JPH0392092A - External synchronizing circuit for muse signal - Google Patents

Abstract

PURPOSE:To form a reproduced MUSE signal phase-locked to an external synchronizing signal by correcting a readout timing of a frame memory according to an output of a phase comparison means comparing the phase of a frame synchronizing signal led from a MUSE decoder and the phase of the external synchronizing signal. CONSTITUTION:A frame memory 5 storing a MUSE signal, a phase comparison means 7 comparing phases of a frame synchronizing signal and an external synchronizing signal obtained from a MUSE decoder 3 and a memory control means 24 correcting a readout timing of the frame memory 5 with the output of the phase comparison means 7 are arranged respectively to a MUSE synchronizer (variable delay device) 2. Thus, the delay of the MUSE signal is controlled in following to an external synchronizing signal and the MUSE signal whose phase is matched with the external synchronizing signal is formed and led out.

Description

[Detailed description of the invention] (b) Industrial application field The present invention relates to an external synchronization circuit for MSE signals.

(Mouth) 1 come and 1 branch ML! Regarding a video disc player that reproduces SE signals, Japanese Patent Application Laid-Open No. 61-77480 (}10
4N5/9 2), taking into consideration that horizontal synchronization separation of MUSE signals is not easy, a constant frequency pilot signal is frequency-multiplexed and recorded on an FM-MUSE signal,
By comparing the phases of the reproduction pilot signal and the reference signal, the rotation of the disk motor and the jitter correction mirror installed in the pickup are controlled to eliminate jitter during reproduction.

(C) Problems to be Solved by the Invention However, the above-mentioned conventional technology synchronizes the rotation of the disk motor with a fixed oscillation output, and the reproduction ML
It has been difficult to externally synchronize the ISE signal.

Therefore, the present invention provides a reproduction MU that is phase synchronized with an external synchronization signal.
The purpose is to derive the SE signal in its form.

(2) Means for Solving the Problems The present invention provides a frame memory for storing MUSE signals;
A phase comparison means for comparing the phases of the frame synchronization signal obtained from the MUSE decoder and an external synchronization signal, and a memory control means for correcting the read timing of the frame memory based on the output of the phase comparison means are each provided in a variable delay device. It is characterized by being arranged.

(e) According to the present invention, the MU follows the external synchronization signal.
The amount of delay of the SE signal is controlled, and a MUSE signal whose phase is matched to the external synchronization signal is formed or derived.

(f) Example Hereinafter, the present invention will be explained according to an illustrative embodiment.

FIG. 1 shows a circuit block diagram of this embodiment. In this embodiment, the output of a high-definition video disc player 1, which is a MUSE signal source, is transmitted to a Mu, IsE decoder through a MUSE synchronizer 2, which is a variable delay device. The present invention is applied to a high-definition video playback system that is manually operated.

First, in this embodiment, the reproduced MSE signal obtained from the high-definition video disc player 1 is manually inputted to the MUSE synchronizer 2.

The high-definition video disc player 1 has a built-in time base collector, and the playback II;SE signal is converted into an AD converter 9! in the MUSE synchronizer 2. At #4, the data is digitized using a fixed clock and stored in the frame memory 5.

The digital signal read out from the frame memory 5 is input to the DA conversion circuit 6 and converted into an analog signal.
The signal is input to the same SE decoder 3.

In the MUSE decoder 3, the input MUSE signal is input to an AD conversion circuit 9 via a low-pass filter 8 and digitized, and its output is input to a synchronization control separation circuit 10 and an input switching circuit 11.

The synchronization control separation circuit 10 receives a horizontal synchronization signal,
Frame synchronization signals, various control signals multiplexed during the vertical blanking period, and compressed digital audio signals are separated and derived.

The input switching circuit 11 alternately selects and derives the data read out from the memory 12 one frame before and the AD converted data. This selection data is the interframe interpolation circuit]
3, a field interpolation circuit 14, and a motion detection circuit 16.

The output of the interframe interpolation circuit 13 is input to an interfield interpolation circuit 15 to form still image data. Note that a control signal such as a motion vector signal is used in this interpolation process.

Further, the intra-field interpolation circuit 14 outputs moving image data.

The MIX circuit 17 mixes the still image data and the moving image data according to the output of the motion detection means 16, and inputs the mixture to the TCI decoding circuit 21 at the next stage. The decoded output derived from the synchronization is three primary color video data, each of which is DA
It is derived as a three primary color video signal via a conversion circuit 22 and a low-pass filter 23.

Note that the separated compressed audio data is time-axis expanded by 8 in time-axis expansion j%, inputted to the audio decoder 19, converted into a predetermined audio signal, and derived.

Also, a synchronization detection circuit 20 inputting the separated synchronization signal
derives the frame synchronization pulse in a form.

This frame synchronization pulse is the MUSE synchronizer 2
It is used as a comparison input of the phase comparator circuit 7 inside. The phase comparator circuit 7 detects a phase error of a frame synchronization pulse with respect to an external synchronization signal of a frame period, which is a reference input. The memory control means 24, which controls writing and reading of the frame memo J5, changes the read address, which was freely generated in the initial state, according to the amount of phase error obtained by phase comparison.

As a result, the phase of the digital MUSE signal derived from the frame memory 5 is changed according to the amount of change in the read address, and the phase of the three primary color video signals derived is made to match the phase of the external synchronization signal.

In this embodiment, the phase of the video signal to be output is made to match the phase synchronization signal, but if necessary, the video signal may be configured to be output with a predetermined phase shift with respect to the external synchronization signal. Needless to say, this is a good thing.

(g) Effects of the Invention According to the present invention, it is possible to drive a video disc player in external synchronization, and the effect is great.

[Brief explanation of drawings]

FIG. 1 shows a circuit block diagram of an embodiment of the present invention.

Claims (1)

[Claims] (1) In a high-definition video playback system comprising a MUSE signal source, a variable delay device, and a MUSE decoder connected in a subordinate manner, the frame memory stores the output of the MUSE signal source, and the output of the MUSE decoder is derived from the MUSE decoder. phase comparison means for comparing the phases of a frame synchronization signal and an external synchronization signal; and memory control means for correcting the read timing of the frame memory according to the output of the phase comparison means, each of which is disposed in the variable delay device. External synchronization circuit for MUSE signal.