JP2515024B2 - Magnetic recording / reproducing device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a magnetic recording / reproducing apparatus for optimally controlling recording conditions.

[Conventional technology]

FIG. 5 is a block diagram of a signal system of a conventional magnetic recording / reproducing apparatus, in which 1 is a video signal input terminal and 2 is a video signal input terminal.
Is a pre-emphasis circuit, 3 is a white clip / dark clip circuit, 4 is an FM modulation circuit, and 5 is a recording amplifier. 6, 17 are switches for switching between recording and reproduction, 10 is a rotary transformer, 40 is a rotary drum, 41 and 42 are video heads, 50
Is a magnetic tape.

Also, 15 and 16 are playback preamplifiers, 14 is a channel switch circuit, 13 is an FM automatic gain control (FMAGC) circuit, and 12 is an FM.
A demodulation circuit, 11 is a demodulation output terminal.

 Next, the operation will be described.

First, in the recording mode, the video signal enters the input terminal 1 and is FM-modulated by the FM demodulation circuit 4 via the pre-emphasis circuit 2 and the white / dark clip circuit 3.
Then, the FM signal is amplified by the recording amplifier 5 and switched.
6,17 and the video heads 41,42 via the rotary transformer 10.
And is recorded on the magnetic tape 50.

Next, in the reproduction mode, the recorded signals are picked up by the video heads 41 and 42, and the rotary transformer 10 and
The reproduction preamplifiers 15 and 16 are input through the switch circuits 6 and 17 and amplified. The channel switching circuit 14 converts the amplified FM signal into a continuous FM signal for each channel. Next, after the gain is controlled by the FMAGC circuit 13, it is demodulated by the FM demodulation circuit 12, and the demodulated output is output from the output terminal 11.

In such a configuration, the gain of the recording amplifier 5 and the frequency deviation of the FM modulator 4 are individually adjusted in the production process. In other words, the variation of the video head, the rotary transformer, or the like, or the variation of the gain of the recording system circuit is corrected and optimally adjusted.

[Problems to be Solved by the Invention]

The conventional magnetic recording / reproducing apparatus is configured as described above, and includes the gain of the recording amplifier and the FM when recording, including variations in the recording / reproducing sensitivity of the recording system circuit such as the video head.
It was necessary to adjust the frequency deviation of the modulator to some fixed value. For example, when considering the variation of the heads, the recording level should be adjusted according to the individual heads, but to do so, it is necessary to confirm recording and reproduction individually, and it is necessary to carry out in the production process. There are problems such as taking too much time, and the reality is that it has not been implemented.

The present invention has been made to solve the above problems, and an object thereof is to obtain a magnetic recording / reproducing apparatus capable of automatically setting the optimum recording state of a video head.

Another object of the present invention is to obtain a magnetic recording / reproducing apparatus capable of automatically setting the frequency deviation of the FM modulator to a predetermined level.

[Means for solving the problem]

The magnetic recording / reproducing apparatus according to the present invention sets the tape in the rewinding state for a certain period of time at the time of recording suspension, and sets the tape in the reproduction state in the rewinding period or the phase matching period after the suspension is released. The level of the recording signal reproduced in the reproducing state is detected, and a comparison calculation is performed with the initial setting value, and the gain of the recording amplifier is controlled by the comparison calculation output at the time of switching to the recording mode. It is a thing.

Further, the magnetic recording / reproducing apparatus according to the present invention keeps the tape in the rewinding state for a certain period of time at the time of recording suspension,
The tape is put into a reproducing state during the rewinding period or the phase matching period after the suspension is released, and the level of the recording signal reproduced during the reproducing state is detected and compared with the initial setting value. The frequency deviation of the FM modulator is controlled by the output of the comparison operation at the time of switching to the recording mode.

