JP3104229B2 - External synchronization device for video camera - Google Patents

Description

The present invention relates to an external synchronization device for a video camera that outputs a video signal synchronized with an external synchronization signal.

B. Summary of the Invention The present invention is an external synchronizing device for a video camera which is supplied with an external synchronizing signal including a color synchronizing signal and outputs a video signal in synchronization with the external synchronizing signal, wherein the oscillation phase is variably controllable. The phase of the continuous color subcarrier generated by the color chrominance subcarrier generation means and the phase of the color synchronization signal separated from the external synchronization signal by the first burst separation means are compared by the first phase comparison means. By controlling the oscillation phase of the chrominance subcarrier generation means at the output, a continuous chrominance subcarrier is generated by the chrominance subcarrier generation means in synchronization with the external synchronization signal, and the color from the chrominance subcarrier generation means is controlled. The color synchronization signal included in the output video signal generated by the video signal generation means using the subcarrier is separated by the second burst separation means, and the color subcarrier delayed by the delay circuit is separated. The phase and the second burst separation means by the output video signal of the separated color burst signal from the phase second
The first phase comparing means controls the amount of delay given by the delay means to the color subcarrier to be phase-compared to the color synchronization signal by the first phase comparing means by the comparison output of the second phase comparing means. Thus, an output video signal having a color synchronization signal whose phase matches that of the chromaticity synchronization signal of the external synchronization signal is output from the video signal generation means.

C. Prior Art For example, in a live broadcast of a baseball game, a plurality of video cameras are used, and for example, as shown in FIG.
Each of the video signals output from the 03 (hereinafter referred to as the output video signal) is a so-called switcher 104 provided in the center
To switch to broadcast. By the way, when the plurality of video cameras 101 to 103 are used as described above, if the output video signals from the video cameras 101 to 103 are not synchronized, the monitor receiver 105 switches the synchronization for a moment every time the switcher 104 is switched. It will be off, and the colors will look slightly different for each of the video cameras 101-103.

Therefore, normally, a synchronization signal (hereinafter, referred to as an external synchronization signal) is externally supplied to each of the video cameras 101 to 103, and each output video signal is synchronized with the external synchronization signal. The phase of the color synchronization signal of the signal is adjusted.

Here, a conventional external synchronizer for a video camera will be described. FIG. 3 is a block circuit diagram of a conventional external synchronizer for a video camera.

An external synchronization signal is input to the terminal 70 from, for example, a switcher 104 shown in FIG. 2, and the external synchronization signal is supplied to a synchronization signal separation circuit 71 and a burst separation circuit 78. The external synchronization signal is a signal including various synchronization signals such as a so-called horizontal synchronization signal and a color synchronization signal. Sync signal separation circuit 71
Separates the horizontal synchronizing signal from the external synchronizing signal, and supplies the separated horizontal synchronizing signal to a phase lock loop (hereinafter, referred to as a PLL) including the phase comparator 72 to the phase adjusting circuit 76. This PLL uses a phase of a horizontal synchronization signal separated from an external synchronization signal and a voltage-controlled oscillator (hereinafter, referred to as a PLL).
A signal having a frequency which is 910 times the frequency of the horizontal synchronizing signal generated by the VCO 74 is divided by the frequency divider 75, and the phase of the signal obtained through the phase adjustment circuit 76 is compared by the phase comparator 72. The oscillation phase of the VCO 74 is controlled so that the phase difference becomes zero. The output of the VCO 74 is used to form horizontal synchronization, vertical synchronization, and the like of the output video signal. The phase adjustment circuit 76 is for adjusting the shift of the horizontal synchronizing signal between the output video signals caused by the difference in the length of each cable connecting the video cameras 101 to 103 and the switcher 104.

