KR19980060786U - Signal trap circuit of VSI system - Google Patents

Abstract

The present invention relates to a signal trap circuit of a VSI system. In the related art, when a program reproduces a video signal from a recorded video tape and sends the video signal to an TV receiver through an RF modulator, a specific frequency range of 80 to 90 MHz is trapped. Although the circuit processing is performed with the circuit, the channel signal sent to the TV side is set to one of three channels or four channels, which is not compatible with user selection. When recording a video signal, the audio signal interferes with the video signal. It was difficult to avoid the cause of degrading the recording quality.

The present invention is connected to the rear end of the video signal output of the tuner and the IF unit 38 of the VSI system to improve the problems of the prior art as described above, and the audio trap unit 12 for trapping the audio signal, RF The present invention provides a signal trap circuit of a VSI system having a variable trap unit 13 connected to an input side of a modulator to remove signals affecting three or four channel frequencies.

Description

Signal trap circuit of VSI system

The present invention relates to a signal trap circuit of a VSI system, which makes it possible to provide a good quality of a video signal, especially during recording and reproduction of a video signal.

The VSI system is a device that receives various external video / audio sources to record and reproduce on a tape. The circuit block diagram of the VSI system is illustrated in FIG. 1.

Here, the microcomputer 31 for controlling the VSI system, the servo circuit 32 for driving control of a motor on the system deck side, the remote control unit 33a and the set side connected wirelessly to the remote control transmitter 33c. A timer circuit 33 to which the key portion 33b is connected, and an audio circuit 35 for processing a reproduction or audio recording signal in the system are provided.

The system also includes a video signal processing unit 37 for providing a recording signal to the tape side or processing a reproduced video signal from the RF signal provided from the tuner and the eye unit 38, and at the time of double speed reproduction on the system deck side. The DMSS unit 36 controls the audio signal to be provided in a normal state, and decodes data such as characters and graphics, such as KB PS, to select characters, graphics, and functions of various information on the screen. OSD unit 34 for displaying a character display of a menu screen, etc., a tuner and IF unit 38 for synchronizing a signal received from an antenna and generating an intermediate frequency signal, and VSI for providing system power. A power supply circuit 39 and the like.

On the other hand, in the system circuit as described above, a signal amplifier 41 is provided between the tuner, the eye section 38 and the video signal processing section 37, as shown in FIG. Between the 42 is provided a signal trap circuit 43 for filtering out a specific frequency of the video signal.

However, in such a conventional circuit, the audio signal interferes with the video signal output from the tuner and the IFF unit 38, and the quality of the recorded signal recorded on the tape of the deck unit 40 is deteriorated. Since the modulated video signal provided to the RF modulator 42 at the output of the OS 34 applies a trap circuit only to a specific channel frequency (for example, three or four channels), the compatibility of channel use in such a system is improved. It was difficult to guarantee.

The purpose of the present invention is to improve the above problems, the RF signal provided to the RF modulator while the external audio signal does not affect the video signal output from the tuner and the IF part of the VSI system is variable trap action By doing so, it is possible to obtain a good quality signal in such a system.

The present invention is connected to the rear end of the video signal output of the tuner and the IF part of the VSI system to implement the object of the above example, an audio trap part for trapping the audio signal, and connected to the RF modulator input side of the three or four channels It is characterized by a signal trap circuit of a VSI system having a variable trap section for removing signals affecting frequency.

Hereinafter, more specific features of the present invention will be understood by describing the same in detail with the accompanying drawings.

1 is a system circuit block diagram of a typical VCR (Video Cassette Recorder)

2 is a system circuit block diagram provided with a conventional signal trap circuit

3 is a system circuit block diagram provided with a signal trap circuit of the present invention

4A and 4B are exemplary embodiments illustrating the trap circuit in FIG. 3 in more detail.

** Explanation of symbols on main parts of the drawing **

1. Signal trap circuit

11. Microcomputer 12. Audio trap section

13. Variable trap

That is, Figure 3 shows an excerpt of a circuit block diagram of a system equipped with a signal trap circuit (1) of the VSI system according to the present invention.

Here, an audio trap unit 12 for trapping an audio signal is connected to the tuner and eye unit 38 of the VSI system at the rear end of the video signal output. A variable trap unit 12 is provided for removing signals affecting the channel frequency. On the other hand, the variable trap unit has three-channel traps and four appropriately selected when three or four channels are selected by user selection. Microcomputer 11 etc. to connect channel trap circuit are included.

In addition, the audio trap unit 12 includes a filter resistor R0 and a filter coil LO for trapping an audio signal among the video signal VS1 intermediate-processed by the tuner and IFF unit 38 as shown in FIG. 4A. And a filter circuit formed by a filter capacitor (CO). The variable trap unit 13 is a filter resistor and a coil for a three-channel or four-channel frequency signal among the RF signals VS2 output from the OS 34. And capacitor (R1, R2, L1, L2, C1, C2) circuits.

The present invention of such a configuration is a broadcast signal received from the antenna as shown in Figure 3 by the tuner of the microcomputer 11 and the tuner and the IF unit 38 is performed by the frequency synthesis method after the intermediate frequency processing The audio signal and the video signal are sent to the video signal processor 37 and the audio signal processor, respectively.

At this time, when the video signal is provided to the signal amplifying part 41 during the output of the tuner and the IF part 38, only the video signal from which the audio signal is removed from the audio trap part 12 in the front part is sent to the rear part. .

Therefore, when the microcomputer 11 records the video signal through the deck unit 40, the pure video signal without the influence of the audio signal can be recorded on the video signal, thereby improving the quality of the recorded signal recorded on the tape. will be.

In addition, when the playback operation is performed through the deck unit 40, the video signal detected by the video head of the deck unit 40 is demodulated through the video signal processing unit 37, which is again passed through the OS unit 34. It is provided to the RF modulator 42.

In this case, the RF modulator 42 is provided with a variable trap 13 as shown in FIGS. 3 and 5 at the front end. When the microcomputer 11 sends a control signal CS, the 3 and 4 channel traps are selectively selected. By connecting them, the trap function can be performed when the user selectively uses three or four channels.

The present invention is to ensure good circuit operation reliability of such a circuit by obtaining a good recording and reproduction system output of the video signal in the broadcast receiver system and playback and recording system circuit of the VSI system.

Claims (1)

In a VSI system including a tuner and an IF section 38, an ODS section 34, an RF modulation section 42, a microcomputer, and the like, a video signal of the tuner and IF section 38 of the VSI system An audio trap unit 12 connected to the output terminal for trapping an audio signal, a variable trap unit 13 connected to an RF modulator input side for removing signals affecting a 3 channel or 4 channel frequency, and A signal trap circuit of a VSI system characterized by including a microcomputer 11 or the like for selectively controlling the variable trap unit 13.