JPH06162503A - High frequency correcting circuit for double speed dubbing - Google Patents

Abstract

PURPOSE:To upward or downward correct the high frequency levels of a repro duced signal which is dubbed at a high speed and to make the width of the correction variable. CONSTITUTION:A switch 22 switches the head 32 of a recording/reproducing mechanism 20 to a recording side and the reproduced signals from a reproducing mechanism 2 are recorded on a tape 46 of the mechanism 20. On the other hand, the high frequency components included in the reproduced signals obtained by a filter 34 are given to a control circuit 12, then, the switch 22 is switched to the reproducing side and the reproduced signals which are reproduced by the head 32 of the mechanism 20 are inputted to the filter 34. The high frequency components included in the reproduced signals obtained in the filter 34 are given to the circuit 12, the circuit 12 outputs the adjustment signals corresponding to the comparison of the respective high frequency components of the both reproduced signals to a bias oscillating circuit 30 and the circuit 30 gives different level outputs to the head 32 corresponding to the adjustment signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency correction circuit for double speed dubbing.

[0002]

2. Description of the Related Art For example, in a double cassette tape recorder, double speed dubbing is performed by setting one of the respective cassette tapes in a double speed playback state and the other in a double speed recording state, so that the playback speed of the cassette tape increases. It is known that the high frequency components of the signal are usually lowered in level due to the saturation characteristic of the head and the like, and as a result, the audibility when reproducing the double-speed dubbed magnetic tape is deteriorated. Further, the high frequency component may increase in level depending on the characteristics of the cassette tape.

Therefore, there has been a high-frequency correction circuit for double-speed dubbing in order to correct the high-frequency level in double-speed dubbing to the up side or the down side. This conventional high-frequency correction circuit is a combination of a resistor and a capacitor, and the high-frequency correction is fixed.

[0004]

As described above, in the conventional high-frequency correction circuit, since the high-frequency correction is fixed, the reproduced signal dubbed at double speed is increased beyond the fixed correction. It is not possible to make it down or down, but this is not enough to deal with the fact that the correction width of the high frequency level differs depending on the type of magnetic tape loaded in the tape recorder, and once the high frequency correction circuit After incorporating in the tape recorder,
Even if it is necessary to add high-frequency correction again, this cannot be dealt with, and double-speed dubbing occurs when the high-frequency correction does not work.

Therefore, in the present invention, a high-frequency correction circuit excellent in high-frequency correction that can increase or decrease the high-frequency level of a reproduction signal dubbed at double speed and can also change the correction width of the level is provided. It is intended to be provided.

[0006]

In order to achieve such an object, in the high speed correction circuit for double speed dubbing of the present invention, the head of the recording / playback mechanism is adjusted to the recording side in the double speed dubbing mode. In the mode, it is switched to the reproducing side. When it is the recording side, the reproducing signal from the reproducing device is outputted to the head, while when it is the reproducing side, the head switching means for outputting the reproducing signal reproduced by the head, and adjustment Bias oscillating means for selectively switching outputs of different levels to the head in response to a signal, a reproducing signal from a reproducing mechanism, and a reproducing signal applied to the reproducing side through the head switching means in the switching state. Of the frequency components included in the reproduction signal switched by the reproduction signal switching means and input by the reproduction signal switching means. A filter means for obtaining a required high frequency component, and a control means for comparing the high frequency components of the reproduction signals supplied from the filter means and outputting an adjustment signal corresponding to the comparison to the bias oscillation means. It is characterized by having.

[0007]

The head of the recording / reproducing mechanism is switched to the recording side in the double speed dubbing mode by the head switching means, and the reproduction signal from the reproducing mechanism is recorded on the recording medium of the recording device by the double speed dubbing. On the other hand, the reproduction signal switching means is switched to the reproduction signal side from the reproduction mechanism to obtain the high frequency component contained in the reproduction signal by the filter means, and this is given to the control means.

Next, the head switching means is switched to the reproducing side to output a reproduction signal reproduced by the head of the recording / reproducing mechanism, and this is inputted to the filter means through the reproduction signal switching means. At the same time, a high frequency component included in the reproduction signal for double speed dubbing is obtained, and this high frequency component is given to the control means.

The control means compares the given high frequency components and outputs an adjustment signal corresponding to the comparison to the bias oscillating means. In the bias oscillating means, in response to the adjustment signal, outputs of different levels are selectively switched and given to the head.

