayed at a rate of 5 μsec. Result 1 For example, if the video signal of video camera 3 is used as a reference, the phase (horizontal phase) of the video signals of video cameras 1 and 2 is the length (L□-L 3 ) or (L, -L,), respectively. It is delayed by a time t1 or t2 corresponding to the length.

Therefore, a horizontal synchronization signal and a vertical synchronization signal are supplied from the CCU 6 to the CCUs 4 and 5, and the CCUs 4 and 5 correct the delay time t1 or t using this synchronization signal as a reference.

Since each CCU 4 to 6 and SEG 7 are connected by coaxial cables 4a to 6a with length Lo, each CCU 4
The video signals output from 6 to 6 are input to SEG 7 in the same phase. 5EG7 combines three video signals into one video signal and outputs it to the television receiver 8.

FIG. 3 is a block diagram showing an example of the configuration of the video camera 1 and the CCU 4 (video camera 2 or 3 and the CCU 5
or 6 is similarly configured).

In the figure, 11 is an imager consisting of a photoelectric converter.
, which photoelectrically converts the light from the object and outputs it to the process matrix circuit 12. The process matrix circuit 12 generates a luminance signal Y, color difference signals (RY), and (B-Y), and outputs them to an encoder (IENc) 13. The output of the encoder 13 is outputted to the coaxial cable 1a via the buffer amplifier 14 and the resistor 29.

15 is a cancellation circuit that cancels the signal input from the buffer amplifier 14 and extracts the signal input from the coaxial cable 1a. The output of the canceling circuit 15 is input to a synchronization separation circuit 16, where the separated vertical synchronization jtJ1 signal is outputted to a counter 18, and the horizontal synchronization signal is outputted to a comparator 25 and a detector 27, respectively. Comparison Ia 25 compares the phase of the horizontal synchronization signal output from counter 18 and delayed by a predetermined time rIII2 by delay circuit 24 with the horizontal synchronization signal input from synchronization separation circuit 16, and passes the error signal through a low-pass filter ( 0 oscillator 1 which outputs to the oscillator (OSC) l 9 via LPF) 26
The signal generated by 9 is input to a counter 18.

The output of the counter 18 is supplied to the encoder 13.

The detector 27 detects the pulse width of the input signal, and outputs the detection result to the oscillator (OSC) 21 via the low-pass filter (LPF) 28.The outputs of the six oscillators 21 are each shifted by 0° or 90'. It is supplied to the encoder 13 via phasers 22 and 23. Flip-flop (F F
) 20 controls the counter 18 and the phase shifter 22.

Counter 18, oscillators 19, 21 . flip flop 2
0 and phase shifters 22 and 23 constitute the SSG circuit 17.

The above is the configuration of the video camera 1.

Next, the configuration of CCu 4 will be described.

Reference numeral 51 denotes a canceling circuit that cancels the synchronizing signal outputted from the OR gate 60 to the coaxial cable 1a via the resistor 61, and outputs the video signal inputted from the coaxial cable 1a. The output of the cancellation circuit 51 is SEG 7
and is also supplied to the comparator 58.

The comparator 58 compares the phase of the color burst signal included in the signal input from the cancellation circuit 51 and the signal input from the external synchronization signal generation (VBS) circuit 53 (CC06 in the example of FIG. 2), The error signal is output to a modulator 57 via a low pass filter (LPF) 59.

The synchronization separation circuit 54 separates a horizontal synchronization signal and a vertical synchronization signal from the signal input from the external synchronization signal generation circuit 53, and outputs the horizontal synchronization signal to the waveform shaping circuit 55 and the vertical synchronization signal to the OR gate 60, respectively. ing. Waveform shaping circuit 5
5 shapes the horizontal synchronization signal input from the synchronization separation circuit 54 in response to the signal input from the manual horizontal phase adjuster 56 so as to adjust its phase (delay amount), and outputs it to the modulator 57. do. The horizontal synchronization signal outputted from the modulator 57 is combined with the vertical synchronization signal outputted from the synchronization separation circuit 54 by an OR gate 60, and outputted to the coaxial cable 1a via a resistor 61.