[Action]

In the magnetic recording / reproducing apparatus according to the present invention, since it is configured as described above, the recording level corresponding to the magnetic tape or the magnetic head can be obtained without the need for a new apparatus for generating the adjustment signal. Adjustments are made.

In the magnetic recording / reproducing apparatus according to the present invention,
With the above-mentioned configuration, the frequency deviation can be adjusted according to the magnetic tape and the magnetic head without requiring a new device for generating the adjustment signal.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a magnetic recording / reproducing apparatus according to an embodiment of the present invention, in which 18 is a detection circuit for peak detection of a reproduced FM signal, 19 is an A / D converter for A / D converting the detection output, 20
Receives the output signal from the A / D converter and the control signals 21 and 22 for determining the timing of recording pause and recording start, calculates the difference between the reproduction level and the initial setting value, and A microprocessor that generates an output that controls the gain (abbreviated as CPU below). Further, the CPU 20 generates a control output 23 for switching the switches 6 and 17 to the reproducing side for an appropriate time at the timing of recording pause and recording start. The other structure is the same as that of the conventional example shown in FIG. 5, and the description thereof is omitted.

FIG. 3 is a diagram showing a state in which the tape is running for operation. In the figure, 101 is an audio track, 201 is a video track, 301 is a control track, and 401 is a tape.

 Next, the operation will be described.

FIG. 4 is a diagram showing a relationship between tape running and time when recording is temporarily stopped.

Usually, in order to eliminate the disturbance of the image at the time of splicing and recording, the tape is rewound for a certain period of time to be in a pause state, and at the start of recording, a certain time phase matching reproduction state is set and then recording is started. To further explain with reference to FIG. 3, the recording pause (RE
C PAUSE), it rewinds by 33 control pulses recorded on the control track every frame at the time of recording, and becomes a pause state. Then, in the recording start mode, the phase matching reproduction state is set for 30 frames (about 1 second), and the recording state is switched by synchronizing with the previously recorded control signal.

FIG. 4 shows this timing relationship. First, the signal RS is a control signal for rewinding the tape for 33 control pulses at the time of recording pause (REC PAUSE). The control signal REC2 is a signal that switches at the time of REC PAUSE, and the control signal SV-REC is a signal that switches at the time of ending phase matching reproduction after the start of REC. The switching control pulse 23 is generated by the above two control signals 21 and 22. When the switching pulse 23 is generated from the control signals 21 and 22 input to the CPU 20,
At the same time when the switches 6 and 17 are switched to the reproduction side, the reproduction processing circuit is also in the reproduction state, the reproduction FM signal is detected during the phase matching reproduction period, and this level is input to the CPU 20 via the A / D converter. Next, the CPU 20 compares the initial setting level with the level from the A / D converter, calculates the difference, and corrects the setting level that determines the gain of the recording amplifier 5 based on the difference output.

In the above embodiment, an example of detecting the average of both channels (L and R channels) and correcting the recording current is shown. However, in order to correct the variation between individual heads, the output is detected for each channel. Alternatively, the recording level may be corrected for each.

Next, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 2 shows a magnetic recording / reproducing apparatus according to a second embodiment of the present invention. In the figure, the same components as those in the first embodiment shown in FIG. . twenty four
Is an A / D converter for A / D converting the FM demodulation output, 25 is an A / D converter 2
The output from 4 and the input of control signals 21 and 22 for determining the timing of recording pause and recording start are compared with the initial setting value of the reproduction level and the output of the A / D converter 24, and the difference is calculated. It is a CPU that calculates and generates an output that controls the frequency deviation of the FM modulator 4.

 Next, the operation will be described.

Similar to the first embodiment, when the switching pulse 23 is generated from the control signals 21 and 22 input to the CPU 25, the switches 6 and 17 are switched.
Is switched to the reproducing side, the reproducing processing circuit is also in the reproducing state at the same time, and the reproduced FM signal is detected during the phase matching reproducing period, and this is input to the CPU 25 via the A / D converter 24. CPU25
Compares the default setting level with the A / D converted level,
The difference is calculated, and the set level for determining the frequency deviation of the FM modulator 4 is corrected by the output of the difference.

