KR200194826Y1 - Apparatus for automatically switching the operation mode in a video cassette recorder - Google Patents

Abstract

The present invention relates to an operation mode automatic switching device of a video cassette recorder for automatically switching to an operation mode corresponding to a connection state of a video cassette recorder. The present invention provides an operation mode of a video cassette recorder when a television is connected to an image output terminal and an audio output terminal. An apparatus for automatically switching the signal, comprising: an image signal processor for processing and providing an image signal output from an image output terminal; An audio signal processor configured to process and provide an audio signal output from the audio output terminal; A first buffer which buffers and provides a video signal provided from the video signal processor; A second buffer which buffers and provides an audio signal provided from an audio signal processor; Compare the voltage of the DC level of the image signal provided by the image signal processing unit with the voltage of the DC level of the image signal provided by the first buffer to compare the video output terminal connection between the video cassette recorder and the television. An image output terminal detector for detecting and providing an image output terminal connection detection signal; Compare the voltage of the DC level of the audio signal provided by the audio signal processing unit with the voltage of the DC level of the audio signal provided by the second buffer to compare the audio output terminal connection between the video cassette recorder and the television. An audio output terminal detector for detecting and providing an audio output terminal connection detection signal; When the video output terminal connection detection signal and the audio output terminal connection detection signal are provided by the video output terminal detection unit and the audio output terminal detection unit, the operation mode of the video cassette recorder is switched to the television mode, and the video output terminal detection unit and the audio output terminal detection unit And a micom for automatically switching the operation mode of the video cassette recorder to the video cassette recorder mode when the output terminal connection detection signal and the audio output terminal connection detection signal are not provided.

Description

Video cassette recorder operation mode automatic switching device

The present invention relates to an operation mode switching device of a video cassette recorder, and more particularly, to an operation mode automatic switching device of a video cassette recorder which automatically switches to an operation mode corresponding to a connection state of a video cassette recorder.

In general, a video cassette recorder has a recording function of recording a composite video signal applied from a tuner tuned to a desired channel by a broadcast signal received through an antenna, and reproducing the composite video signal recorded on the magnetic tape. It has a playback function to display on the monitor.

The operation mode of a video cassette recorder having such a function is divided into a TV mode (hereinafter referred to as a TV) mode and a video cassette recorder mode. In other words, the TV mode does not use a video cassette recorder and does not use RF (RF :). Radio Frequency) This mode is used to select and watch broadcast signal only through TV by providing broadcast signal directly through cable output terminal. In video cassette recorder mode, watch playback screen after adjusting TV channel to 3 channel or 4 channel. This mode is used when you want to use the video cassette recorder.

In addition, when a TV and a video cassette recorder having a conversion key in the TV or video cassette recorder switching mode as described above are used together, an external antenna for receiving broadcast signals is typically connected to the TV through the video cassette recorder.

In such a device, if the mode of the video cassette recorder is set to the TV mode, or if the video cassette recorder is OFF, the video cassette recorder is disconnected from the TV, and the desired TV channel is selected in the TV tuner. .

On the other hand, if the user sets the video cassette recorder mode or the video cassette recorder is ON (the video cassette recorder mode is set automatically at this time), the playback signal or the broadcast signal selected in the video cassette recorder tuner It is modulated with the frequency of channel 3 or 4 and output. The modulated signal is then transmitted to the TV together with the broadcast signal received from the external antenna.

That is, since the modulated signal transmitted from the video cassette recorder to the TV is generally stronger than the broadcast signal transmitted through the antenna, strong interference occurs in a relatively weak broadcast signal, that is, correlated with the RF cable connection state between the video cassette recorder and the TV. As the video cassette recorder operates without being switched to the video cassette recorder mode, the viewer has difficulty in watching a TV program received through a channel directly selected by the TV tuner.

The present invention has been made in view of the above-described problem, and an object of the present invention is to automatically switch to a TV or video cassette recorder mode corresponding to the RF cable connection state between the video cassette recorder and the TV, so that the video cassette recorder mode is Disclosed is an operating mode automatic switching device of a video cassette recorder for removing interference from TV viewing to facilitate viewing.

A feature of the present invention for achieving the above object is an apparatus for automatically switching the operation mode of a video cassette recorder when a television is connected to an image output terminal and an audio output terminal, which processes and provides an image signal output from the image output terminal. An image signal processor; An audio signal processor configured to process and provide an audio signal output from the audio output terminal; A first buffer which buffers and provides a video signal provided from the video signal processor; A second buffer which buffers and provides an audio signal provided from the audio signal processor; The voltage between the DC level of the video signal provided by the video signal processor and the DC level of the DC signal of the video signal provided by the first buffer is compared to provide an image between the video cassette recorder and the television. An image output terminal detector for detecting an output terminal connection and providing an image output terminal connection detection signal; The voltage between the DC level of the audio signal provided by the audio signal processor and the voltage of the DC level of the audio signal provided by the second buffer is compared with the audio between the video cassette recorder and the television. An audio output terminal detector for detecting an output terminal connection and providing an audio output terminal connection detection signal; And when the video output terminal connection detection signal and the audio output terminal connection detection signal are provided from the video output terminal detection unit and the audio output terminal detection unit, the operation mode of the video cassette recorder is switched to a television mode, and the video output terminal detection unit And a micom for automatically switching an operation mode of the video cassette recorder to a video cassette recorder mode when the video output terminal connection detection signal and the audio output terminal connection detection signal are not provided by the audio output terminal detection unit.

The above object and various advantages of the present invention will become more apparent from the preferred embodiments of the invention described below with reference to the accompanying drawings by those skilled in the art.

