KR890004697Y1 - Recording and reproducing circuit of audio signals - Google Patents

Abstract

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Description

Sound signal recording / playback device for video tape recorder

1 is a schematic configuration diagram of an apparatus of the present invention.

2 is a detailed circuit diagram of FIG.

3A is a schematic configuration diagram of a recording signal generator for a conventional video tape recorder. FIG. 3 (b) shows a state in which a video signal and an audio signal are recorded on a video tape.

* Explanation of symbols for main parts of the drawings

1: Image signal processing input 2: Image signal discrimination circuit

3: vertical synchronous signal separation circuit 4: recording command signal input

5: AND gate 6, 8, 10: buffer

7: 60HZ vertical synchronous signal generator 9: inverter

The present invention relates to a device for recording and reproducing an audio signal using a synchronous signal as a reference signal in a video tape recorder. In particular, a vertical synchronizing signal is generated even when only an audio signal is input without a video signal. The present invention relates to a sound signal recording and reproducing apparatus that enables a video tape recorder to perform a function such as a sound tape recorder by enabling recording and playback.

In general, a video tape 31, a control fence signal 32 as a reference signal, and a sound signal 33 are recorded in a predetermined pattern on a video tape as shown in FIG. 3 (b).

Here, the acoustic signal 330 is recorded on the top of the tape 34, the Youngsan signal 31 is recorded inclined at the center of the tape 34, and the control pulse signal 32 is recorded at the bottom of the tape 34.

The control pulse signal 32 is used by dividing the vertical synchronization signal of the video signal 31 in half.

Referring to FIG. 3 (a), as a conventional recording / playback value, the video signal is input to the recording and reproducing circuit 35, and the video signal is transferred to the magnetic tape 34 by the video recording and reproducing head 36. b) Record and playback in the pattern shown in the figure.

The vertical synchronizing signal in the recording and reproducing circuit 35 is applied to the servo circuit 37 to generate a control pulse signal which becomes a reference for recording and reproducing the video signal on the magnetic tape 34 to control the head 38. Is recorded at the lower end of the magnetic tape 34 and the sound signal is inputted to the sound recording and reproducing circuit 39 and recorded at the upper end of the magnetic tape 34 through the sound head 40.

In such a conventional recording and reproducing apparatus, in order for the image head 36 to accurately scan a predetermined pattern of tracks such as the third (b) on the tape, precise tape speed and speed control of the image head 36 are required. To record only sound signals (i.e., to record FM or AM broadcasts of radios without watching TV broadcasts), even though there are sound signal recording and playback signals 39 inside the VTR, The control pulse signal cannot be generated because there is no Youngsan signal, and thus there is a disadvantage in that the sound signal cannot be recorded and reproduced in the VTR alone.

The present invention provides a 60MH vertical synchronous signal generator to solve the above-mentioned drawbacks so that sound signals can be recorded on a videotape recorder even when there is no video input. An object of the present invention is to provide a sound signal recording and reproducing apparatus for a VTR, which eliminates the need to purchase a tape recorder. Hereinafter, the construction and effect of the present invention will be described with reference to the accompanying drawings.

Referring to FIGS. 1 and 2, the device of the present invention comprises a video signal processing input 1 connected to a video signal discrimination circuit 2 and a vertical synchronous signal separating circuit 3, and a recording command signal input ( 4) and the output of the video signal discrimination circuit 2 to the input of the AND gate 5 and the output of the AND gate 5 to the B ⁺ power buffer 6 and the buffer of the 60MH vertical synchronous signal generator 7 8), but connected to the control terminal of the buffer (10) connected to the vertical synchronous signal separation circuit (3) through the inverter (9), and the output of the buffer (8, 10) to the servo circuit (11) However, the configuration is made by connecting the 60MH vertical synchronous signal generator 7 between the B ⁺ power buffer 6 and the buffer 8, the operation of such a configuration is as follows.

First, if there is a video signal, the video processing signal is applied to the video signal processing input 1, so that the output of the video signal discrimination circuit 2 is 'low' and the logic is 'high' to the recording command signal input 4. Since the write command signal is applied, the output of the AND gate 5 becomes 'low' so that the buffers 6 and 8 are turned off and B ⁺ power is not supplied to the 60MH vertical synchronous signal generator 7 so that the servo circuit 11 Although the output from the 60MH vertical synchronous signal generator 7 is not applied, the 'high' signal is applied to the buffer 10 by the inverter 9 so that the buffer 10 is in a conductive state. The vertical synchronous separation signal from the vertical synchronous signal separation circuit 3 is applied to record the video signal and the audio signal as in the normal recording in the VTR.

In addition, when the video signal does not exist, the output of the video signal discrimination circuit 2 becomes 'high' and the write command signal, which is also logic 'high', is applied to the write command signal input 4, so that the AND gate 5 The output is logic 'high' so that the B ⁺ power buffer 6 is in the conduction state and is supplied to the B ⁺ power supply to the 60MH vertical synchronous signal generator 7 so as to generate a 60MH vertical synchronous signal. Since the 'high' signal is applied, the buffer 8 is in a conductive state, and the 60MH vertical synchronizing signal is supplied to the servo circuit 11.

At this time, the output of the logic 'high' of the AND gate 7 is inverted to a logic 'low' in the inverter 9 and applied to the buffer 10, so that the buffer 10 is blocked.

Therefore, since the 60MH vertical synchronization signal is supplied to the servo circuit 11, only the sound signal is recorded.

Since there is no video signal, no video signal is recorded on the magnetic tape.

2 shows a detailed circuit of the FIG. 1 configuration.

Here, the B ⁺ power buffer 6 is composed of a switching transistor TR ₂ and a control transistor TR ₁ , and the buffer 8 includes transistors TR ₅ , TR ₆ , a diode D ₁ , and a coupling capacitor. (C ₃ ), the buffer 10 is composed of transistors TR ₈ , TR ₉ , a diode D ₂ , and a coupling capacitor C ₄ , and the 60MH vertical synchronous signal generator 7 is a multivibrator. It can be seen that it is composed of transistors TR ₃ and TR ₄ , resistors R ₁ to R ₄ , and capacitors C ₁ and C ₂ .

Since the operation of the configuration of FIG. 2 is normal, detailed description thereof will be omitted.

As described above, according to the present invention, by supplying a 60MH vertical synchronous signal to the servo circuit 11 which makes a video signal control pulse signal, recording and reproducing of the audio signal can be performed by the VTR alone. You can add functionality.

Claims (1)

The video signal processing input 1 is connected to the video signal discriminating circuit 2 and the vertical synchronous signal separating circuit 3, and the output of the recording command signal input 4 and the video signal discriminating circuit 2 is AND gate 5 ) And the output of AND gate (5) is commonly connected to B ⁺ power buffer (6) and buffer (8) of 60MH vertical synchronous signal generator (7), and through synchronous signal (9) Connect to the control terminal of the buffer 10 connected to the separation circuit 3, and connect the outputs of the buffers 8 and 10 to the servo circuit 11, but between the B ⁺ power buffer 6 and the buffer 8 60MZ A sound signal recording / reproducing apparatus for a video tape recorder connected by connecting a vertical synchronous signal generator (7).