Next, its operation will be explained.

Light from the subject inputted into the imager 11 is photoelectrically converted and inputted into the process matrix circuit 12.

The process matrix circuit 12 generates a luminance signal Y, color difference signals (RY), (B-Y) from the input signals,
Output to encoder 13. The encoder 13 combines the color carrier signal (SC) and horizontal and vertical synchronization signals inputted from the SSG circuit 17 to form a composite signal. This composite video signal is transmitted to the buffer amplifier 14, the resistor 29. The signal is input to the cancellation circuit 51 of the CCU 4 via the coaxial cable 1a. The cancellation circuit 51 outputs the input video signal to 5EG7.

The synchronization separation circuit 54 separates the horizontal synchronization signal from the synchronization signal output by the external synchronization signal generation circuit 53, and converts the horizontal synchronization signal into the waveform shaping circuit 5.
Output to 5. The waveform shaping circuit 55 shapes the waveform of the input horizontal synchronizing signal and outputs it. At this time, the phase of the horizontal synchronization signal is adjusted to a set value by the manual horizontal phase adjuster 56.

On the other hand, a part of the video signal output from the cancellation circuit 51 is input to the comparator 58. The comparator 58 compares the phases of the color carrier wave signal output from the external synchronization signal generation circuit 53 and the color carrier wave signal included in the video signal output from the cancellation circuit 51, and outputs an error signal thereof. This error signal is smoothed by a low-pass filter 59 and modulator 57
is input. The modulator 57 modulates the pulse width of the horizontal synchronizing signal inputted from the waveform shaping circuit 55 and adjusted to a predetermined phase to a value corresponding to the output of the low-pass filter 59.

The horizontal synchronization signal output from the modulator 57 is combined with the vertical synchronization signal output from the synchronization separation circuit 54 at an OR gate 60, and output via a resistor 61 to the coaxial cable 1a.

Since the canceling circuit 51 operates to cancel this composite synchronizing signal, this composite synchronizing signal does not appear at the output of the canceling circuit 51.

The composite synchronization signal input via the coaxial cable 1a is input to the cancellation circuit 15. The cancellation circuit 15 cancels the video signal inputted from the buffer amplifier 14, passes only the composite synchronization signal inputted from the coaxial cable 1a, and outputs it to the synchronization separation circuit 16. The synchronization separation circuit 16 separates a vertical synchronization signal and a horizontal synchronization signal from the input signal.

The counter 18 counts the pulses of a predetermined frequency output by the oscillator 19, and outputs the pulses at the timing of the horizontal scanning period. This pulse is delayed by 2τ by the delay circuit 24 and output to the comparator 25.

Here, the delay time τ due to the coaxial cable 1a. Among them, this corresponds to the longest time (the maximum length of the coaxial cable 1a) within the correctable range. Video camera 1
Since the video signal is transmitted from the side to the CCU 4 via the coaxial cable 1a, and the synchronization signal synthesized in the CCU 4 is transmitted to the video camera 1 via the coaxial cable 1a, the delay due to the simultaneous cable 1a is at most 2τ.
becomes. Therefore, the delay time by the delay circuit 24 is set to 2τ.

The comparator 25 detects the phase difference between the horizontal synchronization signal No. 48 corresponding to the horizontal synchronization signal input from the delay circuit 24 and the horizontal synchronization signal input from the synchronization separation circuit 16, and outputs the error signal from the 0 oscillator 19. The pulse frequency fll is controlled in response to this error signal.

The horizontal synchronization signal output from the synchronization separation circuit 16 is 2τ due to the coaxial cable 1a compared to the horizontal synchronization signal output from the video camera 1 to the coaxial cable 1a. , are delayed by t by the waveform shaping circuit 55. Therefore, at 2τ−2. The delay Jt by the manual horizontal phase adjuster 56 so that = J
By adjusting t and □, the horizontal phase is set to the amount of delay corresponding to the case where the coaxial cable 1a is at its maximum length.