As a result, when the level of the high frequency component of the reproduction signal double-speed dubbed in the recording / reproducing mechanism is down or up, the bias oscillation is generated in response to the adjustment signal from the corresponding control means. As a result of varying the output level of the means, the high frequency component of the reproduced signal is adjusted and double speed dubbing is performed on the recording medium in the recording / reproducing mechanism.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 includes a recording / reproducing mechanism, a reproducing mechanism, a high frequency correction circuit for double speed dubbing according to an embodiment of the present invention, and a peripheral circuit thereof. It is a circuit diagram inside a deck. Since the same applies to other channels, for example, the R channel, the details thereof will be omitted.

Referring to this figure, the reproducing mechanism 2 has a reproducing head 4, a cassette tape drive motor 6 and a head movable plunger 8, and reproduces and drives the cassette tape 10 by these, During reproduction, the cassette tape 10 is driven at a normal reproduction speed, and during double-speed dubbing, the cassette tape 10 is driven at a predetermined multiple of the normal reproduction speed. These drives are controlled by the tape recorder control circuit 12. The reproduction signal by the normal reproduction and the reproduction signal by the double speed dubbing from the reproduction mechanism 2 are given to the reproduction output changeover switch 16 and the dubbing switch 18 via the reproduction equalizer 14, respectively.

The reproduction output changeover switch 16 is the reproduction mechanism 2
Is reproduced by the reproduction equalizer 14 and one contact 16
The reproduction signal given to a, the head changeover switch 22 and the reproduction equalizer 24 which are reproduced by the recording / reproducing mechanism 20.
The reproduction signal applied to the other contact 16b via the switch is output to the outside by switching the movable contact 16c.

The dubbing switch 18 uses the reproduction signal reproduced by the reproduction mechanism 2 and given to one contact 18a via the reproduction equalizer 14 as a recording signal for double speed dubbing from the external recording / reproducing device via the other contact 18b. The supplied signal is used as a recording signal for normal recording and is applied to the recording equalizer 26 and the reproduction signal changeover switch 28 by switching the movable contact 18c.

The recording equalizer 26 is connected to the head changeover switch 22 and the bias oscillating circuit 30, and the recording signal given from the dubbing switch 18 is recorded / reproduced by the recording / reproduction mechanism 20 via the head changeover switch 22. Give to the head 32.

The reproduction signal changeover switch 28 is a reproduction signal applied to one contact from the reproduction mechanism 2 via the reproduction equalizer 14 and the dubbing switch 18, and the recording / reproduction applied via the head changeover switch 22 and the reproduction equalizer 24. The reproduction signal provided from the mechanism 20 to the other contact 28b is selectively switched by the movable contact 28c and output to the bandpass filter 34.

The band-pass filter 34 has a required high frequency component of, for example, 8 to 10 kHz among the frequency components included in the reproduction signals from the reproduction mechanism 2 and the recording / reproduction mechanism 20 supplied from the reproduction signal changeover switch 28. The frequency component is obtained.

The head changeover switch 22 contains a pair of switches 36 and 38, and one switch 36 has a recording side contact 36a connected to the recording equalizer 26, a grounded reproduction side contact 36b, and a recording / reproducing head. A movable contact 36c connected to one end of the switch 32, and the other switch 3
8 is a reproduction side contact 38 connected to the reproduction equalizer 24.
a, a recording side contact 38b grounded, and a movable contact 38c connected to the other end of the recording / reproducing head 32, both movable contacts 36c and 38c are interlocked,
In response to the drive signal from the tape recorder control circuit 12, the recording / reproducing head 32 of the recording / reproducing mechanism 20 is switched to the recording side contacts 36a and 38b in the double speed dubbing mode and to the reproducing side contacts 36b and 38a in the high frequency correction mode. The movable contacts 36c and 38c are driven so as to be connected.

The recording / reproducing mechanism 29 comprises the recording / reproducing head 32, an erasing head 40, a cassette tape drive motor 42, and a head movable plunger 44, and the recording / reproducing head 32 is the head as described above. The erase head 40 is connected to the changeover switch 22, one end of which is connected to the bias oscillating circuit 30 and the other end of which is grounded. The erase head 40 drives the cassette tape 46 for reproduction. At the recording / playback speed, the cassette tape 46 is driven at a predetermined multiple of the normal recording speed during double speed dubbing. These drives are controlled by the tape recorder control circuit 12.

