JPH0446479A - MUSE signal recording and reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a MUSE that records and reproduces MUSE signals.
The present invention relates to an E signal recording/reproducing apparatus, and more specifically, to a MUSE signal recording/reproducing apparatus which facilitates the separation of three-level synchronization signals during reproduction.

[Conventional technology]

High-definition is a completely new television system developed to meet the demand for higher quality television images, and is already being put into practical use in many fields including broadcasting. Furthermore, in response to this, development of high-definition equipment such as television receivers and VTRs is progressing.

In the transmission of such high-definition video signals, M
US E (Multiple 5ub-nyqu
A band compression method called the istSa+springEncoding) method is adopted to make effective use of the transmission band. Transmission using this) 4USE method is
This is achieved by sample value transmission in which sample values of a high-definition signal are thinned out and transmitted, and a decoder on the receiving side interpolates the data to restore the sample values. In addition, when transmitting video signals using the MUSE method, in order to reproduce a good image on the receiving side, it is necessary to minimize distortion in phase and amplitude, and to keep the resampling phase correct, just as in normal waveform transmission. It is.

By the way, when recording and reproducing video signals transmitted by the MUSE method (hereinafter referred to as MUSE signals) using a recording and reproducing device such as a VTR, motors and mechanical parts that constitute the rotating magnetic head and tape running system are used. Due to variations in assembly accuracy, jitter (time axis fluctuation) occurs in the reproduced MUSE signal. For this reason, recording and reproducing devices are equipped with a time axis correction circuit to remove the above-mentioned jitter, and in order to operate this time axis correction circuit, a ternary synchronization signal, etc. is separated from the MUSE signal during playback. It is now used as a control standard.

However, in the above recording and reproducing apparatus, the three-value synchronization signal in the MUSE signal (see (a) in FIG. 4) has an amplitude of about 50% of the color signal C and the luminance signal Y, and the IH (horizontal scanning period ), so when separating the three-level synchronization signal during playback, it is necessary to apply synchronization separation that uses the amplitude difference between the chrominance signal C and the luminance signal Y, like a binary synchronization signal. I can't.

Therefore, conventionally, synchronization separation has been performed by a method that does not utilize the above-mentioned amplitude difference. For example, in the configuration shown in FIG. 3, the reproduced MUSE signal shown in FIG. It has become. This subtractor 11
By subtracting the delayed MUSE signal delayed by IH by the IH delay circuit 12 ((b) in the same figure) from the MUSE signal, the amplitude becomes 2 as shown in (C) in the same figure.
A ternary synchronization signal that is doubled is obtained.

In the case of the above synchronization separation, there is no problem if the phase of the reproduced MUSE signal is stable, but if jitter occurs in the reproduction MUSE signal, the above synchronization separation cannot be performed due to the phase shift due to the jitter. It disappears. Therefore, in this case, it is necessary to perform synchronization separation so as not to be affected by jitter.

For example, in the configuration shown in FIG. 5, the ternary synchronization signal is separated based on the burst signal and the additional synchronization signal added to the MUSE signal during recording. In this configuration, the chrominance signal C and the luminance signal Y are compressed in the time domain, and the compressed MUSE signal (shown in (a) of FIG. 6) is obtained by adding a negative polarity additional synchronization signal and a burst signal to the remaining period. , the synchronization separation circuit 13 separates the additional synchronization signal shown in FIG. The monostable multivibrator 14 (MM in the figure) 14 and 15 is input to this additional synchronization signal, and the gate pulse shown in (c) of the figure is output from the monostable multivibrator 14 at the rising edge of the additional synchronization signal. On the other hand, the monostable multi-bi break 15 outputs a time t from the rise of the additional synchronization signal.
The gate pulse shown in (e) of the same figure is output with a delay of .times.

On the other hand, the compressed MUSE signal is also input to the gate circuits 16 and 17, and the gate circuit 16 uses the gate pulse obtained from the monostable multi-by-break 14 as shown in FIG.
The burst signal shown in d) is extracted and sent to the gate circuit 17.
Then, the gate pulse obtained from the monostable multivibrator 15 extracts the three-value synchronization signal shown in (f) of the figure.

The burst signal extracted in this manner is used in the time base correction circuit to detect time base fluctuations, and the ternary synchronization signal is used as a memory control signal in the time base correction circuit.

