JPH10210418A - Magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording and reproducing device, in which the circuit configuration is simplified by reducing a mute circuit and input output control signals are reduced in a microcomputer. SOLUTION: A microcomputer 205 outputs a channel (CH)-switching signal to a tuner selection station circuit 201 to switch a CH. Then the microcomputer 205 outputs a Clock signal to an on-screen display(OSD) circuit 203. When the Clock signal is inputted, the OSD circuit 203 generates an internal synchronizing signal and outputs it from an output terminal 206. While the internal synchronization signal is outputted, a video signal from a video signal processing circuit 202 is not outputted from the output terminal 206. Even when a noise signal, such as video buzz generated in the tuner selection station circuit 201, reaches the OSD circuit 203 via a video signal processing circuit 202, the OSD circuit 203 generates the internal synchronization signal.

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 having a video signal processing circuit, a tuner selection circuit controlled by a microcomputer, and an on-screen display circuit (hereinafter referred to as an OSD circuit).

[0002]

2. Description of the Related Art In recent years, in a magnetic recording / reproducing apparatus, a video signal output from a tuner selection circuit causes a video buzz in a TV receiver due to switching noise when a channel (hereinafter, referred to as CH) is switched. Because it occurs, C
At the time of H switching, an external video mute is performed by the microcomputer for the tuner selection circuit. Also, video muting is performed by a video muting circuit under control of the microcomputer, even for video output at unintended and unnecessary timing.

Hereinafter, a conventional magnetic recording / reproducing apparatus will be described with reference to the drawings. FIG. 2 is a block diagram showing a configuration of a conventional magnetic recording / reproducing apparatus. In FIG. 2, reference numeral 101 denotes a tuner selection circuit for receiving a television signal from an antenna (not shown) and demodulating the television signal into a composite video signal;
Is a video signal processing circuit that performs various processing on the video signal demodulated by the tuner tuning circuit 101, 103 is an OSD circuit that displays a video signal output from the video signal processing circuit 102,
Reference numeral 104 denotes a first mute circuit for muting the output of the video signal at unnecessary timing, and reference numeral 106 denotes a second operation for temporarily muting the output signal in order to prevent buzz at the time of CH switching in the tuner selection circuit 101. A mute circuit 107 is an output terminal.

The operation of the conventional magnetic recording / reproducing apparatus configured as described above will be described below.

[0005] A signal from an antenna (not shown) is received and demodulated by a tuner tuning circuit 101, and various video signal processes are performed by a video signal processing circuit 102. The video signal from the video signal processing circuit 102 is transmitted to the OSD circuit 103 and the first
Is output to the output terminal 107 through the mute circuit 104.

[0006] In order to prevent image buzz on the television receiver side due to noise at the time of CH switching, O
The clock signal is input from the SD circuit 103 to the microcomputer 105, and based on the clock signal, the microcomputer 105
The second mute circuit 106 performs a mute operation on the tuner selection circuit 101 in response to the Mute1 signal output from.

In order to mute video output at unnecessary timing, Mute output from the microcomputer 105 is used.
With the two signals, the first mute circuit 104 operates, and video mute is performed.

[0008]

However, in the above-described conventional configuration, two components, such as the first and second mute circuits, are required to prevent image buzz, so that the circuit configuration becomes complicated and the cost is reduced. There was a problem that leads to up.

The present invention solves the above-mentioned conventional problems, and provides a magnetic recording / reproducing apparatus which can simplify a circuit configuration and reduce input / output control signals in a microcomputer by reducing mute circuits. Aim.

[0010]

SUMMARY OF THE INVENTION In order to achieve this object, the present invention provides a tuner tuning circuit for receiving and demodulating a television signal, and a video signal for performing various signal processing on a video signal from the tuner tuning circuit. A signal processing circuit, an OSD circuit that outputs the video signal from the video signal processing circuit as it is or generates and outputs an internal synchronization signal, and outputs a channel switching signal to the tuner selection circuit and outputs the signal to the OSD circuit. A microcomputer that outputs a control signal for switching between outputting the video signal from the video signal processing circuit as it is or generating and outputting the internal synchronization signal.