The bias oscillating circuit 30 is configured to selectively output different levels of output to the recording / reproducing head 32 of the recording / reproducing mechanism 20 in response to the adjustment signal from the tape recorder control circuit 12. There is. The outline of this configuration will be described with reference to FIG. 2. The bias oscillation circuit 30 includes three switching transistors TR1 to TR3 to which the control signals from the tape recorder control circuit 12 are applied to their respective bases, and the switching transistors TR1 to TR3. Resistors Rb to the collectors of the transistors TR1 to TR3
Switching transistor TR connected via Rg
4, a Zener diode ZD, a bias oscillation block OB, a resistor Ra, and a capacitor C. The details of such a configuration will be described later in combination with the operation.

The tape recorder control circuit 12 has a built-in microcomputer, and as described above, controls the operation of the head changeover switch 22 and the selection of the oscillation output level of the bias oscillation circuit 30, and the reproducing mechanism 2 and the recording / reproducing mechanism 20. The respective motors 6, 42 and the plungers 8, 44 are controlled, and the bandpass filter 34
The reproduction signal given from the above is stored, the high frequency components of the stored reproduction signals are compared with each other, an adjustment signal corresponding to the comparison is generated, and the output is controlled to the bias oscillation circuit 30. ing. The key matrix circuit 48 includes keys for instructing and operating the operation of the tape recorder control circuit 12.

The operation will be described with reference to the flowchart of FIG.

When the key operation for the double speed dubbing of the key matrix circuit 48 is performed, the double speed dubbing is started.
The tape recorder control circuit 12 includes a key matrix circuit 4
In response to the double speed dubbing start command input from the motor 8, the motors 42 of the recording / playback mechanism 20 and the playback mechanism 2,
Recording / playback mechanism 2 by controlling 6 and plungers 44, 8
0 and the cassette tapes 46 and 10 mounted on the playback mechanism 2 are driven at double speed (steps 1 and 2).
As a result, the reproduction mechanism 2 reproduces the signal recorded on the cassette tape 10 at a double speed, thereby outputting the reproduction signal from the reproduction mechanism 2 while the recording / reproduction mechanism 20.
Then, the signal is recorded on the cassette tape 46 at a double speed.

Further, the movable contact 1 of the dubbing switch 18
8c to the contact 18a side of the dubbing recording side, the movable contact 28c of the reproduction signal changeover switch 28 to the input side contact 28a side of the reproduction signal from the reproduction mechanism 2, and the head changeover switch 22.
To the dubbing recording side contacts 36a, 38b, respectively (steps 3, 4, 5). The reproduction signal reproduced from the cassette tape 10 of the reproduction mechanism 2 is given to the recording equalizer 26 and the reproduction signal changeover switch 28 via the reproduction equalizer 14 and the dubbing switch 18. Then, the reproduction signal given to the recording equalizer 26 is transmitted via the head changeover switch 22 to the recording / reproduction mechanism 2.
The recording / playback mechanism 2 through the recording / playback head 32 of 0
The reproduction signal related to the double speed, which is dubbed and recorded on the cassette tape 46 of 0 at a double speed and is given to the reproduction signal changeover switch 28, is a high frequency component, for example, 8 to 10 kHz component among the frequency components included in the band pass filter 34. Only the data is taken out and given to the tape recorder control circuit 12.

The high frequency component contained in the double speed reproduction signal from the reproducing mechanism 2 given to the tape recorder control circuit 12 is stored in a memory (not shown) in the control circuit 12 (step 6). Such storage is continued for a predetermined time, for example, about 10 seconds, so that the reproduction signal from the cassette tape 10 of the reproducing mechanism 2 is recorded on the cassette tape 46 of the recording / reproducing mechanism 20 at a double speed for 10 seconds. The tape recorder control circuit 12 stores the high frequency components for 10 seconds at the double speed of the reproduction signal.