The counter 18 resets its count value every time a vertical synchronization signal is input from the synchronization separation circuit 16. Then, a horizontal synchronization signal and a vertical synchronization signal are output to the encoder 13 in accordance with the count value.

On the other hand, the detector 27 detects the pulse width of the horizontal synchronization signal output from the synchronization separation circuit 16. This detection signal is supplied to the oscillator 21 via the low-pass filter 28, and its oscillation frequency fsc is controlled.

The pulse width detected by the detector 27 corresponds to the phase difference between the reference color carrier signal and the color' carrier signal output from the video camera 1, as described above. Therefore, servo is applied so that the phase difference becomes zero.

The output of the oscillator 21 is outputted to the encoder 13 via phase shifters 22 and 23 with its phase shifted by 0'' (as is) or by 90°.The encoder 13 outputs signals of one phase and the other phase for each IH. are alternately selected and combined with the signal from the process matrix circuit 12.

[Problem to be solved by the invention]

Conventional synchronizers thus include a manual horizontal phase adjuster 56.
By manually operating the coaxial cables 1a to 3a,
I tried to compensate for the delay due to this. Generally, after the connection using the coaxial cables 1a to 3a is completed, the exact length becomes unknown because it is not particularly memorized.

Additionally, the length of the coaxial cable may be changed. In such cases, use manual horizontal phase adjustment! 1ft56 requires fine adjustment, but this adjustment not only requires an oscilloscope, but also has the disadvantage that it takes time.

The present invention was made in view of this situation, and eliminates the need for adjustment.

[Means to solve the problem]

The synchronization device of the present invention is a synchronization device that synchronizes a video camera connected via a coaxial cable with another video camera, and includes a first separation device that separates a horizontal synchronization signal from a video signal input via the coaxial cable. circuit, and a second circuit that separates the horizontal synchronization signal and vertical synchronization signal from the external synchronization signal.
with separation circuit.

a comparator that compares the phases of the horizontal synchronization signals separated by the first separation circuit and the second separation circuit; and a horizontal synchronization signal separated by the second separation circuit in response to the error signal outputted by the comparator. It includes an adjustment circuit that adjusts the phase of a signal, and an output circuit that outputs a horizontal synchronization signal whose phase has been adjusted by the adjustment circuit and a vertical synchronization signal separated by a second synchronization separation circuit to a coaxial cable.

[Effect]

In the synchronization device configured as described above, the phase difference between the horizontal synchronization signal in the video signal output from the video camera and the reference horizontal synchronization signal is detected, and the signal is output to the video camera for synchronization in accordance with the phase difference. The amount of delay of the horizontal synchronization signal is automatically controlled.

Therefore, no adjustment is required.

〔Example〕

FIG. 1 is a block diagram showing the configuration of an embodiment of the synchronization device of the present invention, and parts corresponding to those in FIGS. 2 and 3 are given the same reference numerals.

In FIG. 1, reference numeral 71 denotes a synchronization separation circuit, which separates a horizontal synchronization signal from the output of the cancellation circuit 51 and outputs it to the waveform shaping circuit 72. A comparator 73 compares the output of the waveform shaping circuit 72 with a signal obtained by waveform shaping the horizontal synchronization signal output from the synchronization separation circuit 54 by the waveform shaping circuit 74, and outputs an error signal. This error signal is supplied to the waveform shaping circuit 55 via a low pass filter (LPF) 75.

These circuits are the manual horizontal phase adjuster 56 in the third @.
is provided in place of.

The other configurations are the same as in FIG. 3.

Next, its operation will be explained.

As in the case described above, the video signal output from the video camera 1 is input to the cancellation circuit 51 of the CCIJ4 via the coaxial cable 1a, and output to the 5EG7.

