JPH0378395A - Magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To reduce a noise contained in a chrominance signal in a dark picture, and to obtain the picture easy to see in visibility by changing the saturation of a chrominance signal according to the size of a luminance signal. CONSTITUTION:In a synchronizing separation circuit 7, only a horizontal synchronizing signal part of a regenerative luminance signal is extracted, and by delaying it by definite time by a delay circuit 8, a burst gate pulse (c) is generated, and this burst gate pulse (c) is inputted to a CGC (chrominance signal saturation control) circuit 9. The CGC circuit 9 operates during a period (t) when the burst gate pulse (c) is Hi-level, and it does not operate at the time of Lo- level. Accordingly, the amplitude of color burst signal B among the chrominance signal sent to the CGC circuit 9 and shown in a figure (d) is kept constant, and only the chrominance signal part C is changed by the amplitude of the luminance signal, and the color saturation is changed as shown in a figure (e) Thus, the noise of the chrominance signal at the time of the low level of the luminance signal can be reduced, and the picture easy to see can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording/reproducing device, and more particularly to a processing circuit for reproduced color signals.

[Prior Art] FIG. 3 is a block diagram showing the configuration of a color signal processing circuit in a conventional magnetic recording/reproducing device.
) is a magnetic head for reproducing video signals, (2) is a low-pass filter (hereinafter referred to as LPF) that extracts only color signals, and (3) is an ACC circuit for keeping the amplitude of the color burst signal constant.

(0 is a frequency converter for converting the low frequency converted color signal to a high frequency.

Next, the operation of the above configuration will be explained.

The reproduction signal detected by the magnetic head (1) is L P
F (2) and only the color signal components are extracted. The color signal component is then sent to the ACC circuit (3), corrected so that the amplitude of the color burst signal is constant, and then sent to the frequency converter (0).

In general, one color value in magnetic recording and reproducing devices is 600K.
Because it is converted to a low frequency around Hz and recorded,
During reproduction, one color value code is reproduced by converting to a high frequency using a frequency converter (0).

[Problem to be Solved by the Invention 1] Since the conventional magnetic recording and reproducing apparatus is configured as described above, the ratio between the amplitude of the reproduced color signal and the color burst signal, that is, the saturation of one color is Therefore, when the amplitude of the luminance signal is small, that is, on a dark screen, there is a problem that the noise component included in the color signal makes the image visually difficult to see.

This invention has been made to solve the above-mentioned problems, and aims to provide a magnetic recording and reproducing device that can reduce the visual noise of the color signal when the amplitude of the luminance signal is small. purpose.

[Means for Solving the Problems] A magnetic recording and reproducing device according to the present invention is characterized in that it is configured to detect the magnitude of a luminance signal and control the saturation degree of a color signal based on the magnitude. .

[Function] According to the present invention, the saturation level of the color signal is changed using the control signal obtained by detecting the magnitude of the luminance signal, thereby reducing noise in the color signal when the level of the luminance signal is low. be able to.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the configuration of a color signal processing circuit in a magnetic recording/reproducing apparatus according to an embodiment of the present invention.

In Figure 1, (5) is a clamp circuit for keeping the DC potential of the luminance signal constant, (8) is a luminance signal level detection circuit for detecting the amplitude of the luminance signal, and (7) is synchronized from the luminance signal. This is a synchronous separation circuit that extracts only the signal.

(8) is a delay circuit that delays the synchronization signal to create a burst gate pulse, and (9) is a color signal saturation control circuit that changes the saturation level of the color signal (hereinafter referred to as "color signal saturation control circuit").

Since the other configurations are the same as the conventional example shown in FIG. 3, the same reference numerals are given to the corresponding parts and detailed explanation thereof will be omitted.

Next, the operation of the above configuration will be explained.

The reproduced luminance signal is sent to the clamp circuit (5),
As shown in Figure 2 (a), the pedestal level (PL)
After being corrected so that it has a constant DC potential, it is sent to a luminance signal level detection circuit (8).

Here, Fig. 2 (b) changes in proportion to the amplitude of the luminance signal.
), and its control voltage (b)
is sent to the 000 circuit (9).

On the other hand, in the synchronization separation circuit (7), only the horizontal synchronization signal portion is extracted from the reproduced luminance signal and delayed by a delay circuit (8) for a certain period of time, thereby producing a burst signal as shown in FIG. 2(C). A gate pulse is created, and this burst gate pulse (c) is input to the 000 circuit (8).

This 000 circuit (9) is the burst gate pulse (C
) operates during the period (1) when “H1” level, and “L”
It does not work when it is at "o" level.

Therefore, Fig. 2 (
Among the color signals shown in d), the color burst signal (
The amplitude of B) is kept constant, and only the color signal part (C) changes depending on the amplitude of the luminance signal.

As shown in FIG. 2 (@), the color saturation changes.

Note that in the above embodiment, the case where the color burst signal is kept constant and the amplitude of the color signal is varied is explained.
Even if the color signal is kept constant and only the color burst signal is changed, the same effect as in the above embodiment can be obtained.

[Effects of the Invention] As described above, according to the present invention, the saturation degree of the color signal is changed depending on the magnitude of the luminance signal, so that when the amplitude of the luminance signal is small, that is, the color on a dark screen is It can reduce the noise contained in the signal,
This has the effect of providing an image that is visually easy to see.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a color signal processing circuit in a magnetic recording/reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a signal waveform diagram for explaining the operation of the embodiment, and FIG. 3 is a conventional FIG. 2 is a block diagram showing the configuration of a color signal processing circuit in the magnetic recording/reproducing device. (5)...clamp circuit, (6)...luminance signal level detection circuit, (9)...000 circuit. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A luminance signal level detection circuit that detects the magnitude of a luminance signal in a video signal, and a color signal saturation control circuit that changes the saturation of a color signal depending on the magnitude of the detected luminance signal. Features of magnetic recording and reproducing device.