JPH08163589A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE: To provide a magnetic recording and reproducing device compensating timewise deviation of a luminance signal and a color signal and enabling the reproduction in which the degradation of an EDTV 2 signal is eliminated. CONSTITUTION: In a magnetic recording/reproducing device processing a wide television signal in a luminance signal processing circuit and a color signal processing circuit, the circuit is provided with a reference signal addition means 24 adding reference signals to the input signals of a luminance signal recording processing circuit and a color signal recording processing circuit, detection means 26 to 28 detecting the timewise deviation of the reference signals in the outputs of a luminance signal reproduction processing circuit and a color signal reproduction processing circuit and a compensation means 29 compensating this timewise deviation and adjusting the output timing of a luminance signal and a color signal. Even when an EDTV signal 2 is recorded, the timewise positional relation of the luminance signal, color signal and reinforcing signal of the EDTV 2 signal to be reproduced can be exactly matched. When the reproduced output is decoded in an EDTV 2 exclusive receiver, reproduced video of high-image quality is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus used for recording / reproducing a video signal, and more particularly to a new television broadcasting system, EDTV (extended definition te).
It is possible to reproduce high-quality images by recording the signal of (levision).

[0002]

2. Description of the Related Art In recent years, a new television broadcasting system replacing the conventional NTSC system has been studied.
One of them is a so-called second-generation ED, which is a wide-screen television signal that transmits an image of a progressive scan system with an aspect ratio of 16: 9 while maintaining compatibility with the NTSC system.
There are TV signals (hereinafter referred to as EDTV2 signals), 19
In December 1993, the provisional specifications were established (Kenrokukan Publishing "Broadcasting Technology" May 1994 issue, pp.123.
-131).

This EDTV2 signal is a transmission method called a letterbox system. Of the conventional about 480 effective scanning lines, 360 lines in the central part (main image part) transmit a 16: 9 wide screen, and the remaining upper and lower parts. The 120 lines of the part (non-image part) are used to transmit two kinds of reinforcement signals (vertical time reinforcement signal VT and vertical high frequency reinforcement signal VH) for improving the vertical resolution. Further, a reinforcement signal (horizontal high-frequency reinforcement signal HH) for improving the horizontal resolution is frequency-multiplexed in the blow-out hole which is a portion conjugate with the color signal of the main image portion in the vertical-time frequency domain. Further, an identification control signal in which the aspect ratio, the presence / absence of various reinforcement signals, and the position reference of the reinforcement signal are multiplexed is multiplexed in the 22nd line and the 285th line.

When the EDTV2 signal is received by a dedicated wide-screen television receiver, the above-mentioned reinforcing signal is decoded and the interlaced scanning is converted into the progressive scanning to obtain an extremely high quality image with an aspect ratio of 16: 9. Can be restored. Since the EDTV2 signal is compatible with the NTSC system, it can be received by a general television receiver, and in this case, it has a non-image part at the top and bottom.
A 6: 9 landscape image is displayed on the screen.

The EDTV2 signal is a conventional VH signal.
It is possible to record with a consumer magnetic recording / reproducing apparatus such as the S system, and output a reproduction signal to a dedicated image receiving device or a general image receiving device to reproduce an image. When the EDTV2 signal is input to this consumer magnetic recording / reproducing apparatus, focusing on the frequency spectrum of the reinforcing signal, the HH signal and the VT signal are separated as a color signal, and the VH signal is separated as a luminance signal and processed. Become.

The signal processing of the luminance signal and the color signal of the conventional magnetic recording / reproducing apparatus will be described below.