[Problem to be solved by the invention]

However, in the configuration shown in FIG. 5, the chrominance signal and the luminance signal are time-base compressed when adding the additional synchronization signal and burst signal in order to obtain the compressed MUSE signal, as described above. Therefore, expensive memory and complicated control circuits are required, which has been an obstacle to making recording/reproducing devices smaller and cheaper.

The present invention has been made in view of the above circumstances, and includes:
It is an object of the present invention to make it possible to separate a ternary synchronization signal based on the amplitude difference between a chrominance signal and a luminance signal, and to simplify and reduce the cost of a circuit configuration for realizing synchronization separation.

[Means to solve the problem]

A MUSE signal recording and reproducing apparatus according to the present invention is a MUSE signal recording and reproducing apparatus that records and reproduces MUSE signals, and is characterized in that it is configured as shown below in order to solve the above problems.

That is, the above MUSE signal recording and reproducing apparatus includes a polarity matching means for matching all the polarities of the three-value synchronization signals in the MUSE signal during recording, and a negative polarity signal of the three-value synchronization signals whose polarities are all matched by the polarity matching means. and amplitude expansion means for expanding the amplitude of the signal in the direction of the black level so that the negative polarity side has a larger amplitude than the chrominance signal and the luminance signal.

[For production]

The polarity of the three-value synchronization signal of the MUSE signal is inverted every 1H, but the polarity matching means brings all the polarities into a matching state. In this way, the MUSE signal in which all the three-level synchronization signals have the same polarity is processed by the amplitude expansion means so that the amplitude of the negative polarity signal among the three-level synchronization signals becomes larger than the chrominance signal and the luminance signal on the negative side. The amplitude is expanded in the direction of the black level and becomes the MUSE signal for recording.

Thereby, when reproducing the MUSE signal that has been processed as described above, it is possible to perform synchronization separation using the amplitude difference between the chrominance signal and the luminance signal.

〔Example〕

An embodiment of the present invention will be described below based on FIGS. 1 and 2.

The MUSE signal recording and reproducing apparatus according to this embodiment includes a polarity matching means 1 and an amplitude expansion circuit 2, as shown in FIG. The polarity matching means 1 includes an IH delay circuit 3, a subtracter 4, a pulse width detection circuit 5, and a flip-flop 6.
, an AND circuit 7 , and a polarity inversion circuit 8 .

The IH delay circuit 3 is a circuit that delays the input MUSE signal before recording by IH and outputs a delayed MUSE signal. The subtracter 4 is a circuit to which the input MUSE signal and the delayed MUSE signal are input, and subtracts the delayed MUSE signal from the input MUSE signal. ) is removed, and only the synchronization signal (3) is separated.

The pulse width detection circuit 5 is a circuit that outputs a single width detection pulse having the same period as the ternary synchronization signal separated by the subtracter 4 and having a width matching the width of the ternary synchronization signal. flip flop 6
The above width detection pulse is divided into 1/2 frequency to obtain 1/2 frequency.
This is a circuit that outputs a pulse divided by two. AND circuit 7 is
This circuit outputs a gate pulse by calculating the logical sum of the width detection pulse and the 1/2 frequency division pulse. The polarity inversion circuit 8 inverts the polarity of the three-value synchronization signal during the period in which the gate pulse is outputted among the three-value synchronization signals in the input MUSE signal, and creates a pseudo image in which the polarities of all three-value synchronization signals match. This is a circuit that outputs a MUSE signal.

The amplitude expansion circuit 2 as an amplitude expansion means is composed of non-linear elements such as diodes, and the above-mentioned pseudo MUSE
This circuit expands the amplitude of a negative polarity signal among the three-value synchronization signals in the direction of the black level so that the negative polarity side has a larger amplitude than the color signal C and the luminance signal Y.

When recording with the above configuration, as shown in FIG.
The USE signal is directly input to the subtracter 4, and is also input to the subtracter 4 as a delayed MUSE signal (shown in (b) of the figure) which is delayed by IH by the IH delay circuit 3. In the subtracter 4, the delayed MUSE signal is subtracted from the input MUSE signal, and as shown in (C) of the figure, the chrominance signal C and the luminance signal Y are removed, while the 3-value signal with doubled amplitude is generated. Only the synchronization signal will be separated. Furthermore, at this time,
Since there is no jitter in the human-powered MUSE signal, the ternary synchronization signal can be accurately separated.