After this storage, the tape recorder control circuit 12 stops the driving of the cassette tapes 10 and 46 with respect to the reproducing mechanism 2 and the recording / reproducing mechanism 20 (step 7), and after this stop, the reproduction is performed. The motors 6 and 42 and the plungers 8 and 44 are driven to rewind the cassette tapes 10 and 46 of the mechanism 2 and the recording / playback mechanism 20, respectively (step 8). Next, the movable contacts 36c, 38c of the head changeover switch 22 are connected to the reproduction side contacts 36b, 38a of the reproduction signal recorded on the cassette tape 46 from the recording / reproduction mechanism 20 and the reproduction signal changeover switch 28 is used.
The movable contact 28c of the recording / reproducing mechanism 20 is switched to the contact 28b on the reproduction signal side (step 9), and the motor 42 of the recording / reproducing mechanism 20 is controlled by the tape recorder control circuit 12.
And the plunger 44 are controlled to drive the cassette tape 46 of the recording / playback mechanism 20 in the double speed playback mode (step 10). As a result, the reproduction signal in the cassette tape 10 of the reproducing mechanism 2 which was recorded on the cassette tape 46 of the recording / reproducing mechanism 20 is reproduced at double speed, and
The reproduction signal is applied to the bandpass filter 34 via the head changeover switch 22 and the reproduction equalizer 24, and further via the reproduction signal changeover switch 28. The reproduction signal relating to the cassette tape 46 of the recording / reproducing mechanism 20 given to the bandpass filter 34 is extracted from the high frequency components contained therein, and the high frequency components are stored in the memory of the tape recorder control circuit 12. Memorized in.

The tape recorder control circuit 12 records the high frequency component (reproduction high frequency component) in the reproduction signal from the cassette tape 10 of the reproduction mechanism 2 which was previously stored and the reproduction signal by double speed dubbing. The level of the high-frequency component (double-speed dubbing high-frequency component) stored this time in the reproduced signal from the cassette tape 46 of the recording / reproducing mechanism 20 that was reproduced later is compared (step 1).
1). When the double speed dubbing high frequency component level is not higher than the reproduction high frequency component level (NO), recording / recording is performed.
Since the level of the high frequency component of the reproduced signal recorded on the cassette tape 46 of the reproducing mechanism 20 by the double speed dubbing is lowered, the tape recorder control circuit 12 sets the level of its oscillation output to the bias oscillation circuit 30. When the double speed dubbing high frequency component level> the playback high frequency component level, the control is performed so that the high frequency component of the reproduction signal recorded at the double speed dubbing is corrected to the up direction (step 12). YES), contrary to the above,
The bias oscillating circuit 30 is controlled so that the level of its oscillation output is increased to correct the high frequency component of the reproduced signal recorded by the double speed dubbing in the down direction (step 13).

When the level setting of the bias oscillating circuit 30 is completed, the tape recorder control circuit 12 controls to rewind the cassette tapes 10 and 46 of the reproducing mechanism 2 and the recording / reproducing mechanism 20 (step 14). ),
Start double speed dubbing again (Step 1
5).

An example of varying the oscillation output level of the bias oscillation circuit 30 will be described with reference to FIG. 2. First, the reproduction signal from the cassette tape 10 of the reproducing mechanism 2 is recorded in the cassette of the recording / reproducing mechanism 20. When recording on the tape 46 by double speed dubbing, that is, the tape recorder control circuit 1 in step 6 from step 1 to step 5 described above.
When storing the high frequency components in the reproduced signal in 2,
The tape recorder control circuit 12 includes a bias oscillation circuit 30.
In response to this, an ON control signal of about 5V is output from OUT2 to turn on the switching transistor TR2. As a result, the voltage V1 represented by the following equation (1) is applied to the base of the switching transistor TR4.

V1 = [+ B / (ra + rb + rd + re)] × re (1) where + B is the power supply voltage, ra is the resistance value of the resistor Ra, and r
b is the resistance value of the resistor Rb, rd is the resistance value of the resistor Rd, and re
Is the resistance value of the resistance Re.

Therefore, the bias oscillation block OB
Is from the emitter of the switching transistor TR4 to the base of the switching transistor TR4 from V1.
It oscillates at an oscillation level in response to the voltage obtained by subtracting the voltage between the emitters, and the oscillation output of that level is output via the capacitor C. In this bias oscillation block OB, the oscillation output level rises when the input voltage rises, and the oscillation output level falls when it falls.

Next, as a result of the comparison in step 11,
When shifting to step 12, the tape recorder control circuit 12 outputs an ON control signal of about 5V from OUT3 to turn ON the switching transistor TR3. As a result, the voltage V2 represented by the following equation (2) is applied to the base of the switching transistor TR4.