A conventional VHS type magnetic recording / reproducing apparatus is
As shown in FIG. 9, the recording side includes an input terminal 1 for inputting a video signal and a YC separation circuit 2 for separating the video signal into a luminance signal and a chrominance signal. , A low-pass filter (LPF) 3 that limits the frequency band of the luminance signal, an emphasis circuit 4 that emphasizes high-frequency components, and a clipping circuit 5 that clips the signal level.
An FM modulation circuit 6 for FM-modulating the signal, and a high-pass filter (HP) for limiting the band of the FM-modulated luminance signal.
F) 7, and as a color signal recording processing circuit, a band pass filter (BP) for limiting the band of the color signal.
F) 8 and a low frequency conversion circuit 9 for converting the frequency of the color signal to the low frequency range, and further, the low frequency converted color signal and FM.
An adder 10 that forms a recording video signal by adding the modulated luminance signal, a recording amplifier 11 that adjusts the level of the recording video signal, and a recording head 12 that records the recording video signal on a magnetic tape 13 are provided. It has.

On the reproducing side, a reproducing head 14 for reading the recorded video signal from the magnetic tape 13 and a reproducing amplifier 15 for amplifying the read video signal are provided. A high-pass filter 16 that extracts a luminance signal from the amplified video signal, a limiter circuit 18 that limits the amplitude of the luminance signal, an FM demodulation circuit 19 that FM demodulates this signal, and a de-emphasis circuit 20 that suppresses high frequency components of the signal. And a LPF 17 for extracting a color signal from the amplified video signal as a color signal reproduction processing circuit, and a high frequency conversion circuit 21 for converting the frequency of the color signal to the original state. It is provided with an adder 22 for adding the generated luminance signal and color signal to form a reproduced video signal, and an output terminal 23 for outputting the reproduced video signal.

In this magnetic recording / reproducing apparatus, when a video signal (NTSC signal) is input to the input terminal 1, the video signal is first separated into a luminance signal and a chrominance signal by the YC separation circuit 2. The separated luminance signal is passed through the low pass filter 3
Signal band determined in advance by the VHS method (about 3M in the VHS method)
Hz, about 5 MHz in the S-VHS method), and then the emphasis circuit 4 emphasizes high frequency components.
Then, the clipping circuit 5 clips the white peak and the black peak to a predetermined level, and shapes the signal amplitude into a signal within a certain dynamic range. This signal is the next FM
The modulation circuit 6 performs FM modulation, the high-pass filter 7 band-limits the signal to a predetermined signal band, and the processing of the luminance signal ends.

On the other hand, the color signal separated by the YC separation circuit 2 is sub-carrier 3.58 of the color signal by the band pass filter 8.
After being limited to the upper and lower bands of about 500 kHz centering around MHz, the low frequency conversion circuit 9 performs low frequency conversion so that the subcarrier becomes 629 kHz. The low-frequency converted color signal and the FM-modulated luminance signal are added by the adder 10 to form a frequency-multiplexed recording video signal. And tape
It is amplified by the recording amplifier 11 so as to have an optimum level for the head system, and recorded on the magnetic tape 13 by the recording head 12.

During reproduction, the video signal recorded on the magnetic tape 13 is read by the reproducing head 14 and amplified by the reproducing amplifier 15 to a predetermined level, and then the high-pass filter 16 and the low-pass filter 17 convert it into a luminance signal and a color signal. And each reproduced signal processing is performed.

The amplitude of the separated luminance signal is limited by the limiter circuit 18 for FM demodulation, and the FM demodulation circuit 19
Given to. The signal demodulated by the FM demodulation circuit 19 is FM
Although there is triangular noise peculiar to transmission, this noise disappears as the high-frequency component of the signal is suppressed by the de-emphasis circuit 20. In this way, the distortion component is reduced, and the luminance signal with improved signal-to-noise ratio (SNR) is demodulated.

Regarding the color signals, the subcarrier 629 kHz of the color difference signals is converted to the original 3.58 MHz by the high frequency conversion circuit 21, contrary to the recording operation. Then, it is added with the luminance signal demodulated by the adder 22 to form a reproduced video signal, which is output from the output terminal 23.

[0014]

In this conventional magnetic recording / reproducing apparatus, since the signal processing circuits for the luminance signal and the color signal are different, the propagation delay time due to the signal processing is different between the luminance signal and the color signal. As a result, in the reproduced video signal, a time lag occurs between the luminance signal and the chrominance signal. However, the time difference between the luminance signal and the color signal is about several hundred ns, and from the viewpoint of human visual characteristics, even if there is a deviation, it does not pose a problem in practice, so it is currently not strictly controlled. is there.

