JPH04341902A - Magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To keep the quantity of the sound signal of the deep layer of a tape within a prescribed range against the change of various conditions by controlling the recording current of a first or a second head so that the signal quantity of the prescribed range of the signal of the deep layer or the surface layer of the tape by the first or the second recording head is detected. CONSTITUTION:When the tape 19 is set in a device, and the device is turned into a recording mode, a switch 20 is switched to a terminal (a) side, and the sound signal inputted from an input terminal 2 is inputted to a rotary head 7 for a sound through a change-over switch 3, a noise reduction circuit 4, an FM modulator 5, a sound recording amplifier 6, and the switch 20, and the sound signal is recorded in the deep layer part of the tape 19. On the other hand, a TV video signal inputted from the input terminal 10 is inputted to the head 14 through the switch 11, a processing circuit 12, and an amplifier 13, and the video signal is recorded in the surface layer part of the tape 19. At that time, the sound/video signal picked up by the head 7 is inputted to a control circuit 8 through the amplifier 17 and a detection circuit 18, and controls the recording current of the heads 7, 14 so that the signal quantity within the prescribed range of the deep layer part/surface layer part of the tape is detected.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording and reproducing apparatus for deep recording audio signals on video tracks.

0002

2. Description of the Related Art Conventionally, in this type of magnetic recording and reproducing apparatus, both a video signal and an audio signal are recorded on the same video track of the same tape using a rotating head, and the recording system has a configuration as shown in FIG. have. That is, the audio signal input from the television audio input terminal 2 is subjected to noise reduction processing by the noise reduction circuit 4 via the input changeover switch 3, and then input to the FM modulator 5 where it is frequency modulated. This frequency-modulated audio signal is amplified by an audio recording amplifier 6 and then deep-recorded onto a tape 19 by an audio rotary head 7. On the other hand, the video signal input from the television video signal input terminal 2 is input to the video signal recording processing circuit 12 via the changeover switch 3, where it is subjected to various processing, and then amplified by the video recording amplifier 13. The image is recorded on the surface layer of the tape 19 by the video rotating head 14. At this time, among the audio signals recorded by the audio rotary head 7, the signals near the surface of the tape 19 are erased later along with the recording of the video signal by the video rotary head 14. However, as one goes deeper into the tape 19, the audio signal remains without being erased. Note that 15 is a tape running cylinder system control circuit for running the tape 19 and controlling the scanning of the rotary heads 7 and 14.

FIG. 8 is a block diagram showing a reproducing system of the magnetic recording/reproducing apparatus. The audio signal recorded in the deep part of the tape 19 is picked up by the audio rotating head 7,
The picked up audio signal is amplified by the audio preamplifier 17, demodulated by the FM demodulator 21, subjected to noise reduction processing by the noise reduction circuit 22, and then outputted to the outside from the audio output terminal 23. . A video signal recorded near the surface of the tape 19 is picked up by a video rotary head 14, and after being amplified by a video preamplifier 24, it is input to a video reproduction processing circuit 25. The video signal reproduction processing circuit 25 performs various reproduction processing on the input video signal, and then outputs it to the outside from the video output terminal 26. Note that 15 is a tape running cylinder system control circuit for running the tape 19 and controlling the scanning of the rotary heads 7 and 14. As mentioned above, the audio signal remaining in the deep part of the tape 19 is picked up and played back by the audio rotating head 7, but the amount of the audio signal is the same as the amount of audio signal erased from the tape by the video rotating head during recording. It becomes dependent.

[0004] Therefore, in a magnetic recording/reproducing apparatus employing the above method, depending on the magnetic characteristics of the tape used and the head conditions (the magnitude of the recording current), when a video signal is recorded on the surface layer of the tape, it may be The amount of audio signal remaining in the audio signal changes, and in the worst case, problems occur such as sound breakage during playback or the audio signal in the deep layer being erased to the extent that the sound quality deteriorates. Furthermore, even when the same tape is recorded, the amount of audio signals remaining in the deeper layers of the tape may change when video signals are recorded on the surface layer of the tape, depending on the ambient temperature at the time of recording, resulting in similar problems. .