According to the above configuration, by reducing the number of mute circuits, it is possible to provide a magnetic recording / reproducing apparatus which can simplify the circuit configuration and reduce input / output control signals in the microcomputer.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a tuner tuning circuit for receiving and demodulating a television signal, and a video signal for performing various signal processing on a video signal from the tuner tuning circuit. A processing circuit, an OSD circuit that outputs the video signal from the video signal processing circuit as it is or generates and outputs an internal synchronization signal, and outputs a channel switching signal to the tuner selection circuit and A microcomputer that outputs a control signal that switches between outputting the video signal from the video signal processing circuit as it is or generating and outputting the internal synchronization signal, without changing the current circuit configuration. The video mute circuit of the tuner selection circuit, the video mute circuit of the video signal processing circuit, and the control signal from the microcomputer that controls these circuits. It is possible to delete. Also, with respect to the mute time and the mute operation due to the variation of the circuit, it is possible to stably perform the same effect as the mute operation at an arbitrary timing and time.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 is a block diagram showing an embodiment of a magnetic recording / reproducing apparatus according to the present invention. In FIG. 1, reference numeral 201 denotes a tuner tuning circuit that receives and demodulates a television signal from an antenna (not shown); 202, a video signal processing circuit that performs various processes on a video signal from the tuner tuning circuit 201; An OSD circuit that passes the video signal from the video signal processing circuit 202 as it is or outputs an internal synchronization signal (black back or blue back). 205 is a microcomputer that controls the OSD circuit 203 based on a Clock signal from the tuner tuning circuit 201. Yes, the channel switching of the tuner tuning circuit 201 is controlled by the CH signal. An output terminal 206 outputs a video signal output from the OSD circuit 203 to the outside.

The operation of the magnetic recording / reproducing apparatus of the present embodiment configured as described above will be described below.

A television signal from an antenna (not shown) is received and demodulated by a tuner selection circuit 201,
The video signal processing circuit 202 performs various video signal processing. The video signal output from the video signal processing circuit 202 is output from the output terminal 206 to the outside via the OSD circuit 203.

Here, when a CH switching command is input from the outside, the microcomputer 205 outputs a CH switching signal to the tuner selection circuit 201 to switch channels. At the same time, the microcomputer 205 sends the OSD circuit 203
When the Clock signal is input, the OSD circuit 203 generates an internal synchronization signal and outputs it from the output terminal 206. While the internal synchronization signal is being output, the video signal from the video signal processing circuit 202 is not output from the output terminal 206. Therefore, even if a noise signal such as a video buzz generated by the tuner tuning circuit 201 reaches the OSD circuit 203 via the video signal processing circuit 202, the OSD circuit 203 should generate an internal synchronization signal. Therefore, no noise signal appears on the TV screen.

As described above, according to the present embodiment, it is possible to prevent a noise signal such as video buzz from being output on a TV screen with a simple configuration.

[0018]

As described above, the present invention can reduce the two mute circuits required conventionally and the signal from the microcomputer for controlling the two mute circuits. This is an excellent effect that the noise signal can be prevented from being output on the TV screen.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing a configuration of a conventional magnetic recording / reproducing apparatus.

[Explanation of symbols]

 201 Tuner Tuning Circuit 202 Video Signal Processing Circuit 203 OSD Circuit 205 Microcomputer

Claims (1)

[Claims] 1. A tuner selection circuit for receiving and demodulating a television signal, a video signal processing circuit for performing various signal processing on a video signal from the tuner selection circuit, and a video signal from the video signal processing circuit. An OSD circuit that outputs as it is or outputs an internal synchronization signal, and a channel switching signal that is output to the tuner selection circuit and a video signal from the video signal processing circuit that is output to the OSD circuit as it is A magnetic recording / reproducing apparatus comprising: a microcomputer for outputting a control signal for switching between generating and outputting the internal synchronization signal.