However, in this conventional magnetic recording / reproducing apparatus, E
When a DTV2 signal is recorded and played back by a dedicated receiver, if the processing time difference between the luminance signal processing circuit and the chrominance signal processing circuit exists, the positional relationship between the video signal of the main picture portion and the reinforcement signal shifts. The quality of the reproduced image deteriorates significantly. Therefore, in order to prevent this image quality deterioration, it is necessary to reduce the time lag between the luminance signal and the color signal of the reproduced video signal. In particular, in the case of the vertical reinforcement signals VT and VH, since they are compressed to one-third on the time axis, the allowable value of the time shift is stricter. The value must be 70 ns or less.

[0016] Further, if the time lag is adjusted only by the initial adjustment, the lag again occurs due to the change with time thereafter.

The present invention solves these conventional problems, and it is possible to compensate for the time lag between the luminance signal and the chrominance signal with a simple structure, and thereby, the EDTV 2 without deterioration of the image quality. It is an object of the present invention to provide a magnetic recording / reproducing device capable of decoding a signal.

[0018]

In view of the above, the present invention provides a luminance signal processing circuit for a wide television signal in which a plurality of reinforcing signals for improving image quality and an identification signal for identifying a signal form are multiplexed. In a magnetic recording / reproducing apparatus for processing by a color signal processing circuit, reference signal adding means for adding a reference signal to an input signal of a luminance signal recording processing circuit and a color signal recording processing circuit, a luminance signal reproduction processing circuit and a color signal reproduction A detection means for detecting the time shift of the reference signal in the output of the processing circuit and a compensation means for compensating the time shift and adjusting the output timing of the luminance signal and the color signal are provided.

Further, the reference signal adding means forms a reference signal by using a signal included in the wide television signal,
It is configured to be added to the input signal of the luminance signal recording processing circuit or the color signal recording processing circuit.

Further, the reference signal adding means is configured to generate a reference signal in synchronization with the input wide television signal and add it to the input signals of the luminance signal recording processing circuit and the color signal recording processing circuit. .

Further, the reference signal adding means is constructed so that the polarities of the reference signals added to the input signals of the luminance signal recording processing circuit and the color signal recording processing circuit are different from each other.

Identification signal input means for inputting the identification signal of the wide television signal to both the luminance signal recording processing circuit and the color signal processing circuit, and identification in the output signals of the luminance signal reproduction processing circuit and the color signal reproduction processing circuit. A detection means for detecting a temporal shift of the signal and a compensating means for compensating for the temporal shift and adjusting the output timing of the luminance signal and the color signal are provided.

[0023]

Therefore, by compensating the time difference between the luminance signal and the chrominance signal at the time of reproduction by using the reference signal, it is possible to eliminate the time lag between them. Therefore, regardless of whether the EDTV2 signal is input and the reinforcement signal is processed by either the luminance signal processing circuit or the color signal processing circuit, the luminance signal, the color signal, and the reinforcement signal of the EDTV2 signal to be reproduced are temporally changed. It is possible to accurately match the positional relationship.
As a result, the reproduction output of the magnetic recording / reproducing apparatus of the present invention is ED.
When decoded on a wide television dedicated to TV2,
It is possible to obtain a high quality reproduced image.

[0024]

【Example】

(First Embodiment) The magnetic recording / reproducing apparatus of the first embodiment uses a color burst signal of a color signal as a reference signal to compensate for a time difference between a color signal and a luminance signal. As shown in FIG. 1, this apparatus divides a YC-separated color signal into a recording side, and a reference signal detection circuit 24 for extracting a color burst signal from the color signal, and an extracted color burst signal and a luminance signal. A reference signal detection circuit 26 for detecting the reference signal (color burst signal) of the color signal and a reference signal for detecting the reference signal (color burst signal) added to the luminance signal on the reproducing side A detection circuit 27, a time difference detection circuit 28 that detects a time difference between reference signals, and a delay circuit that delays a luminance signal based on the detected time difference.
29 and. Other configurations are conventional devices (Fig. 9)
There is no change.