On the other hand, the burst separation circuit 78 separates a color synchronization signal (a so-called burst signal) included in the external synchronization signal, and comprises the separated burst-like color synchronization signal by a phase comparator 80 to a phase adjustment circuit 85. Supply to the PLL. This PLL is
The phase of the color sync signal separated from the external sync signal and VCO8
A signal having a frequency four times the frequency of the chrominance subcarrier generated in 2 is divided by a frequency divider 83, and the phase of the signal obtained through a phase adjustment circuit 85 is compared by a phase comparator 80. The oscillation phase of the VCO 82 is controlled so that the phase difference becomes zero. That is, the burst separation circuit 78 to the phase adjustment circuit 85 constitute a so-called burst control oscillation circuit. The phase adjustment circuit 85 includes the video cameras 105 to 103 and the switcher 10.
This is for adjusting the phase shift of the color synchronizing signal between the video signals caused by the difference in the length of each cable connecting each of the four.

The phase circuit 91 uses the chrominance subcarrier from the frequency divider 83,
A color subcarrier that is 90 degrees out of phase with the color subcarrier is generated.
These two color subcarriers having phases different from each other by 90 degrees are respectively supplied to a balanced modulation circuit 92 for performing quadrature quadrature modulation. The balanced modulation circuit 92 uses the two signals obtained by combining the so-called color difference signals inputted via the terminals 7 and 8 at a predetermined ratio to separate the two color subcarriers having phases different from each other by 90 degrees from each other in amplitude. Modulation to generate a so-called carrier color signal. That is, for example, in the case of the NTSC system, the so-called I signal and Q signal are used, and in the case of the PAL system and the SECAM system, the so-called U signal and V signal are used.
Amplitude modulation is performed on the two color subcarriers having different phase degrees to generate a carrier chrominance signal.

A band pass filter (hereinafter, referred to as BPF) 93 suppresses the carrier of the carrier chrominance signal from the balanced modulation circuit 92 and sends it to an addition circuit (so-called Y / C mix circuit) 96 via an amplifier (so-called chroma amplifier) 94. . The adder 96 adds a luminance signal (hereinafter, referred to as a Y signal) including a synchronization signal such as a horizontal period signal input via the terminal 9 and the carrier chrominance signal to generate an output video signal. , 75Ω line driver 97
And the output video signal via terminal 99
It is sent to the switcher 104 shown in the figure.

If the lengths of the cables connecting the video cameras 101 to 103 and the switcher 104 shown in FIG.
The horizontal synchronization of each video signal at the input point 4 is performed, and the phases of the color synchronization signals are matched. That is, by adjusting the volume 76a of each of the phase adjustment circuits 76 of the video cameras 101 to 103, horizontal synchronization of each video signal from the video cameras 101 to 103 is obtained, and the volume 85a of each of the phase adjustment circuits 85 is adjusted. The phases of the color synchronizing signals of the respective video signals are aligned to prevent the instantaneous loss of synchronization caused by the switching of the switcher 104 as described above and the occurrence of a subtle color difference between the video cameras 101 to 103. ing.

D. Problems to be Solved by the Invention By the way, if the signal delay amount in the phase shift circuit 91 to the line driver 97 fluctuates due to temperature or the like, once the switcher
The phase of the horizontal synchronization and color synchronization signals adjusted at the input point 4 are shifted between the video signals, and each time the switcher 104 is switched, a subtle color difference occurs between the cameras, and the synchronization is lost for a moment. become. Therefore, conventionally, the components used for the phase shift circuit 91 to the line driver 97 have a small temperature deviation and are expensive.

As shown in FIG. 4, both the color synchronization signal separated from the external synchronization signal and the color synchronization signal separated from the output video signal are burst signals, and the horizontal synchronization between the external synchronization signal and the output video signal is When the synchronization is out of sync, the phases of these color synchronization signals could not be directly compared.

The present invention has been made in view of such circumstances, and even when the horizontal synchronization signal between the horizontal synchronization signal and the output video signal is shifted, the color synchronization signal separated from the external synchronization signal and The phase of the color synchronization signal separated from the output video signal can be equivalently compared, and the output video signal is inexpensive and always synchronized with the external synchronization signal without being affected by ambient environmental conditions such as temperature. It is an object of the present invention to provide an external synchronizing device for a video camera capable of performing the following.