V2 = [+ B / (ra + rb + rd + rf + rg)] × rg (2) where + B is the power supply voltage, rf is the resistance value of the resistor Rf, and r
g is the resistance value of the resistance Rg.

Therefore, the bias oscillation block OB
As a result, a voltage V2 lower than V1 in the equation (1) by a resistance of rf is applied, and as a result, the oscillation output level is lowered, and an output of a small oscillation output level is recorded / reproduced by the recording / reproducing mechanism 20. It is input to the head 32, and as a result,
The reproduction signal recorded by double-speed dubbing is corrected so that the high frequency component increases.

As a result of the comparison in step 11,
When shifting to step 13, the tape recorder control circuit 12 outputs an ON control signal of about 5V from OUT1 to turn ON the switching transistor TR1. As a result, the voltage V3 represented by the following equation (3) is applied to the base of the switching transistor TR4.

V3 = [+ B / (ra + rb + rc)] × rc (3) Here, + B is the power supply voltage, and rc is the resistance value of the resistor Rc.

Therefore, the bias oscillation block OB
As a result, a voltage V3 higher than the voltage V1 in the equation (1) by a resistance of rd is applied, and as a result, the oscillation output level is increased, and the output with a large oscillation output level is recorded / reproduced by the recording / reproduction mechanism 20. It is input to the head 32, and as a result,
The reproduction signal recorded by double-speed dubbing is corrected in the direction in which the high frequency components are down.

In this way, the tape recorder control circuit 12 corrects the bias oscillation input to the recording / reproducing head 32 so that the recording level of the high frequency component increases when it goes down, and the high frequency component when it goes up. Control is performed so that the recording level of becomes smaller.

[0040]

As described above, according to the present invention, the head of the recording / reproducing mechanism is switched to the recording side in the double speed dubbing mode by the head switching means, and the reproduction signal from the reproducing mechanism is recorded on the recording medium of the recording / reproducing mechanism. While recording with double speed dubbing
The reproduction signal switching means is switched to the reproduction signal side from the reproduction mechanism to obtain the high frequency component contained in the reproduction signal by the filter means, and this is given to the control means, and then,
The head switching means is switched to the reproducing side to output a reproduction signal reproduced by the head of the recording / reproducing mechanism, and this is input to the filter means via the reproduction signal switching means,
The filter means obtains a high frequency component included in the reproduction signal related to the double speed dubbing, supplies the high frequency component to the control means, and the control means compares the respective high frequency components and compares them. Is output to the bias oscillating means, and in the bias oscillating means, in response to the adjustment signal, the heads are selectively switched to give different levels of output, so that in the recording / reproducing mechanism. When the level of the high frequency component of the double-speed dubbed reproduction signal is down or up, the bias oscillation means can change its output level in response to the adjustment signal from the corresponding control means. , The recording medium in the recording / playback mechanism has the high frequency component of the playback signal adjusted to allow double speed dubbing, and it has excellent high frequency correction. To become.

[Brief description of drawings]

FIG. 1 is a circuit diagram including a recording / playback mechanism, a playback mechanism, a high-frequency correction circuit for double-speed dubbing according to an embodiment of the present invention, and peripheral circuits.

FIG. 2 is a detailed circuit diagram of the bias oscillation circuit of FIG.

FIG. 3 is a flowchart for explaining the operation.

[Explanation of symbols]

 2 playback mechanism 12 tape recorder control circuit 18 dubbing switch 20 recording / playback mechanism 22 head changeover switch 28 playback signal changeover switch 30 bias oscillating circuit 32 recording / playback head 34 bandpass filter

Claims (1)

[Claims] 1. The head of the recording / playback mechanism is switched to the recording side in the double speed dubbing mode and to the playback side in the high frequency correction mode. When the recording side is selected, the playback signal from the playback mechanism is output to the head. On the reproducing side, head switching means for outputting the reproduced signal reproduced by the head, bias oscillating means for selectively switching the output of different levels to the head in response to an adjustment signal, and a reproducing mechanism. Playback signal and the playback signal applied to the playback side via the head switching means in the switching state to selectively switch the playback signal to output to the filter means, and the playback signal switching means to switch and input. Of the frequency components included in the reproduced signal coming in, the filter means for obtaining a desired high frequency component, and the both reproduction signals given by the filter means Issue comparing respective high frequency components, speed dubbing for high frequency correction circuit characterized by comprising a control means for outputting an adjustment signal corresponding to the comparison to the bias oscillation means.