[0005]

[Problems to be Solved by the Invention] As mentioned above, in a magnetic recording/reproducing device that deep-records an audio signal along with a video signal on the same track of a tape, the magnetic characteristics of the tape used and the head conditions (the magnitude of the recording current) )), when the video signal is recorded on the surface layer of the tape, the amount of audio signal remaining in the deeper layer changes, and in the worst case, the sound quality may deteriorate during playback, or the amount of audio signal remaining in the deeper layer may change. A problem occurs in which the audio signal of the section is erased. Furthermore, even when the same tape is recorded, the amount of audio signals remaining in the deeper layers of the tape may change when video signals are recorded on the surface layer of the tape, depending on the ambient temperature at the time of recording, resulting in similar problems. .

The present invention aims to eliminate the above-mentioned drawbacks by keeping the amount of audio signals remaining in the deep part of the tape within a predetermined range even if various conditions such as the ambient temperature and magnetic properties of the tape change. The purpose of the present invention is to provide a magnetic recording/reproducing device that can perform the following functions. [Structure of the invention]

[0007]

[Means for Solving the Problems] The present invention provides that after a first recording head records a first signal in a deep portion of a magnetic tape,
In a magnetic recording/reproducing device in which a second recording head records a second signal on the surface layer of the magnetic tape, the recording current when recording the first signal by the first recording head is A recording current variable means for changing the recording current, a signal amount detecting means for detecting the first signal amount recorded in the deep layer of the magnetic tape, and a signal amount within a predetermined range is detected by the signal amount detecting means. and recording current control means for controlling the recording current of the first recording head via the recording current variable means so as to control the recording current of the first recording head. As another configuration of the present invention, after the first recording head records the first signal in the deep layer of the magnetic tape, the second recording head records the second signal on the magnetic tape. In the magnetic recording/reproducing device for recording on a surface layer, the second recording head is operated by the second recording head.
recording current variable means for changing the recording current when recording the signal; signal amount detection means for detecting the amount of the first signal recorded in the deep layer of the magnetic tape; and the signal amount detection means and recording current control means for controlling the recording current of the second recording head via the recording current variable means so that a signal amount within a predetermined range is detected.

In yet another configuration of the present invention, after the first recording head records the first signal in the deep layer of the magnetic tape, the second recording head records the second signal in the magnetic tape. In a magnetic recording/reproducing apparatus for recording on a surface layer of a tape, a first recording current variable means for changing a recording current when recording the first signal by the first recording head; a second recording current variable means for changing the recording current when recording the second signal by the recording head; and detecting the amount of the first signal recorded in the deep layer of the magnetic tape. controlling the recording current of the first recording head via the first recording current variable means such that the signal amount detection means detects a signal amount within a predetermined range; The recording current control means controls the recording current of the second recording head via the second recording current variable means.

[0009]

In the magnetic recording/reproducing apparatus of the present invention, the recording current variable means changes the recording current when the first recording head records the first signal. The signal amount detection means detects the first signal amount recorded in the deep layer of the magnetic tape. The recording current control means controls the recording current of the first recording head via the recording current variable means so that the signal amount detection means detects a signal amount within a predetermined range.

