JPH06236502A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To lengthen the life of a rotary cylinder and to lengthen the life of a magnetic head as well by setting the rotary speed of the rotary cylinder to 1/N of its normal rotary speed. CONSTITUTION:Input information is once stored in a memory 105 prior to recording it in a magnetic tape by a magnetic head 115, and the rotary speed of the rotary cylinder 114 is set to 1/N (N is an integer of >=2) of the normal rotary speed. Then, a ratio of read speed to write speed in the memory 105 is set to 1/N. At the time of reproducing, a signal regenerated by the head 115 is once stored in the memory 105, an the rotary speed of the cylinder 114 is set to 1/N of the normal rotary speed, while the ratio of the read speed to the write speed in the memory 105 is set to N-times. As a result, the number of revolutions of the cylinder 114 is lowered to 1/N of that of the normal rotary speed, and hence the life of the head and the cylinder can be lengthened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing device (VTR) for monitoring purposes.

[0002]

2. Description of the Related Art In recent years, along with the widespread use of consumer VTRs, the spread of surveillance VTRs has been remarkably increasing as an application of the technology, forming a large market as a security market.

Under such circumstances, a VTR for security
As a result, recording is performed for a long time while performing intermittent recording (frame dropping recording). For example, PANASONIC VTR AG
In the -6720 etc., it is possible to record for 480 hours by using a tape capable of recording for 2 hours in the basic format. Depending on the monitoring status (system), the status can be as close as 24 hours a day, or 800
The record is close to 0 hours. Such a security VTR is required to have high reliability due to its character.

A conventional NTSC magnetic recording / reproducing apparatus will be described below. FIG. 2 is a block diagram of a conventional magnetic recording / reproducing apparatus. In FIG. 2, 201 is a video input terminal and 202 is an input buffer circuit. An image processing circuit 203 prepares for recording by performing FM modulation and the like. A recording / head amplifier 207 serves as a recording amplifier and supplies a recording current to the video head 215. Also, during reproduction, 207 becomes a head amplifier. Reference numeral 211 denotes a reproduced video processing circuit, which performs FM demodulation and the like. 212
Is an output video circuit, 213 is a video output terminal,
Output the video signal to the outside.

A rotating cylinder 214 rotates at 1800 rpm during recording and reproduction. 215 is a video head (magnetic head), which is a video tape (magnetic tape) 2
Record the video signal at 20. An operation display unit 222 gives a control instruction to the magnetic recording / reproducing apparatus and displays the current mode. 225 is an external control input terminal,
An external remote control input unit 223 receives a control signal from the outside. A system control unit 227 controls the entire system of the magnetic recording / reproducing apparatus. A drum servo control circuit 216 rotates the rotary cylinder 214 at 1800 rpm during reproduction and recording. A capstan servo control circuit 218 linearly or intermittently rotates the capstan motor 221 to linearly or intermittently feed the video tape 220.

Reference numeral 219 denotes an FG frequency dividing circuit, which changes the frequency dividing ratio in accordance with the video tape feeding speed.

With respect to the magnetic recording / reproducing apparatus having the above-mentioned structure, the relationship and operation of each component will be described below.
First, a conventional magnetic recording / reproducing apparatus will be described with reference to FIG.

In FIG. 2, the video input signal S201 is inputted to the video input terminal 201, and the input buffer circuit 20 is inputted.
2 and performs impedance conversion and AGC processing.
The output signal S202 of 202 is input to the video processing circuit 203 and subjected to FM modulation or the like to prepare for recording processing. 203
Output S203 is input to the recording / head amplifier 207,
The current is amplified and recorded on the video tape 220 by the video head 215. During reproduction, a reproduction signal is detected from 220 through 215 and amplified by the recording / head amplifier 207. Output signal S of recording / head amplifier 207
210 is input to the reproduced video processing circuit 211 and demodulates FM. The output signal S211 of 211 is input to the output video circuit 212, impedance-converted, and output from the video output terminal 213 as a video output signal S212.

An operation display unit 222 gives a control instruction to the magnetic recording / reproducing apparatus and displays the current mode. 225 is an external control input terminal. An external remote control input unit 223 receives a control signal from the outside. S222 is a control input signal which is input to 223.
S223 is an external control output signal which is output as a status to the external control output terminal. A system control unit 227 controls the entire system of the magnetic recording / reproducing apparatus.