A part of the video signal output from the cancellation circuit 51 is input to the synchronization separation circuit 71. A synchronization separation circuit 71 serving as a first separation circuit separates a horizontal synchronization signal included in an input video signal.The horizontal synchronization signal separated by 0 is input to a waveform shaping circuit 72, and after being waveform-shaped, 73. On the other hand, the synchronization separation circuit 54 as a second separation circuit separates the horizontal synchronization signal from the synchronization signal input from the external synchronization signal generation port M53, and
It is output to 4. The waveform shaping circuit 74 shapes the waveform of the input horizontal synchronizing signal and outputs it to the comparator 73. The comparator 73 compares the phases of the horizontal synchronizing signals input from the waveform shaping circuit 72 and the waveform shaping circuit 74, and detects the phase error.

This error signal is smoothed by a low-pass filter 75,
The signal is output to the waveform shaping circuit 55.

The waveform shaping circuit 55 as an adjustment circuit is a synchronization separation circuit 5
The phase of the reference horizontal synchronization signal separated by 4 is
The waveform is shaped to correspond to the error signal input from the comparator 73 via the low-pass filter 75.

In this way, the waveform shaping circuit 55 outputs a horizontal synchronization signal having a phase corresponding to the phase difference between the reference horizontal synchronization signal and the horizontal synchronization signal in the video signal output to the SHG 7.

A comparator 58 generates a phase error signal between the reference color carrier signal output from the external synchronization signal generation circuit 53 and the color carrier signal in the video signal supplied to the SEG 7. The modulator 57 modulates the pulse width of the horizontal synchronizing signal output from the waveform shaping circuit 55 in response to this error signal.

The horizontal synchronization signal generated in this way is combined with the reference vertical synchronization signal output from the synchronization separation circuit 54 in an OR gate 60 serving as an output circuit, and transmitted to the video camera 1 side via a resistor 61 and coaxial cable 1a. be done.

Therefore, operations similar to those described above are performed. The operation is the same as that described above, so a description thereof will be omitted.

〔Effect of the invention〕

As described above, according to the synchronization device of the present invention, the horizontal synchronization signal separated by the second separation circuit and the horizontal synchronization signal included in video No. 48 input from the video camera via the coaxial cable are separated. Since the phase difference is detected and the horizontal synchronization signal of the phase corresponding to this phase difference is output to the video camera for synchronization, one phase adjustment operation is not required regardless of the length of the coaxial cable.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the synchronization device of the present invention, FIG. 2 is a block diagram showing the basic configuration of a conventional example for synchronizing multiple video cameras, and FIG. FIG. 1 is a block diagram showing the configuration of an example of a conventional synchronization device. 1.2.3...TV camera, 1a to 3a, 4a to 6a...coaxial cable, 4 to 6...camera control unit (CCU), 7...special effects device (
SEG), 8... Television receiver, 13... Encoder, 15.51... Cancellation circuit, 16,5
4.71... Synchronization separation circuit, 22.23... Phase shifter, 25,58.73... Comparator, 53... External synchronization signal generation circuit (is), 55.72.74... ...Waveform shaping circuit, 60...OR gate.

Claims (1)

[Claims] A synchronization device for synchronizing a video camera connected via a coaxial cable with another video camera, comprising: a first separation for separating a horizontal synchronization signal from a video signal input via the coaxial cable; a second separation circuit that separates a horizontal synchronization signal and a vertical synchronization signal from an external synchronization signal; and a comparator that compares the phases of the horizontal synchronization signals separated by the first separation circuit and the second separation circuit. and an adjustment circuit that adjusts the phase of the horizontal synchronization signal separated by the second separation circuit in response to the error signal output by the comparator; and a horizontal synchronization signal whose phase is adjusted by the adjustment circuit. and an output circuit that outputs the vertical synchronization signal separated by the second synchronization separation circuit to the coaxial cable.