E. Means for Solving the Problems An external synchronization device for a video camera according to the present invention is supplied with an external synchronization signal including a color synchronization signal, and outputs a video signal in synchronization with the external synchronization signal. A synchronizing device, a first burst separating means for separating a color synchronizing signal included in the external synchronizing signal, a color subcarrier generating means capable of variably controlling an oscillation phase for generating a continuous color subcarrier, The phase of the continuous color subcarrier generated by the color subcarrier generating means is compared with the phase of the color synchronizing signal separated from the external synchronizing signal by the first burst separating means. First phase comparing means for controlling the oscillation phase of the carrier generating means to generate a color subcarrier synchronized with the color synchronization signal by the color subcarrier generating means; A variably controllable delay means for delaying the chrominance subcarrier to be phase-compared with the chrominance synchronization signal, and a video signal for generating an output video signal using the chrominance subcarrier from the chrominance subcarrier generation means Generating means, second burst separating means for separating a color synchronization signal included in an output video signal from the video signal generating means, phase of the color subcarrier delayed by the delay circuit, and second burst separating Means for comparing the phase of the color synchronization signal separated from the output video signal by the means, and controlling the amount of delay of the delay means based on the comparison output; An output video signal having a color synchronization signal whose phase matches the synchronization signal is output from the video signal generation means.

F. Function In the external synchronizer for a video camera according to the present invention, the phase of the continuous chrominance subcarrier generated by the chromatic subcarrier generation means whose oscillation phase is variably controllable and the first burst separation means are used to separate the phase from the external synchronization signal. The phase of the separated color synchronizing signal is compared by the first phase comparing means, and the oscillating phase of the color subcarrier generating means is controlled by the comparison output, so that the continuous color subcarrier is synchronized with the external synchronizing signal. Is generated by the color subcarrier generation means. The color synchronizing signal contained in the output video signal generated by the video signal generating means is separated by the second burst separating means by using the color subcarrier from the color subcarrier generating means, and is delayed by the delay circuit. The phase of the chrominance subcarrier thus obtained and the phase of the color synchronization signal separated from the output video signal by the second burst separation means are compared by the second phase comparison means, and the color synchronization is performed by the first phase comparison means. By controlling the amount of delay given by the delay means to the chrominance subcarrier to be phase-compared with the signal by the comparison output of the second phase comparison means, the color synchronization having the same phase as the chromaticity synchronization signal of the external synchronization signal is obtained. An output video signal having a signal is output from the video signal generation means.

G. Embodiment Hereinafter, an embodiment of the external synchronizer for a video camera according to the present invention will be described with reference to the drawings. FIG. 1 is a block circuit diagram showing a configuration of an external synchronizer for a video camera according to the present invention.

In this external synchronization device for a video camera, a terminal 10 is connected to an external synchronization signal including various synchronization signals such as a horizontal synchronization signal and a color synchronization signal from a switcher 104 shown in FIG. 2, for example, an external synchronization signal including a video signal. EXT VBS or an external synchronization signal BS not including a video signal is input.

This video camera external synchronizing device includes a horizontal synchronizing signal generation circuit that generates a horizontal synchronizing signal from the external synchronizing signal, which is composed of a synchronizing signal separating circuit 11 to a phase adjusting circuit 16, and a burst separating circuit 18 to a dividing period 23. A color subcarrier generation circuit for generating a color subcarrier from the external synchronization signal, and an output video signal generation for generating an output video signal using the color subcarrier composed of a phase shift circuit 31 to a line driver 37 And a phase control circuit including a burst separation circuit 38, a phase comparator 27, and a delay circuit 24.