The communication of each of 222, 223 and 227 is performed by the control bus line S221. Drum servo control circuit 2
Cylinder drive signal S21 during playback and recording at 16
Rotate 214 rotating cylinders through 6 at 1800 rpm. FG signal S224 for detecting the rotation speed of the cylinder and P for detecting the phase of the rotating cylinder 214
The G signal S214 is input to the drum servo control circuit 216 and forms a servo loop.

The capstan servo control circuit 218 makes the capstan motor 221 linearly rotate at a constant speed or intermittently rotates intermittently by the capstan drive signal S218 to linearly or intermittently feed the video tape 220. ing. The FG signal S219 for detecting the rotation speed of the capstan motor 221 is F
It is input to the G frequency dividing circuit 219, and at 219, waveform shaping and frequency division are performed according to various tape speeds. These frequency divisions are instructed by the system control unit 227 to the 219 via the bus line signal S217. The output signal S220 of 219 is input to the capstan servo control circuit 218 to form a servo loop. The system control unit 227, the drum servo control circuit 216, the FG frequency dividing circuit 219, and the capstan servo control circuit 218 communicate with each other by a bus line signal S217.

[0012]

However, in the above-described conventional magnetic recording / reproducing apparatus, the rotating cylinder is rotated at a high speed such as 1800 rpm, and particularly for long-time recording (time-lapse) magnetic recording / reproducing. The device (VTR) has a short life as a VTR due to wear of the bearing of the rotating cylinder and short life of the video head due to friction of the video tape.
There was a problem that maintenance had to be performed in a short period of time.

The present invention solves the above-mentioned problems. Magnetic recording / reproducing can extend the life of the rotary cylinder by reducing the wear of the bearing of the rotary cylinder, and extend the life of the video head due to the friction of the video tape. The purpose is to provide a device.

[0014]

In order to achieve the above object, the present invention comprises a tape transfer means for transferring a magnetic tape,
A rotary cylinder provided with a magnetic head, a cylinder drive unit for driving the rotary cylinder, and a memory means are provided.

[0015]

By the above means, 1. At the time of recording, the input information is temporarily stored in the memory means before being recorded on the magnetic tape by the magnetic head, and the rotation speed of the rotary cylinder is set to 1 / N (N is an integer of 2 or more) of the steady rotation speed. 1. Set the reading speed to the writing speed to the memory means to 1 / N. At the time of reproduction, the signal reproduced by the magnetic head is temporarily stored in the memory means, the rotation speed of the rotary cylinder is set to 1 / N of the steady rotation speed, and the read speed with respect to the write speed to the memory means is multiplied by N times. By setting it, the rotational speed of the rotary cylinder becomes as low as 1 / N of the steady rotational speed, and as a result, the life of the magnetic head and the rotary cylinder can be extended.

[0016]

DETAILED 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 of a magnetic recording / reproducing apparatus according to an embodiment of the present invention. In FIG. 1, 104 is an A / D
A conversion circuit that converts analog video signals into digital signals. A digital memory circuit 105 temporarily stores the digitally converted video signal. A D / A conversion circuit 106 converts a digital signal into an analog signal. A recording / head amplifier 107 supplies a recording signal to the rotating cylinder 114 as a recording amplifier, and the video head 115 records the video signal on the video tape 120. At the time of reproduction, 107 serves as a head amplifier to amplify a minute signal. An A / D conversion circuit 108 converts an analog signal into a digital signal. Digital memory circuit 10
Reference numeral 5 temporarily stores a digital signal during reproduction. A D / A conversion circuit 110 converts a digital signal into an analog signal.

Reference numeral 114 is a rotary cylinder. Reference numeral 116 is a drum servo control circuit. Reference numeral 126 is an FG frequency dividing circuit. 114, 116 and 126 form a drum servo control loop. Reference numeral 118 is a capstan servo control circuit. Reference numeral 119 is an FG divider circuit. 121 is a capstan motor. A loop of a capstan servo is formed by 118, 119 and 121.

The blocks other than the above in FIG. 1 are shown in FIG.
The description is omitted because it is the same as the above.

