JPS63266686A - Synchronizing device - Google Patents

Abstract

PURPOSE:To prevent the slip of a sampling frequency by generating and outputting a second video synchronizing signal, which synchronizes with a first video synchronizing signal and has a different frame frequency, and a second time code, which synchronizes with this signal and coincides with a first time code at a real time, from the first video synchronizing signal and the first time code synchronizing with this. CONSTITUTION:A first means generates a frame synchronizing pulse P1 having the same frequency as the frame frequency of the second video synchronizing signal, from the first video synchronizing signal S1, and generates and outputs the second video synchronizing signal S2 based on the said frame synchronizing pulse P1. Accordingly, the second video synchronizing signal S2, generated and outputted in/from the first means, has the different frame frequency, but synchronizes with the first video synchronizing signal S1. A second means, responding to the frame synchronizing pulse P1, generates and outputs the second time code TC2 from the first time code TC1. Thus, the second time code TC2, generated and outputted in/from the second means, synchronizes with the second video synchronizing signal S2, and coincides with the first time code TC1 at the real time, and prevents the sampling frequency from slipping out from a regular frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a synchronization device, and particularly to a synchronization device that synchronizes with a first video synchronization signal from a first video synchronization signal and a first time code synchronized therewith. The present invention relates to a synchronization device that generates and outputs a second video synchronization signal having a different frame frequency and a second time code that is synchronized with the second video synchronization signal and coincides with the first time code in real time.

Conventional technical magnetic tape video signal recording and reproducing equipment for commercial use uses the well-known SMPTE (5oci) standard.
ety of Motion p 1cture an
dT elevision engineering) A time code is recorded and reproduced together with the video signal. In the 24-hour SMPTE time code, N T S C
In the case of color synchronization in the color television system, the number of frames is 29.97 frames per second, so the S
MPTE time code increments occur, albeit slightly. Therefore, the SMPTE time code advances with respect to real time at 108 frames (3.6 seconds) per hour, which poses a problem in long-term measurements. Therefore, in order to correct the discrepancy between color synchronization and real time, a drop frame mode is generally used in which a predetermined frame number is skipped.

By using the drop frame mode, the deviation between color synchronization and real time can be corrected to a virtually non-problematic degree. S in drop frame mode like this
MPTE time code is for professional digital audio.
Also used in the system.

On the other hand, digital audio systems that use consumer magnetic tape video signal recording and reproducing devices to record and reproduce digital audio signals instead of video signals have come into widespread use in recent years. In a digital audio system, an analog audio signal is subjected to PCM (pulse code modulation), for example, and the PCM audio signal is recorded and reproduced in the form of a pseudo video signal. An example of a consumer PCM encoder/decoder is E.
lAJ (Electronic Industries Association of Japan) standard CP Z-10
5, etc., and in the case of a digital audio system that adopts a 60 field 525 line power type standard, N
The frame frequency of the Ding SC color television system is 29
．． When synchronized with the color video signal which is 97H7, the sampling frequency of the digital (PCM) audio signal is 44.05.
6 kHz is well known.

Problems to be Solved by the Invention However, the sampling frequency of an analog audio signal in a professional digital audio system (a professional PCM encoder/decoder) is determined to be 44.1 kLlz. Therefore, when applying the same II to a professional digital audio system using the video synchronization signal of the NTSC color television system, the sampling frequency becomes 44.056 kHz.
This results in a deviation from the standard 44.1 kHz. Therefore, there is a problem in that the digital audio signal from the professional digital audio system cannot be used as a digital audio mask for the color video signal of the NTSC color television system.

In this specification, a digital audio mask refers to a digital audio signal source (for example, a digital audio system consisting of a PCM encoder and decoder) that is a signal source of a digital audio signal for a standard television color video signal. means.

Therefore, the present invention provides a second video synchronization signal that is synchronized with the first video direction II signal and has a different frame frequency from a first video synchronization signal and a first time code that is synchronized therewith. The purpose of the present invention is to provide a synchronization device that solves the above problems by generating and outputting a second time code that is synchronized with a video synchronization signal and coincides with the first time code in real time. do.

