KR19980058821A - Noise Canceling Device for HI-FI Video Cassette Recorder - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise canceling device for a hi-fi video cassette recorder. When the broadcast signal provided from the tuner is a PAL method, the holder is operated by an operation signal from the detector and is provided from the ultra short amplifier. The signal is held at a predetermined frequency (for example, 32.4 MHz), filtered by the filtering unit, demodulated by the IF demodulation unit to an intermediate frequency, and outputs an image signal and an audio signal, wherein the first signal is switched by the switching signal from the detector. As the switching unit and the second switching unit are turned off, the band pass filtering according to the broadcasting method is performed, respectively, so that the noise generated between the acoustic signals is removed to output a sound signal having improved sound quality.

Description

Noise Canceling Device for HI-FI Video Cassette Recorder

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a hi-fi video cassette recorder, and more particularly, to a noise canceling device of a hi-fi video cassette recorder suitable for removing noise due to interference generated during voice processing of a hi-fi video cassette recorder. It is about.

In general, in a conventional video cassette recorder, a Hi-Fi video cassette recorder additionally adds an audio dedicated rotating head, whereas a video signal is a rotating head and an audio signal is recorded and reproduced on a video tape as a fixed head. And a video cassette recorder which frequency-modulates the audio signal, records the deep portion of the video tape, and reproduces the best sound quality by superimposing and recording the video signal thereon.

FIG. 2 is a schematic block diagram of a sound processing apparatus of a conventional hi-fi video cassette recorder, and includes a filtering unit 40 for filtering a broadcast signal provided from a tuner, and a broadcast signal filtered through the filtering unit 40. The first band pass filter for filtering an acoustic signal in a broadcast signal according to an IF (Intemediate Frequency) demodulator 60 and a broadcast method (for example, PAL method and SECAM method) that demodulates an intermediate frequency. 50 and a second band pass filter 70.

2, the broadcast signal provided from the tuner is filtered through the filter 40, and the broadcast signal filtered through the filter 40 is filtered through the IF demodulator 60. The video signal VIDEO and the sound signals STEREO 1 and STEREO 2 are output.

On the other hand, when the sound signal in the broadcast signal is a PAL method, one of the outputs of the sound signal is bandpass filtered at 5.74 MHz in the first bandpass filter 50, and the other is the second bandpass filter ( Band pass filtered to 5.5 MHz within 70).

In addition, when the sound signal in the broadcast signal is the SECAM method, one of the outputs of the sound signal is band pass filtered at 6.25 MHz in the first band pass filter 50, and the other is the second band pass filter ( Band pass filtered to 6.5 MHz within 70).

However, there is a problem in that noise is generated by affecting 5.5 MHz in the first band pass filter 50 and 5.74 MHz portions of the second band pass filter 70 during band pass filtering of the PAL acoustic signal.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to remove noise of a hi-fi video cassette recorder capable of removing noise by selectively performing band pass filtering according to a broadcasting method. It is to provide a device.

In order to achieve the above object, the noise removing device of the HI-FI video cassette recorder of the present invention filters a broadcast signal provided from a tuner through a filter means, and uses an IF demodulation means to generate an intermediate frequency. A device for outputting a video signal and an audio signal, comprising: amplifying means for amplifying a broadcast signal provided from the tuner to a predetermined level; Discriminating means for discriminating a broadcast method of the broadcast signal provided from the tuner and generating an operation signal and a switching signal according to the determined broadcast method; Holding means for holding the broadcast signal amplified by the amplifying means by a drive signal from the discriminating means at a predetermined frequency; And band pass filter means for selectively performing band pass filtering according to the respective broadcasting schemes based on the switching signal from the discriminating means.

1 is a schematic block diagram of an apparatus for removing noise of a hi-fi video cassette recorder according to a preferred embodiment of the present invention.

2 is a schematic block diagram of a sound processing apparatus of a conventional hi-fi video cassette recorder according to the related art;

Explanation of symbols on the main parts of the drawing

10: ultra short amplifier 20: detector

30: holder 40: filtering unit

50,70: band pass filter 60: IF demodulation unit

80,90: switching part

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic block diagram of an apparatus for removing noise of a hi-fi video cassette recorder according to an exemplary embodiment of the present invention. The first stage amplifying unit 10, the detecting unit 20, the holder 30, the filtering unit 40, The IF demodulator 60, the first band pass filter 50, the second band pass filter 70, the first switching unit 80 and the second switching unit 90.