As another feature of the present invention, in the magnetic recording/reproducing apparatus, the recording current variable means changes the recording current when the second recording head records the second signal. The signal amount detection means detects the first signal amount recorded in the deep layer of the magnetic tape. The recording current control means controls the recording current of the second recording head via the recording current variable means so that the signal amount detection means detects a signal amount within a predetermined range. As yet another feature of the present invention, in the magnetic recording/reproducing apparatus, the first recording current variable means changes the recording current when the first recording head records the first signal. The second recording current variable means changes the recording current when the second recording head records the second signal. The signal amount detection means detects the first signal amount recorded in the deep layer of the magnetic tape. The recording current control means controls the recording current of the first recording head via the first recording current variable means so that the signal amount detection means detects a signal amount within a predetermined range. The second recording current variable means
control the recording current of the recording head.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the magnetic recording/reproducing apparatus of the present invention. 1 is an audio line input terminal for inputting audio line signals, 2 is an input terminal for television audio signals, 3 is a changeover switch for switching input terminals 1 and 2,
4 is a noise reduction circuit that performs noise reduction processing on the audio signal, and 5 is an FM that performs frequency modulation on the audio signal.
A modulator 6 is an audio recording amplifier that amplifies the modulated audio signal and outputs it to the audio rotary head 7; 7 is an audio rotary head that records the frequency-modulated audio signal on tape; 8
1 is a recording current control circuit that controls a recording current when recording an audio signal with the audio rotary head 7; 9 is a video line input terminal for inputting a video line signal; 10 is a video input terminal for inputting a television video signal; 11 is an input terminal 9, 1
12 is a video signal processing circuit that performs various processing on the input video signal; 13 is a video recording amplifier that amplifies the video signal and outputs it to the video rotary head 14; 14 is the video signal that is transferred to the tape 19. 15 is a rotating head 7 for running and rotating a tape 19;
14 is a tape running and cylinder system control circuit that controls the scanning; 16 is a recording/playback operation control device that controls the recording and playback operations of the device; 17 is an audio unit that amplifies the audio/video signal picked up by the audio rotary head. A preamplifier, 18 a reproduction signal amount detection circuit for detecting the amount of audio signal picked up by the audio rotary head 7, and 20 a switch for switching between a recording system and a reproduction system.

Next, the operation of this embodiment will be explained. After setting the tape 19 in the device, when the device is set to recording mode, the switch 20 is switched to the terminal a side, and the audio signal inputted from, for example, the television audio input terminal 2 is passed through the input selector switch 3 to the noise reduction circuit 4. is input. The audio signal that has undergone noise reduction processing in the noise reduction circuit 4 is frequency modulated in the FM modulator 5, and then amplified by the audio recording amplifier 6.
This is input to the audio rotary head 7 via the switch 20. At this time, the amplification degree of the audio recording amplifier 6 is appropriate. The audio rotary head 7 records the modulated audio signal in the deep part of the tape 19. At the same time, a television video signal is input from the television video input terminal 10, and this video signal is input to the video signal recording processing circuit 12 via the switch 11, where it is subjected to various processing. It is output to the video recording amplifier 13. The video recording amplifier 13 amplifies the input video signal and outputs it to the video rotary head 14, thereby recording the video signal on the surface layer of the tape 19. Incidentally, in the tape 19, a portion indicated by a indicates an audio signal recording portion, and a portion indicated by b indicates a video signal recording portion.

Such a recording operation is performed in step 20 of FIG.
After the period indicated by 1, recording of the audio and video signals is stopped. Next, as shown in step 202 of FIG. 2, the tape 19 is rewound to the point at which recording started, and then, as shown in step 203, the tape 19 is set to playback mode. At this time, the switch 20 is switched to the terminal b side. The audio FM signal picked up by the audio rotary head 7 in this reproduction mode is amplified by the audio preamplifier 17 and then input to the reproduction signal amount detection circuit 18. The reproduced signal amount detection circuit 18 is TA8.
An output for a tracking meter such as 768N is used, and its output potential increases as the number of audio signals picked up by the audio rotary head 7 increases. The output potential of the reproduced signal amount detection circuit 18 is smoothed by a capacitor C and then input to the recording current control circuit 8. The recording current control circuit 8 controls the audio recording amplifier 6 according to the input potential.
change the gain. That is, when the input potential is low, it is assumed that the amount of deeply recorded audio signals remaining on the tape 19 is small, and the gain of the audio recording amplifier 6 is increased. When the above playback is performed within the range shown in step 203, after rewinding the tape and bringing the tape to the recording start position, a setting completion signal 100 is sent from the playback signal amount detection circuit 18.
This recording operation control circuit 16 controls the tape running cylinder system control circuit 1 until the
5 to repeat the operations of steps 201 to 204 shown in FIG. In this way, when the gain of the audio recording amplifier 6 is adjusted so that the amount of audio signals recorded in the deep part of the tape 19 picked up by the audio rotary head 7 falls within a predetermined range, that is, when recording When the recording current of the audio rotary head 7 is set appropriately (corresponding to the input of the setting completion signal 100), the previous recording re-operation is completed and a full-scale recording mode is entered.