In this magnetic recording / reproducing apparatus, when the EDTV2 signal is input to the input terminal 1, the YC separation circuit 2 separates it into a luminance signal and a color signal. The luminance signal output terminal of the YC separation circuit 2 outputs the luminance signal, the VH signal and the identification control signal, and the color signal output terminal outputs the color signal, the HH signal and the VT signal.

In this apparatus, since the color burst signal of the color signal is used as the reference signal, the reference signal detection circuit 24 extracts the color burst from the color signal and adds it to the back porch of the horizontal synchronizing signal of the luminance signal by the adder 25. .

FIG. 2 is a waveform diagram for explaining the addition of the above-mentioned reference signal. In FIG. 2, the input signal (see FIG.
(A)) is a luminance signal in the YC separation circuit 2 (FIG. 2 (b)).
And a color signal (FIG. 2C), and a color burst signal is added to the separated luminance signal as a reference signal (FIG. 2D).

Thus, the luminance signal to which the color burst signal which is the reference signal is added immediately after YC separation and the color signal originally having the color burst signal are the same signal recording processing circuit as in the conventional magnetic recording / reproducing apparatus. After signal processing, it is recorded on the magnetic tape 13. Even during reproduction, the luminance signal and the chrominance signal are extracted again through the same signal reproduction processing circuit as in the conventional case. However, since these two signals have passed through different transmission channels, the temporal positional relationship of the signals is deviated. It is in.

FIG. 3 is a timing chart for detecting the time difference between the luminance signal and the color signal output from the luminance signal reproduction processing circuit and the color signal reproduction processing circuit. The color signal is delayed with respect to the luminance signal. The case is shown. First,
The reference signal detection circuit 27 detects the first rising zero-cross point of the color burst signal (FIG. 3A) of the luminance signal, and generates the reference pulse of the luminance signal in mono-multi (FIG. 3C). The reference signal detection circuit 26 performs the same processing on the reference signal of the color signal to generate the reference pulse of the color signal (FIGS. 3B and 3D). Then, the time difference detection circuit 28 triggers at the rising edges of these two reference pulses and generates a pulse whose pulse width indicates the time difference between the luminance signal and the color signal (FIG. 3 (e)). The delay circuit 29 controls the delay time using this pulse and delays the luminance signal that was preceding in time,
Match the output timing of the luminance signal and the color signal.

If the luminance signal is delayed, it is necessary to provide a delay circuit in the color signal reproduction processing circuit.

Further, although the color burst signal is used as the reference signal in the apparatus of the first embodiment, a horizontal synchronizing signal included in the luminance signal may be used. In that case, the horizontal synchronizing signal is added to the input signal of the color signal recording processing circuit, the horizontal synchronizing signal is detected in the reproduction processing circuit, and the edge portion is compared to obtain the time difference between the luminance signal and the color signal. it can.

Further, in the first embodiment, an example in which the common reference signal is used for the luminance signal and the color signal has been shown, but two types of reference signals whose positions are temporally different are used as the luminance signal and the color signal. It goes without saying that the same effect can be obtained even if they are used for each, if the time difference is known in advance.

(Second Embodiment) In the magnetic recording / reproducing apparatus of the second embodiment, a reference signal is formed in synchronization with the input EDTV2 signal, and the luminance signal and the color signal are added with different polarities. As shown in FIG. 4, this device includes a reference signal generation circuit 30 for detecting a discrimination control signal of an input signal and generating a reference signal on the recording side, and a luminance signal obtained by separating the reference signal (positive polarity) from YC. To the adder 25, a polarity inverting circuit 31 for inverting the polarity of the reference signal, and a negative polarity reference signal with the polarity inverted.
And an adder 32 for adding to the C-separated color signal.
The other structure is the same as that of the device of the first embodiment (FIG. 1).