Means for Solving the Problems The W4 device of the present invention includes first means for generating and outputting a second video synchronization signal which is synchronized with the first video synchronization signal and has a different frame frequency. , the first Il! A second means for generating and outputting a second time code that is synchronized with the second video synchronization signal and matches the first time code in real time from a first time code that is synchronized with the circular image signal. It becomes more.

The first operation means generates a frame synchronization pulse having the same frequency as the frame frequency of the second video synchronization signal from the first video synchronization signal, and generates a second frame synchronization pulse based on this frame frequency +1 pulse.
Generates and outputs a video synchronization signal. Therefore, the second video synchronization signal generated and outputted by the first means is synchronized with the first video synchronization signal, although the frame frequency is different.

A second means responsive to the frame synchronization pulse
A second time code is generated and output from the time code. As a result, the second time code generated and output by the second means is synchronized with the second video synchronization signal and matches the first time code in real time.

Example An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block system diagram showing one embodiment of the device of the present invention.
) is applied and supplied to the frame extraction circuit 2.The frame extraction circuit 2 receives the second video synchronization signal obtained by frame extraction from the first video synchronization signal S1. A frame synchronization pulse P1 with a frequency f1 (not shown in Figure (B)) is supplied to the phase comparator 3. In this embodiment, f+ = 29.97kHz2. The oscillation output at a frequency of VCO 17) f−f+xloolxN (where N is an integer) is supplied to
/ (1001X N'). Frequency dividing circuit 5
As shown in FIG. 2(C), the frequency j, / -f/(10
01XN) is phase-compared with the frame synchronization pulse P1 by the phase comparator 3, and the oscillation frequency of the VCO 4 is controlled by the output phase error signal of the phase comparator 3.

The oscillation output of the VCO 4 is supplied as a master clock to the frequency divider circuit 6 and frequency-divided by 1/(1000XN). As a result, as shown in FIG. 2(D), < f 2 = f +
A frame synchronization pulse P2 having a frequency of x (1001/1000) is output from the frequency dividing circuit 6. In this example, it is fz-30Hz. The video synchronization signal generation circuit 7 is
A second video synchronization signal S2 shown in FIG. 2(E) which is synchronized with the first video synchronization signal $1 and has a frame frequency f2 based on the frame synchronization pulse P2 is generated, and this second video synchronization signal Signal $2 is output from output terminal 8. The frame extraction circuit 2, the phase comparator 3, the VCO 4, the frequency dividing circuit 5.6, and the video synchronization signal generation circuit 7 are first means for generating and outputting the second video synchronization signal s2 from the first video synchronization signal S1. Configure.

On the other hand, the first time code TC+ of SMPTE in drop frame mode synchronized with the first video synchronization signal s1 is applied to the input terminal 9, and the time code monitor circuit 1
0. The time code monitor circuit 10 has a configuration shown in FIG. 3, for example. The time code monitor circuit 10 includes a time code reader 20 that reads the first time code TC+, and a terminal 22 that uses a portion of the read time code other than the skip portion as loading data.
The time code loading controller 21 supplies the time code to the time code generation circuit 11 via the time code generating circuit 11. The time code loading controller 21 is configured to load the time code at regular intervals (that is, only during the period between skip parts).
The configuration may be such that the loading data is supplied to the time code generation circuit 11, or the configuration may be configured such that only the first portion of the loading data is supplied to the time code generation circuit 11.

The time code generation circuit 11 is synchronized with the second video synchronization signal @S2 in response to the frame synchronization pulse P2 from the frequency dividing circuit 6 based on the loading data from the time code monitor circuit 10, and is synchronized with the second video synchronization signal @S2. A second time code TCz that matches the code TC+ in real time is generated. This second time code TC2 is a non-drop frame mode SMPTE time code and is output from the output terminal 12. When loading data is supplied at regular intervals, the time code generation circuit 11 interpolates the skip portion in response to the frame synchronization pulse P2 during the period between loadings. On the other hand, when only the first part of the loading data is supplied, it starts from the reference loading data and thereafter generates an SMPTE time code in non-drop frame mode in response to the frame synchronization pulse P2.