In the second embodiment, the FM demodulation output is detected and the FM
Although the frequency deviation of the modulator is corrected, the output of the reproduction processing circuit after the FM demodulator may be detected to correct the input level input to the FM modulator.

〔The invention's effect〕

As described above, according to the magnetic recording / reproducing apparatus of the present invention, the tape is not rewound for a certain period of time when the recording is temporarily stopped, and the tape is rewound during the rewinding period or the phase matching period after the suspension is released. Is set as the reproduction state, and the level of the recording signal reproduced in the reproduction state is detected and the calculation is compared with the initial setting value. At the time of switching to the recording mode, the gain of the recording amplifier is obtained by the comparison calculation output. The magnetic recording / reproducing apparatus capable of individually adjusting the recording level adapted to the characteristics of the head and the tape can be obtained without adding a device for generating a signal for adjustment. Therefore, there is an effect that the recording level can be adjusted according to the magnetic tape and the magnetic head without increasing the circuit scale and the area of the device.

Further, according to the magnetic recording / reproducing apparatus of the present invention, the tape is rewound for a certain period of time at the time of recording suspension, and the tape is reproduced in the rewinding period or the phase matching period after the suspension is released. The level deviation of the recording signal reproduced during the reproduction state is detected, the value is compared with the initial setting value, and the frequency deviation of the FM modulator is output by the comparison calculation output at the time of switching to the recording mode. A magnetic recording / reproducing apparatus capable of individually adjusting the frequency deviation adapted to the characteristics of the head and the tape, and a device for generating a signal for adjustment. It can be obtained without adding, and thereby, without increasing the circuit scale and the area of the device,
There is an effect that the frequency deviation can be adjusted according to the magnetic tape and the magnetic head.

[Brief description of drawings]

FIG. 1 is a diagram showing a magnetic recording / reproducing apparatus according to a first embodiment of the present invention, FIG. 2 is a diagram showing a magnetic recording / reproducing apparatus according to the second embodiment of the present invention, and FIG. FIG. 4 is a diagram showing tape running for the purpose, FIG. 4 is a diagram showing timing at the time of recording suspension, and FIG. 5 is a diagram showing a conventional magnetic recording / reproducing apparatus. 1 is an input terminal, 2 is a pre-emphasis circuit, 3 is a white clip / dark clip circuit, 4 is an FM modulation circuit, 5
Is a recording amplifier, 6, 17 are switches, 10 is a rotary transformer, 40
Is a rotary drum, 41 and 42 are video heads, 50 is a magnetic tape, 15 and 16 are reproduction preamplifiers, 14 is a channel switch circuit, 13 is an FM gain control (AGC) circuit, 12 is an FM demodulation circuit, and 1
1 is a demodulation output terminal, 18 is a detection circuit, 19 and 24 are A / D converters, 2
Reference numerals 0 and 25 are microprocessors (CPUs), 101 is an audio track, 201 is a video track, 301 is a control track, and 401 is a tape. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (2)

(57) [Claims] 1. When the recording is paused, the tape is not rewound for a certain period of time, and the tape is not replayed during the rewinding period or the phase adjustment period after the suspension is released. It is characterized in that the level of the recording signal to be reproduced is detected, a comparison is made with the initial setting value, and the gain of the recording amplifier is controlled by the comparison calculation output at the time of switching to the recording mode. Magnetic recording / reproducing device. 2. When the recording is paused, the tape is not rewound for a certain period of time, and the tape is not replayed during the rewinding period or the phase adjustment period after the suspension is released. The level of the recorded signal to be reproduced is detected and compared with the initial setting value. When the recording mode is switched, the FM
A magnetic recording / reproducing apparatus, which is configured to control a frequency shift of a modulator.