The horizontal synchronizing signal generation circuit is synchronized with the horizontal synchronizing signal separated from the external synchronizing signal and the synchronizing signal separating circuit 11 for separating the horizontal synchronizing signal from the external synchronizing signal input through the terminal 10. Phase comparator 12 for generating horizontal synchronization signal, LPF 13, VCO 14, frequency divider 15 for dividing 1/910
And a kind of PLL constituted by the phase adjustment circuit 16. The phase adjustment circuit 16 is, for example, a second
This is for adjusting the shift of the horizontal synchronizing signal between the output video signals caused by the difference in the length of each cable connecting the video cameras 101 to 103 and the switcher 104 shown in the figure.

The color sub-carrier generation circuit includes a burst separation circuit 18 for separating a burst-like color synchronization signal from an external synchronization signal input through the terminal 50, and the burst separation circuit 18
Phase comparator 20, LPF21, VCO22, which generates a continuous color subcarrier in synchronization with the burst-like color synchronization signal separated by
A type of PLL including a frequency divider 23 that performs 1/4 frequency division, a delay circuit 24, and the phase adjustment circuit 25 is provided. That is, in this embodiment, the burst separation circuit 18 is used as first burst separation means for separating the color synchronization signal included in the external synchronization signal, and the oscillation phase for generating a continuous color subcarrier can be variably controlled. The color subcarrier generation means
The VCO 22 and the frequency divider 23, the phase of the continuous color subcarrier generated by the color subcarrier generation means and the phase of the color synchronization signal separated from the external synchronization signal by the first burst separation means And controlling the oscillation phase of the chrominance sub-carrier generation means by the comparison output,
The phase comparator 20 is used as first phase comparison means for generating a color subcarrier synchronized with the color synchronization signal by the color subcarrier generation means, and further, the color synchronization signal is generated by the first phase comparison means. The delay circuit 24 is used as delay means capable of variably controlling the amount of delay for delaying the chrominance subcarrier which is compared with the phase. The phase adjustment circuit 25 includes the video cameras 101 to 103 and the switcher.
This is for adjusting the phase shift of the color synchronizing signal between the video signals caused by the difference in the length of each cable connecting the respective 104 and 104.

The output video signal generation circuit is input via terminals 1 and 2 to a phase shift circuit 31 that generates a color subcarrier having a phase difference of 90 degrees using the color subcarrier from the frequency divider 23. For example, using an I signal and a Q signal obtained by combining a predetermined ratio of color difference signals of the NTSC system, or using PAL
Modulation circuit that generates a carrier chrominance signal by amplitude-modulating the two color sub-carriers having phases different from each other by 90 degrees using a U signal and a V signal obtained by a combination of predetermined ratios of color difference signals of the CAM or SECAM system. 32, BPF 33 and amplifier 34
An addition circuit 36 that adds the carrier chrominance signal supplied through the terminal and the Y signal including a synchronization signal such as a horizontal synchronization signal input through the terminal 3 to generate an output video signal;
And a line driver 37. That is, in this embodiment, the video signal generating means for generating the output video signal is composed of the phase shift circuit 31 to the line driver 37.

The phase control circuit includes: a burst separation circuit 38 for separating a burst-shaped color synchronization signal from an output video signal from the line driver 37; a phase of the color synchronization signal separated by the burst separation circuit 38; A phase comparator 27 for comparing the phase of the delayed color subcarrier from the circuit 24 and controlling the delay amount of the delay circuit 24 so that the phase difference becomes zero.

That is, in this embodiment, the burst separation circuit 38
Are used as second burst separating means for separating the color synchronization signal included in the output video signal, and are separated from the output video signal by the second burst separating means and the color subcarrier delayed by the delay means. The phase comparator 27 is used as second phase comparing means for comparing the phases of the obtained color synchronizing signals and controlling the delay amount of the delay means by the comparing means.

