JPH05109185A - Magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To reduce a color smear easy to be generated when a video signal regenerated at the magnetic recording/reproducing device is monitored. CONSTITUTION:A chromafilter 7 for extracting color signal ingredients is converted into a color subcarrier wave signal at a frequency converter 8 and inputted to an equalizer 10 via a chroma deemphasis circuit 9. The phase shift of the choma signal generated by the chomafilter 7 is compensated by the egualizer 10 and the wide band of the chroma signal is oftained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a magnetic recording / reproducing apparatus capable of obtaining an image with less color fringing by extracting a chroma signal by using a filter having a wider band than ever before. Is.

[0002]

2. Description of the Related Art A video signal reproduced by a magnetic recording / reproducing apparatus is often extracted by a filter having a relatively narrow band since a chroma signal component is converted into a low frequency band. FIG. 3 shows frequency allocation in the case of, for example, an 8 mm magnetic recording device. The chroma signal C is frequency-converted to a low frequency (760 KHZ), and the luminance signal is frequency-modulated in the high frequency band. Is recorded.
A tracking pilot signal ATF and a frequency-modulated audio signal AFM are arranged on both sides of the chroma signal C. Therefore, when reproducing such a signal to obtain a chroma signal, a filter having a relatively narrow band is used so that the pilot signal and the voice signal are not lost, and the high frequency component of the chroma signal is used. However, there is a problem that color blur easily occurs on the reproduction screen due to the loss of the color.

[0003]

SUMMARY OF THE INVENTION In order to reduce such problems, the present invention uses a filter having a wider band than before, and also provides a chroma signal generated by sharpening the cut point and widening the band of the filter. It is configured so that the phase around is compensated by using an equalizer. Further, the increase in the delay time of the chroma signal caused by using the filter of the wide band is controlled by the digital delay circuit provided in the luminance signal system so that the phase delay does not occur.

[0004]

[Function] By increasing the pass frequency band of the filter for extracting the chroma signal, the high frequency component of the chroma signal becomes a sufficient level, and the phase rotation caused by that is eliminated by the equalizer. It is possible to reduce color bleeding that tends to occur.

[0005]

FIG. 1 is a block diagram showing an embodiment of the present invention. In this figure, 1 is a magnetic tape on which a video signal is recorded, 2 is a reproducing magnetic head, and 3 is an RF amplifier. The video signal reproduced by the RF amplifier 3 has its luminance signal component separated by a high-pass filter 4, and is converted into a video signal by a demodulator 5. Then, a digital delay circuit 6 described later delays the signal for a predetermined time. The chroma signal component output from the RF amplifier 3 is extracted by the chroma filter 7 and converted by the frequency converter 8 into the color subcarrier frequency (3.58 MHZ). The chroma de-emphasis circuit 9 suppresses a wide range of frequency components of the color sub-carrier, and the color sub-carrier is supplied to the equalizer 10. Reference numeral 11 denotes an adder circuit for synthesizing the luminance signal and the color subcarrier signal to obtain a composite video signal. In addition,
Since the extraction of the pilot signal and the extraction of the voice fm signal are not directly related to the present invention, the description thereof will be omitted.

In the circuit of the present invention, the chroma filter 7 has a wide band characteristic so that the high frequency component can be sufficiently extracted in consideration of the frequency band of the color signal performed at the time of recording, and the cut-off characteristic is rapidly completed. I have to. Therefore, the output of the chroma filter 7 increases in phase around, especially at a frequency near the cutoff of the filter, causing a phase delay. Therefore, in the magnetic recording / reproducing apparatus of the present invention, after the chroma signal having the phase rotation is converted into the color subcarrier, the equalizer 10 is provided to compensate. That is, as shown by the solid line in FIG. 2, when the chroma filter of the present invention is used, the delay amount of the signal deviated from the center frequency of the color subcarrier tends to increase, and this delay amount is shown by the dotted line in FIG. It is designed so as to be compensated by the delay characteristic of the equalizer 10 as shown by.

Therefore, the signal deterioration caused by using the broadband chroma filter 7 is eliminated. However, in such a circuit, the total delay amount is significantly increased as compared with the delay amount caused by the conventional chroma signal processing, and the phase error with the luminance signal is increased.
Therefore, in the case of the present invention, the above-mentioned digital delay circuit 6 is provided in the circuit of the luminance signal system to eliminate the phase difference from the chroma signal. This digital delay circuit is A /
D converter 6a, shift register 6b, D / A converter 6c
And a large delay amount that cannot be obtained by the conventional delay circuit is given to the luminance signal.

In the above embodiment, the low-pass converted chroma signal is converted to a high-pass frequency, and then an equalizer for flattening the phase is used for compensation. However, a chroma for extracting the low-pass converted signal is used. An equalizer may be arranged after the filter 7 so that the phase becomes flat.

[0009]

As described above, the present invention broadens the band of the filter for extracting the chroma signal, combines the equalizer for flattening the phase, and obtains a large delay amount in the luminance signal system. By providing the above, it is possible to improve the horizontal color blurring on the monitor screen and prevent ringing that tends to occur at the contour portion.

[Brief description of drawings]

FIG. 1 is a block diagram of a reproducing system circuit in a magnetic recording / reproducing apparatus of the present invention.

FIG. 2 is an explanatory diagram of a phase delay of a color signal component and a delay amount by an equalizer.

FIG. 3 is a diagram showing frequency allocation when recording a video signal.

[Explanation of symbols]

 3 RF amplifier 10 7 Chroma filter 8 Frequency converter 9 De-emphasis circuit 10 Equalizer

Claims (1)

[Claims] 1. In a magnetic recording / reproducing apparatus for separating a video signal into a luminance signal and a chroma signal and recording them on a magnetic recording medium, a filter having a high band in a circuit of a chroma signal processing system and an average phase. And an analog-to-digital converter in the circuit of the luminance signal processing system, a shift register for delaying by the delay time in the chroma signal processing system, and a digital-to-analog converter. Characteristic magnetic recording / reproducing apparatus.