FIG. 3 shows the reproduced signal amount detection circuit 1 shown in FIG.
8 is a block diagram showing a specific configuration example of the recording current control circuit 8 and the audio recording amplifier 6. FIG. Reproduction signal amount detection circuit 1
Numeral 8 is an audio carrier detection circuit 181 that outputs a potential corresponding to the amount of audio signal recorded in the deep layer, and this potential is output to the recording current control circuit 8 via a switch 182. The signal is input to comparators 183 and 185. Comparators 183 and 184 compare the input potential with reference voltages V1 and V2, respectively, and when the input potential is between voltages V1 and V2, a high level setting completion signal 100 is output from the AND gate 46. It is output to the recording/reproducing operation control circuit 16. On the other hand, the recording current control circuit 8
consists of an operational amplifier 81 and a comparator 82, and the potential amplified by the operational amplifier 81 is input to the inverting input terminal of the comparator 82. Further, a reference voltage VF obtained by dividing the voltage VCC by resistors R7 and R8 is input to the non-inverting input terminal of the comparator 82. Therefore, the comparator 82 compares the voltage input from the operational amplifier 81 with the reference voltage VF, and if the input voltage is lower than the reference voltage VF, the output voltage is increased in inverse proportion to the input voltage. Further, when the input voltage is higher than the reference voltage VF, the comparator 82 sets its output to a low level, and the transistor TR of the audio recording amplifier 6
Turn off. Therefore, when the potential output from the reproduced signal amount detection circuit 18 is low, the transistor TR increases its collector current and increases the gain of the amplifier 61 for amplifying the modulated audio signal constituting the audio recording amplifier 6. Here, if the configuration of the audio recording amplifier 6 is as shown in the figure,
The gain of this amplifier 61 is (R3+RX+R2)/(
R3+RX), and when transistor TR is off, the gain is the lowest, and at this time RX=(R3+R4+R2
)/(R3+R4). However, R3<R1<(R3
+R4), where RX indicates the combined resistance value of resistor R4 and transistor TR. Further, when the gain is maximum, the transistor TR is on, and at that time, RX=(R3+R2)/R3. Therefore, the potential output from the reproduced signal amount detection circuit 18 is
The gain of the audio recording amplifier 6 is adjusted by the recording current control circuit 8 until it is determined in steps 1 and 82 that the voltage is between V1 and V2.

According to this embodiment, the recording current of the audio rotary head 7 is set appropriately during recording, and even after the video signal is recorded by the video signal rotary head 14, the tape 1
It is possible to automatically adjust so that an appropriate amount of audio signal remains in the deep part of the sound. Therefore, it is possible to always reproduce high quality audio by preventing the reproduced audio signal from being broken or the sound quality from being deteriorated due to the magnetic performance of the tape used or the ambient temperature.

FIG. 4 is a diagram showing an example of a recording current control circuit 8, a reproduced signal amount detection circuit 18, and an audio recording amplifier showing another embodiment of the present invention. The recording current control circuit 8 of this example is mainly composed of a counter 41.
A switching pulse is input to the clock terminal (14) of the circuit, and each time the switching pulse is input, its output terminals (2), (4), . . . (9), and (11) become high level in sequence. As a result, the resistor R4/9 for changing the gain of the amplifier 61 of the audio recording amplifier 6 is sequentially switched, and the gain of the amplifier 61 is sequentially increased. or,
When a high level signal is input to the terminal (13) of this counter 41, even if a clock is input to the terminal (14),
The output levels of the output terminals (2), (4), . . . (9), and (11) do not change and are fixed at the immediately previous output level.