On the other hand, the filtering unit 40, the IF demodulator 60, the first band pass filter 50 and the second band pass filter 70 in the constituent members of the noise removing device of the hi-fi video cassette recorder according to the present invention are described above. Since the constituent members of the sound processing apparatus of the conventional conventional hi-fi video cassette recorder perform substantially the same function, the description herein will be omitted in order to avoid overlapping substrates.

Therefore, the constituent members of the present invention differ from the constituent members of the conventional sound processing apparatus by using the ultra short amplifier 10, the detector 20, the holder 30, the first switch 80, and the second switch. As 90, the following describes the operation of these constituent members.

First, the ultra-short amplifier 10 amplifies the broadcast signal provided from the tuner to a predetermined level, and the detector 20 detects the broadcast signal to determine the broadcast method. When the broadcast method is the PAL method, the holder 30 An operation signal for operating the control signal and a switching signal for turning off the first switching unit 80 and the second switching unit 90 are generated.

In addition, the holder 30 is operated by the operation signal from the detector 20 to hold the broadcast signal amplified to a predetermined level through the ultra-short amplifier 10 at a predetermined frequency (for example, 32.4 MHz) to filter 40 ), And the first switching unit 80 and the second switching unit 90 are switched by a switching signal from the detection unit 20.

An operation process of the noise canceling apparatus of the hi-fi video cassette recorder according to the present invention configured as described above will be described in detail.

First, a broadcast signal is provided from the tuner, amplified to a predetermined level through the ultra-short amplifier 10, and then provided to the filtering unit 40. In this case, as a result of the detection of the broadcast signal through the detector 20, the broadcast method is PAL. In the case of the method, the detector 20 generates a driving signal for driving the holder 30, and generates a switching signal for turning off the first switching unit 80 and the second switching unit 90.

Therefore, the holder 30 is driven by the drive signal from the detector 20, and the broadcast signal amplified to a predetermined level through the ultra-short amplification unit 10 is held at a predetermined frequency (for example, 32.4 MHz) to filter. Next, the filter 40 is filtered through the filtering unit 40 and then provided to the IF demodulator 60.

Next, after demodulating the intermediate frequency through the IF demodulator 60, the video signal VIDEO and the sound signals STEREO 1 and STEREO 2 are output.

At this time, the first switching unit 80 and the second switching unit 90 are switched off by the switching signal from the detection unit 20, so that the PAL type sound signal is 5.74 MHz of the first band pass filter 50. And band pass filtering only by 5.5 MHz of the second band pass filter 70.

On the other hand, as a result of detecting the broadcast signal from the tuner, when the broadcast method of the broadcast signal is the SECAM method, the driving signal is not generated from the detector 20 and the first switch 80 and the second switch 90 are turned off. Since no switching signal is generated, the holder 30 is not operated, and the first switching unit 80 and the second switching unit 90 remain in an on state to perform normal operation.

As described above, when the broadcast signal provided from the tuner is a PAL method, the holder 30 is operated by the operation signal from the detector 20 so that the broadcast signal provided from the ultra-short amplification unit 10 is a predetermined frequency (eg, For example, it is held at 32.4 MHz, and then filtered by the filtering unit 40 and demodulated by the IF demodulator 60 to an intermediate frequency to output an image signal and an audio signal. As a result, the first switching unit 80 and the second switching unit 90 are turned off.

As described above, in the noise removing apparatus of the HI-FI video cassette recorder according to the present invention, since band pass filtering according to a broadcasting method is performed, noise generated between sound signals is removed to improve sound quality. There is an effect that can output the sound signal.

Claims (1)

A device for filtering a broadcast signal provided from a tuner through a filter means, demodulating to an intermediate frequency through an IF demodulation means, and then outputting a video signal and an audio signal. Amplifying means for amplifying the broadcast signal provided from the tuner to a predetermined level; Discriminating means for discriminating a broadcast method of the broadcast signal provided from the tuner and generating an operation signal and a switching signal according to the determined broadcast method; Holding means for holding the broadcast signal amplified by the amplifying means by a drive signal from the discriminating means at a predetermined frequency; And And a band pass filter means for selectively performing band pass filtering according to the respective broadcasting schemes based on the switching signal from the discriminating means.