1 is a block diagram showing the configuration of an automatic operation mode switching apparatus of a video cassette recorder according to a preferred embodiment of the present invention;

<Description of the code | symbol about the principal part of drawing>

10: image signal processing unit 20: audio signal processing unit

30, 40: Buffer 50: Video output terminal detector

60: audio output terminal detector 70: microcomputer

Hereinafter, with reference to the accompanying drawings will be described in detail the operation of the preferred embodiment according to the present invention.

1 is a block diagram showing a configuration of an automatic operation mode switching apparatus of a video cassette recorder according to the present invention, an image signal processing unit 10 for processing and providing an input video signal and an audio signal for processing an input audio signal The first buffer 30 buffering the video signal provided from the signal processor 20, the video signal processor 10, and the second buffer 40 buffering the video signal provided from the audio signal processor 20. ), Comparing the video signal provided from the video signal processing unit 10 with the video signal provided from the first buffer 30 to detect the presence or absence of a video output terminal connection signal between the video cassette recorder and the television to detect a video output terminal connection detection signal. The audio signal provided from the image output terminal detector 50 and the audio signal processor 20 provided is compared with the audio signal provided from the second buffer 40. Image output terminal detection section 60, image output terminal detection section 50, and audio output terminal detection section 60 which detect audio output terminal connection between the video cassette recorder and a television and provide an audio output terminal connection detection signal. And a microcomputer 70 for providing a television with a control signal corresponding to the presence or absence of the terminal connection detection signal and the audio output terminal connection detection signal.

The detailed description of the operation of the automatic operation mode switching apparatus of the video cassette recorder according to the present invention configured as described above is as follows.

The first buffer 30 buffers the video signal provided from the video signal processor 10 to the video output terminal detector 50 and the television, and the second buffer 40 is provided from the audio signal processor 20. Since the audio signal is buffered and provided to the audio output terminal detector 60 and the television, detailed operation descriptions of the first buffer and the second buffer will be omitted since those skilled in the art can easily understand.

In this case, the image output terminal detector 50 may provide a voltage for the DC level of the image signal buffered by the first buffer 30 and the DC of the image signal provided by the image signal processor 10. The voltages for the levels are compared and a logic signal for the comparison result is provided to the microcomputer 70.

In other words. The voltage of the DC level of the image signal provided by the image signal processor 10 is provided to the non-inverting (+) input terminal, and the voltage of the DC level of the image signal provided from the first buffer 30 is provided. The voltage is provided to the inverting (-) input terminal. When the video output terminal is connected between the video cassette recorder and the television, the impedance of the video signal is applied to the DC level of the video signal provided from the first buffer 30. Since the voltage is low, the image output terminal detector 50 may output a logic signal for connecting the image output terminal, that is, a high level logic signal when the voltage at the non-inverting (+) input terminal is higher than the voltage at the inverting (−) input terminal. )

On the other hand, the audio output terminal detector 60 is provided with a voltage for the DC level of the audio signal provided by the audio signal processor 20 provided as a non-inverting (+) input terminal and a second input terminal as an inverting (-) input terminal. By comparing the voltage of the DC level of the audio signal provided from the buffer 40, the voltage of the DC level of the audio signal provided from the second buffer 40 is compared with the audio signal processor 20. If the voltage is lower than the DC level of the provided audio signal, the logic signal for the audio output terminal connection, that is, the high level logic signal is provided to the microcomputer 70.

At this time, those skilled in the art that the logic signal provided from the image output terminal detector 50 and the audio output terminal detector 60 to the microcomputer 70 may be set differently in system design. Will understand.

Therefore, when the high level logic signal is supplied from the video output terminal detector 50 and the audio output terminal detector 60, the microcomputer 70 determines that the video output terminal is connected between the video cassette recorder and the television. The video cassette recorder is operated in the video cassette recorder mode by determining that there is no audio output terminal connected between the video cassette recorder and the television when a low level logic signal is provided.

As described above, the operation mode automatic switching device of the video cassette recorder according to the present invention detects the RF cable condition between the video cassette recorder and the television, so that the RF cable is connected between the video cassette recorder and the television. When connected, it automatically switches to the television mode, and when there is no RF cable between the video cassette recorder and the television, it automatically switches to the video cassette recorder mode, which makes it easy to watch TV even in the video cassette recorder mode. have.

Although the present invention has been shown and described with respect to certain preferred embodiments, it will be apparent to those skilled in the art that various modifications, changes and omissions can be made without departing from the spirit and scope of the present invention.

Claims (1)

An apparatus for automatically switching the operation mode of a video cassette recorder when a television is connected to an image output terminal and an audio output terminal. An image signal processor configured to process and provide an image signal output from the image output terminal; An audio signal processor configured to process and provide an audio signal output from the audio output terminal; A first buffer which buffers and provides a video signal provided from the video signal processor; A second buffer which buffers and provides an audio signal provided from the audio signal processor; The voltage between the DC level of the video signal provided by the video signal processor and the DC level of the DC signal of the video signal provided by the first buffer is compared to provide an image between the video cassette recorder and the television. An image output terminal detector for detecting an output terminal connection and providing an image output terminal connection detection signal; The voltage between the DC level of the audio signal provided by the audio signal processor and the voltage of the DC level of the audio signal provided by the second buffer is compared with the audio between the video cassette recorder and the television. An audio output terminal detector for detecting an output terminal connection and providing an audio output terminal connection detection signal; When the video output terminal connection detection signal and the audio output terminal connection detection signal are provided by the video output terminal detection unit and the audio output terminal detection unit, the operation mode of the video cassette recorder is switched to a television mode, and the video output terminal detection unit Operation of a video cassette recorder including a micom which automatically switches an operation mode of the video cassette recorder to a video cassette recorder mode when the video output terminal connection detection signal and the audio output terminal connection detection signal are not provided by the audio output terminal detection unit. Mode switching device.