KR950000356Y1 - Audio dubing circuit - Google Patents

Abstract

No content.

Description

Audio Dubbing

1 is a circuit diagram of a conventional audio dubbing apparatus.

2 is a waveform diagram of oscillation and head input signals during audio dubbing.

3 is a configuration diagram of a signal recording state of a video tape.

4 is a circuit diagram of an audio dubbing apparatus of the present invention.

* Explanation of symbols for the main parts of the drawings

7: recording / playing head 8: audio muting head

9: Full width erase head 10: Oscillation means

11: signal supply control means 12: Oagate

13: record amplifier

The present invention relates to an audio dubbing device such as a VCR, a camcorder, and an audio device having an audio dubbing function. In particular, the bias signal and the erase signal during dubbing are properly switched by one oscillation means and the output of the oscillation means for each head. The present invention relates to an audio dubbing device having a means for providing an audio dubbing circuit with a simple circuit configuration.

Referring to FIG. 1, the audio dubbing apparatus applied to the conventional VCR records / reproduces the erase signal to the first oscillator 2 for supplying the erase signal to the full-width erasing head 1, and the audio erase head 3 to the erase unit. A second oscillation unit 5 for supplying a write bias signal to the head 4 and a recording amplifier 6 for amplifying and supplying a record signal REC-H to the recording / reproducing head 4, R1 to R8 are resistors, C1 to C8 are resistors, C1 to C8 are capacitors, Q1 to Q5 are transistors, L1 is a coil, T1 and T2 are transformers, VCC is a power supply, and VR1 is a variable resistor for adjusting the write bias signal level.

The operation of the conventional audio dubbing device configured as described above is as follows.

First, in the recording mode, the recording control signal REC-H is a high signal, and the dubbing control signal DUB-L is supplied with a low signal to the bases of the transistors Q3 and Q5 of the respective oscillators 2 and 5. .

Therefore, since the transistor Q3 is turned on and the transistor Q2 is turned off, the oscillator composed of the transistor Q1, the resistors R1, R2, R3, and the capacitors C1, C2, C3, and the transformer T1 is turned on. The oscillation operation causes a 70KHz sine wave signal to be outputted to the secondary side P4 of the transformer T1 as shown in FIG. The entire track, i.e., the audio track (a), the video / hi-track (b), and the control track (c) are all erased.

On the other hand, as the transistor Q5 is turned off, an oscillator comprising a transistor Q4, resistors R5, R6, R7, and capacitors C4, C5, C6, C7, and a transformer T2 oscillates. Thus, a sinusoidal wave signal of 70 KHz is outputted to the transformer T2 secondary side P2 and P4 as shown in FIGS. 2B and 2D, respectively, and the signal of FIG. The audio track (a) is erased, and the signal of (b) is controlled by the variable resistor VR1, and the level of the recording signal (audio signal) amplified by the recording amplifier 6 (REC-H; (a) is applied to the recording / reproducing head 4 by biasing as shown in (c) of FIG. 2 (P3; see (c) of FIG. 2) to record a new signal on the audio track (a). .

In other cases, in the dubbing mode, the recording control signal REC-H is input to the oscillator 2 and 5 as a low signal and the dubbing control signal DUB-L is a low signal.

Therefore, since the transistor Q3 is turned off and the transistor Q2 is turned on, the transistor Q1 is turned off so that the oscillator does not oscillate, and the transistor Q5 is turned off so that the second oscillator 5 is the same. The oscillation operation is performed to record the amplifier lock signal P3 biased to the audio track a.

That is, during recording, both the first and second oscillators 2 and 5 are operated so that the entire video tape track is erased, and new audio, video and control signals are recorded thereon, and during dubbing, the second oscillator 5 ) To record the new audio signal by removing the audio track while leaving the existing video and control signals intact.

However, according to the conventional audio dubbing apparatus as described above, since an oscillator operating in correspondence with each of the signal recording and dubbing modes is configured separately, the circuit configuration is complicated, and noise and operation disorder due to two mutual interferences are generated.

The present invention provides an oscillation signal to each head from one oscillation means that supplies an oscillation signal in both recording and dubbing mode, thereby simplifying the circuit configuration and preventing the occurrence of noise and motion disturbance due to oscillation signal interference. An object of the present invention is described below with reference to the accompanying drawings, the configuration of the present invention as follows.

Referring to FIG. 4, the audio dubbing apparatus of the present invention provides a recording bias signal for the recording / reproducing head 7, an audio erasing signal for the audio erasing head 8, and a full width erasing signal for the full width erasing head 9. Signal supply control means 11 for supplying or blocking control of the oscillating means 10 for supplying and the head 7, 8, 9 to the output signal of the oscillating means 10 in response to the recording mode or the derby mode. And an oragate for supplying a recording control signal REC-H and a dubbing control signal DUB-H such that the oscillation means 10 and the signal supply control means 11 operate in response to a recording mode or a dubbing mode. And a recording amplifier 13 which amplifies the recording signal REC-IN and supplies it to the recording / reproducing head 7.