The time code monitor circuit 10 and the time code generation circuit 11 constitute a second means for generating and outputting a second time code TC2 from the first time code TC+.

FIG. 4 is a block diagram for explaining an example of application of the device of the present invention. In the figure, a video signal source 25 is, for example, a magnetic tape video signal recording/reproducing device, and a color video signal of the NTSC color television system from the video signal source 25 is supplied to a terminal 28. The device of the present invention has this terminal 28
Digital audio for color video signals from
This allows a digital audio signal from a digital audio system with a sampling frequency of 44.1kllZ to be used as a mask. Video synchronization signal S1 from video signal source 25 and SMPTE in drop frame mode
The time code TC+ is supplied to a synchronizer 26 according to the invention. Synchronized bag fi! 26 is the video synchronization signal S2 and the non-drop frame mode SMP as described above.
A TE timecode reader is provided to the digital audio system 27.

The digital audio system 27 samples the input analog audio signal from the terminal 29 at a sampling frequency of 44.1 kHz.
This is a system that samples digital audio signals in z and outputs them to a terminal 30, and includes, for example, a business-use PCM encoder/decoder. Since the digital audio system 27 is synchronized by the video synchronization signal S2 from the synchronization bag W126 and is supplied with the SMPTE time code TC2 in non-drop frame mode (i.e., real time), the digital audio system 27 receives the digital signal from the terminal 30. The audio signal can be used as a digital audio mask for the color video signal from terminal 28. This is because the video synchronization signal S2 is synchronized with the first video synchronization signal S1, although the frame frequency is different from the video synchronization signal S+ from the video signal source 25, and furthermore, the time code TC2 is synchronized with the video synchronization signal S2. This is because it matches the time code TC+ in real time.

Effects of the Invention As described above, according to the present invention, the first time code is synchronized with the first time code synchronized with the first time code.
a second video synchronization signal that is synchronized with the video synchronization signal and has a different frame frequency; and a second time code that is synchronized with the second video synchronization signal and matches the first time code in real time. For example, even if the frame frequency of the first video synchronization signal is 29.971-12, a second video synchronization signal with a frame frequency of 30 Hz is obtained and a sampling frequency of 44.1 kHz is obtained. By synchronizing the digital audio system used, it is possible to prevent the sampling frequency from shifting to 44.0561-(Z), and even if the first time code is a drop frame mode code, it is possible to prevent the sampling frequency from shifting to 44.0561-(Z). mode, it is possible to use the output digital audio signal of the digital audio system as a digital audio mask for the color video signal with a frame frequency of 29.97 H2, etc. It has a number of features.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the device of the present invention;
2 is a timing chart for explaining the operation of the block system in FIG. 1, FIG. 3 is a block diagram showing an embodiment of the time code monitor circuit in FIG. 1, and FIG. 4 is an example of application of the device of the present invention. FIG. 2 is a block diagram for explanation. 2... Frame extraction circuit, 3... Phase comparator, 4...
...vCQ, 5, 6... Frequency dividing circuit, 7... Video synchronization signal generation circuit, 9... Input terminal, 10... Time code monitor circuit, 11... Time code generation circuit, 2
0... Time code reader, 21... Time code 0-ding controller, 25... Video signal source, 2
6...Synchronization device, 27...Digital audio
system. Patent applicant: Victor Japan Co., Ltd. Figure 1 Figure 3 Figure 4

Claims (3)

[Claims] (1) A first means for generating and outputting a second video synchronization signal that is synchronized with the first video synchronization signal and has a different frame frequency from a first video synchronization signal; A second means for generating and outputting a second time code that is synchronized with the second video synchronization signal and matches the first time code in real time from the synchronized first time code. A synchronization device characterized by: (2) The frame frequency of the first video synchronization signal is 29
．． 97 kHz, and the frame frequency of the second video synchronizing signal is 30 kHz, the synchronizing device according to claim 1. (3) The synchronization device according to claim 1, wherein the first time code is a drop frame mode time code, and the second time code is a non-drop frame mode time code. .