With respect to the magnetic recording / reproducing apparatus having the above-described structure, the relationship and operation of each constituent element will be described below. A
The video signal input to the D / D conversion circuit 104 is converted into a digital signal S104 and the digital memory circuit 105
Is input to and stored in. The output S105 of 105 is D /
The A conversion circuit 106 converts the analog signal. At this time, due to the difference between the speed written in the digital memory circuit 105 and the speed read out, the converted rate is set to a rate having a correlation with the speed of the rotating cylinder during recording. That is, in the case of a rotating cylinder with a normal rotation of 1800 rpm (basic format), the
When it is set to 00 rpm, the frequency of the read clock is set to 1/2 of the frequency of the write clock of the digital memory circuit 105. During normal recording, the frequency ratio between the write clock and the read clock is 1: 1. The relationship is shown below.

Cylinder rotation speed (rpm) Write clock: read clock frequency ratio 1800 1: 1 900 2: 1 90 20: 1 45 40: 1 106 S 106 converted into analog is the recording circuit 107.
Is input to the rotary cylinder 114 and is recorded on the video tape 120 by the video head 115.

During reproduction, the signal reproduced by the video head 115 is amplified by 107 and becomes an amplified signal S107, which is input to the A / D conversion circuit 108. The digital signal S108 converted into a digital signal in 108 is input to the digital memory circuit 105 and temporarily stored by the write clock. In 105, the signal stored by the read clock is read out, and the digital signal 109 is read by the D / A conversion circuit 11
At 0, it is converted into an analog signal. The ratio of the rotation speed of the rotating cylinder and the frequency of the write clock: read clock during reproduction is shown below.

Cylinder rotation speed (rpm) Write clock: Read clock frequency ratio 1800 1: 1 900 1: 2 90 1:20 45 1:40 In the digital memory circuit 105, what is the video signal unless the data on the writing side changes. The same signal can be read again.

Reference numeral 114 is a rotating cylinder. 114 normally rotates at 1800 rpm, but according to this method, 900
Low speed rotation such as rpm, 90 rpm and 45 rpm is performed. A drum servo control circuit 116 controls the cylinder servo circuit. Reference numeral 126 is an FG frequency dividing circuit, which divides the frequency of the FG signal S124 which is the rotation information of the rotary cylinder 114. This FG signal S124 is used as it is when the rotary cylinder 114 rotates at a low speed, and is divided at a frequency division ratio according to the speed at a high speed rotation. S114
Is a PG signal for detecting the phase of the rotating cylinder 114. It is input to 126 as in S124. S115 is a signal resulting from the frequency division and is input to 116. The rotary cylinder 114 is connected via the drum servo control circuit 116.
It is controlled and driven by the drive signal S116.

Reference numerals 114, 116 and 126 form a drum servo control loop. Reference numeral 118 is a capstan servo control circuit. The drive signal S118 controls and drives the capstan motor 121. 119 is FG
It is a frequency divider. The division ratio is changed according to the rotation speed of the capstan motor. S119 is an FG signal for detecting the rotation speed of the capstan motor and is input to 119. S120 is a signal resulting from the frequency division and is input to the capstan servo control circuit 118. 11
8, 119 and 121 form a capstan servo loop.

In the capstan circuit, the capstan motor 121 can be rotated linearly or stepwise in a normal manner to perform intermittent feeding. 126, 116, 119, 118
The system control unit 127 controls the control bus signal S117 so that the frequency division ratios of the FG frequency dividing circuits 126 and 119 are 114
And 121 for low speed and high speed control and 121 for linear feed or intermittent feed control. Further, during intermittent feeding, it is possible to finely adjust the feeding speed of the tape to perfectly match the inclination angle recorded on the tape.