Next, the operation will be described. The synchronization signal separation circuit 11 is connected to the terminal 10
To separate the horizontal synchronizing signal from the external synchronizing signal input through the. Consists of a phase comparator 12 to a phase adjustment circuit 16
The PLL divides the phase of the horizontal synchronizing signal from the synchronizing signal separation circuit 11 and the signal generated by the VCO 54 by 1/1010 by the frequency divider 15 and obtains the phase of the signal obtained through the phase adjustment circuit 16. Are compared in the phase comparator 12, and the oscillation phase of the VCO 14 is controlled so that the phase difference becomes zero. The output of the VCO 14 is used to form horizontal synchronization, vertical synchronization, and the like of the output video signal.

The burst separation circuit 18 separates a burst-like color synchronization signal from the external synchronization signal. The PLL composed of the phase comparator 20 to the phase adjustment circuit 25 is connected to the phase of the color synchronization signal separated from the external synchronization signal by the burst separation circuit 18 and the VCO2
The signal generated in 2 is divided by a frequency divider 23 into a quarter, and the phase of the signal obtained through the delay circuit 24 and the phase adjustment circuit 25 is compared in the phase comparator 20. The oscillating phase of the VCO 22 is controlled such that is zero, and the color subcarrier is output from the frequency divider 23.

The phase shift circuit 31 uses the color subcarrier from the frequency divider 23,
Generate a color subcarrier having a 90 degree phase difference from the color subcarrier,
The color subcarriers having a phase difference of 90 degrees are sent to the balanced modulation circuit 32. The balanced modulation circuit 32 receives an NTSC I signal, a Q signal, or a PAL signal input through terminals 1 and 2, respectively.
A quadrature two-phase modulation is performed by using the U signal and the V signal of the SECAM system or the SECAM system to generate a carrier chrominance signal.

The BPF 33 suppresses the carrier of the carrier chrominance signal from the balanced modulation circuit 32. The addition circuit 36 generates an output video signal by adding the carrier chrominance signal and the Y signal including the synchronization signal input through the terminal 3, and outputs the output video signal through the line driver 37 and the terminal 39. , For example, to the switcher 104 shown in FIG.

The burst separation circuit 38 separates a burst-like color synchronization signal from the video signal output from the line driver 37 and supplies the color synchronization signal to the phase comparator 27. The phase comparator 27 compares the color synchronization signal with the phase of the color subcarrier delayed by the delay circuit 24,
The delay amount of the delay circuit 24 is controlled so that the phase difference becomes zero.

That is, a delay circuit such that the phase difference between the color synchronization signal separated from the output video signal from the burst separation circuit 38 and the delayed color subcarrier from the delay circuit 24 is always zero.
By controlling the delay amount of the delay circuit 24, the signal delay amount of the phase shift circuit 31 to the line driver 37 and the delay amount of the delay circuit 24 can always be the same. When the delay amount of the phase adjustment circuit 25 is set to zero, the color synchronization signal separated from the external synchronization signal from the burst separation circuit 18 and the phase adjustment circuit 25
By controlling the oscillation phase of the VCO 22 so that the phase difference between the output of the VCO 22 and the delayed color subcarrier from the delay circuit 24 is always zero, the color synchronization signal and the output video signal included in the external synchronization signal are controlled. The phase difference from the included color synchronization signal can be made zero. In other words, it is possible to obtain an output video signal having a color synchronization signal synchronized with the horizontal synchronization signal of the external synchronization signal and having the same phase as the color synchronization signal of the external synchronization signal. In addition, phase shift circuit depending on temperature etc.
Even if the signal delay amount of the line driver 37 changes, the color synchronization signal of the output video signal is controlled by controlling the delay amount of the delay circuit 24 in accordance with the signal delay amount. Can always be synchronized.

By the way, a video camera to which this embodiment is applied is
When used in the system shown in the figure, the horizontal synchronization of each video signal from the video cameras 101 to 103 can be achieved by adjusting the volume 16a of each of the phase adjustment circuits 16 of the video cameras 101 to 103. Video camera 10
By adjusting the volume 25a of each of the phase adjustment circuits 25 of 1 to 103, the phases of the color synchronization signals of the video signals from the video cameras 101 to 103 are matched, that is, the synchronization of the color synchronization signals of the video signals is synchronized. Can be taken.