First, when setting the recording current of the audio recording amplifier 6, switch S is turned on before recording audio and video signals.
2 to terminal b, and as shown in step 501 of FIG. 5, when starting the recording operation, the switch S1 is momentarily turned on in step 502. As a result, the counter 41
Reset. After that, the terminal (14) of the counter 41
When a clock is input to the output terminals (2), (4)...(9), (11) as shown in step 503 of FIG.
) becomes high level sequentially, and steps 504 to 5 in FIG.
As shown in 06, transistors TR1, TR2,...T
R9 turns on in turn. At this time, since the clock uses a switching pulse (30 Hz), the gain of the amplifier 61 of the audio recording amplifier 6 increases every two tracks. In this way, when the output terminal (11) of the counter 41 changes from high level to low level, recording is stopped and rewinding is performed as shown in step 507 of FIG.
Next, the playback operation starts from the recording start portion.

During reproduction, switch S2 is switched to terminal a. At the start of playback shown in step 508 of FIG. 5, after turning on the switch S1 for a moment and resetting the counter 41,
This counter 41 starts counting. counter 41
is its output terminal (2) as the clock is input,
(4)...(9) and (11) are counted up (high level) in synchronization with the recording position, and transistor TR1
~TR9 are turned on sequentially as shown in steps 509 and 510. On the other hand, when the reproduced signal amount detection circuit 18 obtains a deep audio signal of an appropriate size, the gate 185
The output becomes high level and is inputted to the terminal (13) of the counter 41 via the gate 42 and switch S2 as shown in step 511 of FIG. In this way, when the terminal (13) of the counter 41 changes from low to high level, the count-up operation of the counter 41 is stopped and the output signal state is maintained to set the amplification factor of the amplifier 61 to obtain an appropriate deep audio signal. . That is, at this time, all of the transistors TR1 to TR9 are off, or one of them is on. The gate 1 of the reproduced signal amount detection circuit 18
Since the output signal from 85 is also input to the recording and reproducing operation control circuit 16 shown in FIG. 1, the reproducing operation of the apparatus is stopped at this point and is rewound to the recording start portion in step 512 of FIG. Thereafter, the switch S2 is switched to the terminal c, and since the terminal (13) remains at the high level during subsequent recording and playback, the output state of the counter 41 is maintained as it was at the time of the setting. This example also has the same effect as the previous example.

FIG. 6 is a block diagram showing a detailed example of the recording current control circuit 8 and the video recording amplifier 13 constituting another embodiment of the present invention. In this example as well, the recording current control circuit 8 performs the same operation as that shown in FIG.
is counted up and the output terminals (2), (4)...(9
) and (11) sequentially become high level, turning on transistors TR9 to TR1. Therefore, contrary to the embodiment shown in FIG. 4, the counter 41 counts up, so that control is performed such that the gain of the amplifier 131 of the video recording amplifier 13 is sequentially decreased. When an appropriate amount of deep audio recording signal is detected in the counter 41, the counting operation of the counter 41 is stopped, the gain of the video recording amplifier 31 is set, and the amount of the deep audio recording signal is adjusted to the extent that an appropriate deep audio signal remains. At the recording current, the recording current is set so that the video rotary head 14 records the video signal on the tape 19. Therefore, this example also has the same effect as the previous example.