As described above, according to the magnetic recording / reproducing apparatus of the embodiment of the present invention, the tape transfer means for transferring the magnetic tape, the rotary cylinder provided with the magnetic head, and the cylinder drive section for driving the rotary cylinder are provided. And a memory means for temporarily storing the input information by the magnetic head before recording it on the magnetic tape. During recording, the rotational speed of the rotary cylinder is 1 / N of the steady rotational speed (N is a positive integer). ), And the read speed with respect to the write speed of the memory is set to 1 / N.
The magnetic tape is intermittently transferred by the tape transfer means, the rotating cylinder is provided with a frequency generator whose frequency changes in accordance with the rotation speed, and the cylinder driving unit divides the output signal of the frequency generator. A frequency dividing circuit is provided for controlling the rotation speed of the rotary cylinder by the output of the frequency dividing circuit. During recording, the tape transfer speed of the tape transferred by the tape transfer means is a constant speed of 1
By setting it to / N, the tape is intermittently fed and the rotating cylinder rotates at a lower speed than the basic format, but both the cylinder speed and tape speed are 1 /
Since the track inclination angle is equal to N, the track inclination angle is equal to that of the basic format. Further, since the relative speed between the head and the tape and the recording rate are both 1 / N, the recording wavelengths are equal, and as a result, recording is performed in compliance with the basic recording format. it can.

By doing so, the wear of the bearing of the rotary cylinder is reduced, and the life of the video head and the life of the rotary cylinder are extended due to the friction of the video tape. As a result, it is possible to provide a magnetic recording / reproducing apparatus that can dramatically reduce service maintenance and prolong the service life.

[0029]

As is apparent from the above description of the embodiments, according to the present invention, by setting the rotation speed of the rotary cylinder to 1 / N of the steady rotation speed, the life of the rotary cylinder becomes longer and It is possible to provide a magnetic recording / reproducing device in which the life of the magnetic head is extended due to the friction of the tape.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram showing a configuration of a conventional magnetic recording / reproducing apparatus.

[Explanation of symbols]

 104 A / D conversion circuit 105 Digital memory circuit 106 D / A conversion circuit 107 Recording / head amplifier 108 A / D conversion circuit 110 D / A conversion circuit 114 Rotating cylinder 115 Video head 116 Drum servo control circuit 126 FG frequency dividing circuit 127 System control unit 118 Capstan servo control circuit 119 FG frequency divider circuit 120 Video tape 121 Capstan motor

Claims (8)

[Claims] 1. A tape transfer means for transferring a magnetic tape, a rotary cylinder equipped with a magnetic head, a cylinder drive unit for driving the rotary cylinder, and before input information is recorded on the magnetic tape by the magnetic head. And a memory means for storing once, and at the time of recording, the rotation speed of the rotary cylinder is 1 / N (N is 2) of the steady rotation speed.
A magnetic recording / reproducing apparatus in which the reading speed with respect to the writing speed to the memory means is set to 1 / N. 2. The magnetic recording / reproducing apparatus according to claim 1, wherein during recording, the transfer speed of the magnetic tape transferred by the tape transfer means is set to 1 / N of the steady speed. 3. The magnetic recording / reproducing apparatus according to claim 1, wherein the magnetic tape is intermittently transferred by the tape transfer means during recording. 4. The rotating cylinder according to any one of claims 1 to 3, wherein the rotating cylinder is provided with a frequency generator whose frequency changes in accordance with a rotation speed, and further, an output signal of the frequency generator is supplied to a cylinder driving section. A magnetic recording / reproducing apparatus provided with a frequency dividing circuit for controlling the rotation speed of the rotary cylinder by the output of the frequency dividing circuit. 5. A tape transfer means for transferring a magnetic tape, a rotary cylinder equipped with a magnetic head, a cylinder drive unit for driving the rotary cylinder, and a memory for temporarily storing a signal reproduced by the magnetic head. Means for setting the rotation speed of the rotary cylinder to 1 / N (N is an integer of 2 or more) of the steady rotation speed during reproduction, and multiplying the reading speed with respect to the writing speed to the memory means by N times. A magnetic recording / reproducing device that is set. 6. The magnetic recording / reproducing apparatus according to claim 5, wherein during reproduction, the transfer speed of the magnetic tape transferred by the tape transfer means is set to 1 / N of the steady speed. 7. The magnetic recording / reproducing apparatus according to claim 5, wherein the magnetic tape is intermittently transferred by the tape transfer means during reproduction. 8. The rotating cylinder according to claim 5, wherein the rotating cylinder is provided with a frequency generator whose frequency changes in accordance with the rotation speed, and the cylinder driving unit receives an output signal of the frequency generator. A magnetic recording / reproducing apparatus provided with a frequency dividing circuit for controlling the rotation speed of the rotary cylinder by the output of the frequency dividing circuit.