H. Effects of the Invention As is clear from the above description, according to the present invention, the phase of the continuous color subcarrier generated by the color subcarrier generation means whose oscillation phase is variably controllable is controlled by the first burst separation means. Since the phase of the color synchronizing signal separated from the external synchronizing signal is compared by the first phase comparing means, the phase of the burst color synchronizing signal separated from the external synchronizing signal by the first burst separating means is changed to the color It can be compared with the phase of the continuous chrominance subcarrier generated by the subcarrier generation means, and by controlling the oscillation phase of the chrominance subcarrier generation means with the comparison output, it is possible to continuously synchronize with the external synchronization signal. The color subcarrier can be generated by the color subcarrier generator. Then, the phase of the continuous color subcarrier generated by the color subcarrier generating means and the second
The phase of the color synchronizing signal separated from the output video signal by the burst separating means is compared by the second phase comparing means, and the burst-shaped color synchronizing signal separated from the output video signal by the second burst separating means is compared. The phase can be compared with the phase of the color subcarrier delayed by the delay circuit,
By controlling the amount of delay given by the delay means to the color subcarrier to be phase-compared with the color synchronization signal by the first phase comparison means by the comparison output of the second phase comparison means, An output video signal having a color synchronization signal whose phase matches the chromaticity synchronization signal is output from the video signal generation means.

As described above, according to the present invention, the synchronous control of the output video signal is performed by using the comparison output by the first and second phase comparing means, thereby being inexpensive and influenced by the surrounding environment such as temperature. In addition, it is possible to provide an external synchronizer for a video camera capable of transmitting an output video signal constantly synchronized with an external synchronization signal.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram of an external synchronizer for a video camera according to the present invention, FIG. 2 is a block diagram of a broadcasting system using a plurality of video cameras, and FIG. 3 is a conventional external synchronizer for a video camera. FIG. 9 is a block circuit diagram of a synchronization device,
The figure is a waveform diagram showing a relationship between an external synchronization signal and an output video signal. 18, 38 Burst separation circuit 20, 27 Phase comparator 22 Voltage controlled oscillator 24 Delay circuit 25 Phase adjustment circuit 32 Balanced modulation circuit 33 Bandpass filter 34 Amplifier 36 ... Addition circuit 37 ... 75Ω line driver

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 9/44 H04N 5/232 H04N 9/455

Claims (1)

(57) [Claims] 1. An external synchronizing device for a video camera to which an external synchronizing signal including a color synchronizing signal is supplied and which outputs a video signal in synchronization with the external synchronizing signal, wherein the color synchronizing signal included in the external synchronizing signal First to separate
Burst separating means, a color subcarrier generating means capable of variably controlling an oscillation phase for generating a continuous color subcarrier, and a phase of the continuous color subcarrier generated by the color subcarrier generating means and the first The phase of the color synchronizing signal separated from the external synchronizing signal by the burst separating means is compared, and the oscillation output of the color subcarrier generating means is controlled by the comparison output, so that the color subcarrier synchronized with the color synchronizing signal is output. First phase comparing means for generating the color subcarrier by the chrominance subcarrier generating means, and a variable controllable delay of a delay amount for delaying the color subcarrier to be phase-compared with the color synchronization signal by the first phase comparing means. Means, a video signal generating means for generating an output video signal using the color subcarrier from the color subcarrier generating means, A second burst separation means for separating a color burst signal, the delayed color subcarrier with said delay means the phase and the second
Second phase comparing means for comparing the phase of the color synchronizing signal separated from the output video signal by the burst separating means, and controlling the delay amount of the delay means based on the comparison output; An external synchronizer for a video camera, wherein an output video signal having a color synchronization signal whose phase matches the chromaticity synchronization signal is output from the video signal generation means.