In this apparatus, when the reference signal generating circuit 30 detects the input of the identification control signal multiplexed on the 22nd line and the 285th line (FIG. 5A), as shown in the waveform diagram of FIG. , And outputs a rectangular pulse (FIG. 5B) to the signals of the 21st line and the 284th line which are the YC separated lines immediately before. This rectangular pulse is
After being added to the luminance signal by the adder 25 as the positive reference signal (FIG. 5C) and inverted by the polarity inversion circuit 31,
The negative reference signal (FIG. 5 (d)) is added to the color signal by the adder 32.

FIG. 6 is a timing chart showing the operation for detecting the deviation of the time axis during reproduction. The reference signal detection circuits 26 and 27 extract the above-mentioned reference signals (FIGS. 6 (a) and 6 (b)), shape the waveform, and generate pulses (FIGS. 6 (c) and 6 (d)). Then, the time difference detection circuit 28 outputs a pulse indicating the time difference between the luminance signal and the color signal by comparing the edges of both the pulses (FIG. 6).
(E)). The delay circuit 29 controls the delay time using this pulse, and matches the output timing of the luminance signal and the color signal.

In this case, the reference signal is added to the luminance signal and the chrominance signal once per field, so that the output timing is also compensated once per field. Is a period that is practically sufficient to compensate for the time difference between the luminance signal and the color signal.

In the apparatus of the second embodiment, the reference signal added during recording is canceled and the reference signal does not appear in the composite signal output when the output timing is adjusted. Therefore, this device is characterized by being compatible with conventional models.

(Third Embodiment) The magnetic recording / reproducing apparatus of the third embodiment uses the identification control signal of the EDTV2 signal as a reference signal.

As shown in FIG. 7, this apparatus includes a line detection circuit 33 for detecting the 22nd line and the 285th line through which an identification control signal is transmitted, and a luminance signal recording processing circuit and a color signal for the identification control signal. A switching circuit 34 for switching the connection so as to input to any of the recording processing circuits. The other structure is the same as that of the device of the first embodiment (FIG. 1).

In this magnetic recording / reproducing apparatus, when the 22nd line and the 285th line are detected from the EDTV2 signal inputted by the line detection circuit 33, the switching circuit 34 determines that the identification control signal of this line is the luminance signal recording processing circuit and the color. The connection is switched so as to be input to each of the signal recording processing circuits. For other lines, the output of the YC separation circuit 2 is connected so as to be directly input to each signal recording processing circuit. The signal input to each signal recording processing circuit is processed in the same manner as in the first embodiment and recorded on the magnetic tape 13.

As a result, the signals input to the luminance signal and color signal recording processing circuit are as shown in FIG.

At the time of reproduction, the above-mentioned identification control signal is used to compensate for the time difference between the luminance signal and the color signal at the time of reproduction by the same procedure as in the first or second embodiment. in this case,
As the reference signal, various signals included in the identification control signal,
That is, any of the color burst signal, the NRZ modulator, the fsc (color signal subcarrier) modulator, and the 4 / 7fsc sine wave unit can be used.

The output timing at this time is also compensated once per field, which is a period sufficient for practical use.

In the device of the third embodiment, the reference signal detection circuit 24 and the adder 25 shown in FIG. 1 are not required, so that the circuit configuration becomes simpler. Further, the tape recorded by the apparatus of the third embodiment is characterized in that it can be reproduced by a conventional magnetic recording / reproducing apparatus and has compatibility.

[0045]

As is apparent from the above description of the embodiments, the magnetic recording / reproducing apparatus of the present invention, when the luminance signal and the color signal are processed by different signal processing circuits, the luminance signal and the color in the reproduction output. It is possible to correct the time shift from the signal. Therefore, at the time of recording / reproducing the EDTV2 signal, even if the reinforcement signal is recorded by either the luminance signal processing circuit or the chrominance signal processing circuit, the reinforcement signal is not added to the wrong position at the time of decoding. Therefore, high-quality images can be obtained by sending the reproduction output of this device to a dedicated receiver.