In the drawings, R9 to R17 are resistors, C10 to C14 are capacitors, VC1 is a variable resistor for adjusting the write bias signal level, T3 is a transformer, Q6 to Q10 are transistors, L1 is a coil, VCC is a power supply, D1 and D2 are diodes.

The operation of the audio dubbing apparatus of the present invention configured as described above is as follows.

First, in the recording mode, the recording control signal REC-H is input as a high signal and the dubbing control signal DUB-H is input as a low signal.

When the dubbing control signal DUB-H becomes a low signal, the signal supply control means 11 switches the switching so that the erase signal can be supplied to the audio erase head 8 and the full width erase head 9 (transistors Q9 and Q10). Off), and the recording control signal REC-H is input as a high signal, the oscillation means 10 starts oscillation.

That is, since the high signal is applied to the base of the transistor Q8 through the diode D2 of the oragate 12 and the transistor Q8 is turned on, the transistor Q7 is turned off so that the transistor Q6 and the resistor R9 ( An oscillator consisting of R10, R11, condensers C10, C11, C12, C12, and transformer T3 is oscillated.

Therefore, the oscillation signals such as (b) and (d) of FIG. 2 are respectively output from the secondary side P4 of the transformer T3, and the oscillation signals such as (d) and (4) of FIG. Since transistors Q9 and Q10 are turned off at 11, they are supplied to the audio erasing head 8 and the full erase head 9 through resistors R13 and R14, respectively, to perform audio track erasing and full erasing operations.

An oscillation signal such as (b) (2) of FIG. 2 is biased to the recording signal (audio signal) REC-IN (P1) amplified by the recording amplifier 13 as shown in (c) (P3) of FIG. Is supplied to the recording / playback head 7 so that signal recording is performed.

In the dubbing mode, the recording control signal REC-H is input low and the dubbing control signal DUB-H is input high.

When the dubbing control signal DUB-H is input as a high signal, a high signal is applied to the base of the transistor Q8 through the diode D1 of the oragate 12 so that the transistor Q8 is turned on, thus oscillating as described above. The means 10 is operated, and the signal supply control means 11 supplies the erase signal, which is the output of the oscillation means 10, to the audio erase head 8 only by the dubbing control signal DUB-H. The erase head 9 is switched so as not to be supplied.

That is, since the dubbing control signal DUB-H biases the bases of the transistors Q9 and Q10 with a high signal, the full-width erase signal (oscillating means) supplied to the full-width erasing head 9 through the resistor R14. The output P4 of (10) is made zero ("0") potential, so that the output P4 of the oscillation means 10 is not supplied to the full-width erasing head 9, and the resistor R13 The erase signal is supplied only to the audio erase head 8 to erase the audio track.

At this time, transistor Q9 is turned on in the (+) period of the erase signal as shown in (d) (P4) of FIG. 2 to block the erase signal of the (+) cycle, and transistor Q10 is turned on in the (-) cycle. By eliminating the erase signal in the negative period, the potential of the erase signal input to the full-width erasing head 9 is made zero.

As described above, as the oscillating means 10 operates, the output of the audio track is biased to the amplifier lock signal output P1 and applied to the recording / reproducing head 7 by the output P2. The signal is recorded.

As described above, according to the present invention, since only one oscillation means is provided to erase, record, and dub audio and video signals, cost reduction and power consumption can be reduced by simplifying circuit configuration. This eliminates the malfunction caused by mutual interference and noise, and it is effective in improving the reliability of circuit operation and the quality of equipment.

Claims (3)

An oscillating means (10) for supplying a recording bias signal to the audio recording / reproducing head (7), an audio erasing signal to the audio erasing head (8), and a full width erasing signal to the full width erasing head (9); Signal supply control means 11 for supplying or blocking the output signal of 10 to the heads 7, 8, 9 in response to the recording mode or the dubbing mode, and the oscillation in response to the recording mode or the dubbing mode. The oragate 12 which supplies the recording control signal REC-H and the dubbing control signal DUB-H so that the means 10 and the signal supply control means 11 operate, and the recording signal REC-IN. An audio dubbing device comprising a recording amplifier (13) for amplifying and supplying the recording / reproducing head (7). 2. The signal supply control means (11) according to claim 1, wherein the signal supply control means (11) comprises: a resistor (R13) for supplying an audio mute signal and a resistor (R14) for supplying a full-width mute signal, and the full-width erase head (15) when a dubbing control signal is input. 9) An audio dubbing apparatus comprising a transistor Q9 for positive period switching of a signal supplied to 9), a transistor Q10 for negative period switching, and a bias resistor R15 and R16 thereof. 2. An audio dubbing apparatus according to claim 1, wherein the signal supply control means (11) is composed of switching transistors (Q9) (Q10) which prevent the operation of the full width erase head (9) upon inputting a dubbing control signal.