When the three-value synchronization signal output from the subtractor 4 is input to the pulse width detection circuit 5, a width detection pulse having the same width as the three-value synchronization signal as shown in (d) of the figure is output from here. .

This width detection pulse is directly input to the AND circuit 7, and is frequency-divided to 1/2 by the flip-flop 6.
The pulse is input into the AND circuit 7 as a 1/2 frequency-divided pulse as shown in FIG. The AND circuit 7 takes the logical sum of both pulses and outputs a gate pulse as shown in (f) of the figure.

The input MUSE signal is also input to a polarity inversion circuit 8, where the polarity of the three-value synchronization signal during the gate pulse period is inverted, as shown in (g) in the figure. , a pseudo MUSE in which the polarities of the three-level synchronization signals all match.
The signal is input to the amplitude expansion circuit 2 as a signal. In the amplitude expansion circuit 2, the amplitude of the negative polarity signal among the three-value synchronization signals in the pseudo MUSE signal is expanded in the direction of the black level. A recording MUSE signal is obtained in which the signal has a larger amplitude than the color signal C and the luminance signal Y on the negative side.

By the way, in order to restore the ternary synchronization signal subjected to polarity matching and amplitude expansion as described above to its original polarity and amplitude at the time of reproduction, it is sufficient to perform a process opposite to the above process.

In this way, according to this embodiment, since the polarity matching and amplitude expansion of the three-level synchronization signal are performed during recording, the amplitude difference between the color signal C and the luminance signal Y is used during playback. , synchronization can be easily separated from the recorded MUSE signal.

〔Effect of the invention〕

As described above, the MUSE signal recording and reproducing apparatus according to the present invention includes a polarity matching means for matching all the polarities of the three-value synchronization signals in the MUSE signal during recording, and a three-value synchronization signal whose polarities are all matched by the polarity matching means. Among them, the amplitude expanding means expands the amplitude of the negative polarity signal in the direction of the black level so that the negative polarity side has a larger amplitude than the chrominance signal and the luminance signal, so that the polarity matches and the amplitude The MUSE signal having the three-value synchronization signal whose amplitude has been expanded by the expansion means is used as the MUSB signal for recording. Therefore, during reproduction, synchronization separation can be performed using the amplitude difference between the chrominance signal and the luminance signal. Additionally, as a result, processing such as adding an additional synchronization signal or burst signal to the MUSE signal during recording, or compressing the time axis of the color signal and luminance signal in order to secure the space necessary for this addition, is now no longer possible. This eliminates the need to provide expensive memory, complicated control circuits, etc. used for the above-mentioned signal addition and time base compression.

Therefore, if the present invention is adopted, synchronization separation during reproduction can be facilitated, and the cost of the MUSE signal recording and reproducing apparatus can be reduced and the circuit configuration can be simplified.

[Brief explanation of drawings]

1 and 2 show one embodiment of the present invention. FIG. 1 is a block diagram showing the configuration of the main parts of the MUSE signal recording and reproducing apparatus. FIG. 2 is a time chart showing the operation of each of the main parts shown in FIG. 3 to 6 show conventional examples. FIG. 3 is a block diagram showing the configuration of a circuit that separates three-value synchronization signals. FIG. 4 is a time chart showing the operation of each part of the circuit shown in FIG. FIG. 5 is a block diagram showing the configuration of another circuit for separating three-value synchronization signals. FIG. 6 is a time chart showing the operation of each part of the circuit shown in FIG. 1 is a polarity matching means, 2 is an amplitude expansion circuit (amplitude expansion means)
It is. Patent applicant Sharp Corporation Figure 6

Claims (1)

[Claims] 1. A MUSE signal recording and reproducing device that records and reproduces a MUSE signal, which includes a polarity matching means for matching the polarities of all three-value synchronization signals in the MUSE signal during recording, and a polarity matching means for changing the polarity by the polarity matching means. Among the three-level synchronization signals that all match, the negative polarity signal is
1. A MUSE signal recording/reproducing device comprising: amplitude expanding means for expanding the amplitude in the direction of the black level so that the negative polarity side has a larger amplitude than the chrominance signal and the luminance signal.