It is also possible to provide a dedicated switch for setting the recording current during recording as described above, and to set the recording current automatically only when the user turns on the dedicated switch. Since the time required to automatically set the recording current is approximately 0.3 seconds for recording and 0.3 seconds for reproduction, operability will not deteriorate even if the configuration is such that it is always performed at the start of recording. In addition, in the embodiment of FIG. 1, the recording current control circuit 8 is configured to control the gains of both the audio recording amplifier 6 and the video recording amplifier 13 to appropriately control the amount of audio signal recorded in the deep part of the tape 19. Also good. Further, in the above embodiments, the present invention is applied to a video tape recorder that records audio signals deeply, but it can also be applied to any device that records signals deeply on a floppy disk or the like to obtain the same effect. can.

[0021]

As described above, according to the magnetic recording and reproducing apparatus of the present invention, even if various conditions such as the ambient temperature and the magnetic properties of the tape change, the amount of audio signals remaining in the deep part of the tape can be controlled within a predetermined range. It can be done.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a magnetic recording/reproducing apparatus of the present invention.

FIG. 2 is a diagram illustrating a recording current setting operation of the audio rotary head in the apparatus shown in FIG. 1;

FIG. 3 is a circuit diagram showing detailed examples of the recording current control circuit, reproduction signal amount detection circuit, and audio recording amplifier shown in FIG. 1;

FIG. 4 is a circuit diagram showing another embodiment of the recording current control circuit, reproduction signal amount detection circuit, and audio recording amplifier shown in FIG. 1;

5 is a diagram illustrating a recording current setting operation in another embodiment shown in FIG. 4. FIG.

FIG. 6 is a block diagram showing an embodiment of a recording current control circuit and a video recording amplifier according to another embodiment of the present invention.

FIG. 7 is a block diagram showing an embodiment of a recording system of a conventional magnetic recording/reproducing device.

FIG. 8 is a block diagram showing an embodiment of a reproducing system of a conventional magnetic recording/reproducing device.

[Explanation of symbols]

4...Noise reduction circuit 5...FM modulator 6...Audio recording amplifier 7... Rotating head for audio 8... Recording current control circuit 12...Video signal recording processing circuit 13...Video recording amplifier 14...Rotating head for video 15...Tape travel cylinder system control circuit 16...Recording/reproducing operation control circuit 17...Audio preamplifier 18...Reproduction signal amount detection circuit

Claims (3)

[Claims] Claim 1: After a first recording head records a first signal in a deep layer of a magnetic tape, a second recording head records a second signal.
In the magnetic recording and reproducing apparatus for recording a signal on the surface layer of the magnetic tape, a recording current variable means for changing a recording current when recording the first signal by the first recording head; a signal amount detection means for detecting a first signal amount recorded in a deep layer of the magnetic tape; and a recording current variable means so that the signal amount detection means detects a signal amount within a predetermined range. 1. A magnetic recording/reproducing apparatus comprising: a recording current control means for controlling a recording current of the first recording head through the magnetic recording head. 2. After the first recording head records the first signal in the deep layer of the magnetic tape, the second recording head records the second signal.
In the magnetic recording and reproducing apparatus for recording a signal on the surface layer of the magnetic tape, a recording current variable means for changing a recording current when recording the second signal by the second recording head; a signal amount detection means for detecting a first signal amount recorded in a deep layer of the magnetic tape; and a recording current variable means so that the signal amount detection means detects a signal amount within a predetermined range. 1. A magnetic recording/reproducing apparatus comprising: a recording current control means for controlling a recording current of the second recording head via the magnetic recording head. 3. After the first recording head records the first signal in the deep layer of the magnetic tape, the second recording head records the second signal.
In the magnetic recording/reproducing apparatus for recording a signal on the surface layer of the magnetic tape, a first recording current variable means for changing a recording current when recording the first signal by the first recording head. a second recording current variable means for changing the recording current when recording the second signal by the second recording head; a signal amount detection means for detecting a signal amount; and a signal amount detection means for detecting a signal amount; A magnetic recording/reproducing apparatus comprising: a recording current control means for controlling a current and a recording current of the second recording head via the second recording current variable means.