The device of the present invention is based on the structure of a consumer magnetic recording / reproducing device such as a VHS system, and can support EDTV2 signals by only changing a part thereof.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a magnetic recording / reproducing apparatus according to a first embodiment of the present invention,

FIG. 2 is a waveform diagram illustrating a reference signal added in the magnetic recording / reproducing apparatus of the first embodiment,

FIG. 3 is a timing chart of a time difference detection operation in the magnetic recording / reproducing apparatus of the first embodiment,

FIG. 4 is a block diagram showing a configuration of a magnetic recording / reproducing apparatus according to a second embodiment of the present invention,

FIG. 5 is a waveform diagram illustrating a reference signal added by the magnetic recording / reproducing apparatus of the second embodiment.

FIG. 6 is a timing chart of a time difference detection operation in the magnetic recording / reproducing apparatus of the second embodiment,

FIG. 7 is a block diagram showing the configuration of a magnetic recording / reproducing apparatus according to a third embodiment of the present invention,

FIG. 8 is a waveform diagram illustrating a reference signal added by the magnetic recording / reproducing apparatus of the third embodiment.

FIG. 9 is a block diagram showing a configuration of a conventional magnetic recording / reproducing apparatus.

[Explanation of symbols]

 1 Input Terminal 2 YC Separation Circuit 3,17 Low-pass Filter 4 Emphasis Circuit 5 Clip Circuit 6 FM Modulation Circuit 7,16 High-pass Filter 8 Band-pass Filter 9 Low-pass Converter 10, 22, 25, 32 Adder 11 Recording Amplifier 12 Recording Head 13 Magnetic tape 14 Playback head 15 Playback amplifier 18 Limiter circuit 19 FM demodulation circuit 20 De-emphasis circuit 21 High frequency conversion circuit 23 Output terminals 24, 26, 27 Reference signal detection circuit 28 Time difference detection circuit 29 Delay circuit 30 Reference signal generation circuit 31 Polarity inversion circuit 33 Line detection circuit 34 Switching circuit

Claims (5)

[Claims] 1. A magnetic recording / reproducing method for processing a wide television signal in which a plurality of reinforcing signals for improving image quality and an identification signal for identifying a signal form are multiplexed by a luminance signal processing circuit and a color signal processing circuit. In the apparatus, reference signal adding means for adding a reference signal to the input signals of the luminance signal recording processing circuit and the color signal recording processing circuit, and the time of the reference signal at the output of the luminance signal reproduction processing circuit and the color signal reproduction processing circuit. A magnetic recording / reproducing apparatus comprising: a detection unit that detects a temporal shift, and a compensation unit that compensates the temporal shift and adjusts output timings of a luminance signal and a color signal. 2. The reference signal adding means forms the reference signal by using a signal included in the wide television signal, and adds the reference signal to an input signal of the luminance signal recording processing circuit or the color signal recording processing circuit. Claim 1 characterized by the above-mentioned.
3. The magnetic recording and reproducing device according to claim 1. 3. The reference signal adding means generates the reference signal in synchronization with an input wide television signal,
The magnetic recording / reproducing apparatus according to claim 1, wherein the magnetic recording / reproducing apparatus is added to an input signal of the luminance signal recording processing circuit and the color signal recording processing circuit. 4. The polarities of the reference signals added to the input signals of the luminance signal recording processing circuit and the color signal recording processing circuit by the reference signal adding means are different from each other. Magnetic recording / reproducing device. 5. A magnetic recording / reproducing method for processing a wide television signal in which a plurality of reinforcing signals for improving image quality and an identification signal for identifying a signal form are multiplexed by a luminance signal processing circuit and a color signal processing circuit. In the apparatus, an identification signal input means for inputting the identification signal to both the luminance signal recording processing circuit and the color signal processing circuit, and a temporal change of the identification signal in the output signals of the luminance signal reproduction processing circuit and the color signal reproduction processing circuit. A magnetic recording / reproducing apparatus comprising: a detection unit that detects a shift and a compensation unit that compensates the time shift and adjusts the output timing of a luminance signal and a color signal.