JPH05182310A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To stably reproduce a signal in either case by changing the relative speed of a rotary head to the recording track direction on a magnetic tape in the case of normal reproducing and in the case of search reproducing respec tively. CONSTITUTION:In the device capable of scanning in a slant direction to the longitudinal direction of the magnetic tape 23 by the rotary heads 22A and 22B, the rotation of a rotary drum 21 is controlled to make the relative speed of the heads 22A and 22B to the recording track direction on the tape 23 a 1st speed RHN at the time of normal speed reproducing of the tape 23. Then, at the time of search reproducing under fast forwarding and rewinding of the tape 23 at a higher speed than the normal, the rotation of the drum 21 is controlled to make the relative speed of the heads 22A and 22B to the tape 23 a 2nd speed RHS. By this method, the stable signal can be reproduced in either case of the normal reproducing and the search reproducing.

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Field of Industrial Application Conventional Techniques Problems to be Solved by the Invention Means for Solving the Problems (FIG. 1) Operation (FIG. 1) Embodiment (1) Overall Configuration of DAT (FIG. 2) (2) DAT (FIG. 1) (3) Other Examples Effect of Invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus, for example, a digital audio tape recorder (DA).
It is suitable for application to T).

[0003]

2. Description of the Related Art Conventionally, a rotary head type digital audio tape recorder (hereinafter referred to as DAT) has been used as a tape recorder device capable of high-density recording of audio signals. In this DAT, an input audio signal can be recorded on or reproduced from a magnetic tape wound around the drum at a predetermined winding angle by using a rotating head arranged on the drum.

In the DAT, the running speed of the magnetic tape and the rotation of the drum are servo-controlled so that the relative speeds of the magnetic tape and the rotary head in the track direction are constant. Here, instead of the normal reproduction, in the so-called search reproduction in which the time of the subcode is reproduced while fast-forwarding or rewinding the magnetic tape, the feeding speed of the magnetic tape is high, and therefore the drum speed of the normal reproduction is Relative speed changes compared to normal playback.

When the relative speed changes in a wide range in practice,
Since the circuits of the reproduction system such as the reproduction amplifier circuit, the equalizer, and the phase locked loop (PLL) support a constant rate, the signal itself may not be readable. Therefore, during search playback, change the drum rotation speed,
As a result, the relative speed is kept constant as in normal reproduction.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In AT, the relative speed when using a conventional drum with a diameter of 30 [mmφ] is selected to be 3.13 [m / S].
When a small drum with a diameter of 15 [mmφ] is used, the relative speed is halved to 1.57 [m / S].

In addition, instead of the small drum of 15 [mmφ],
To reduce the size of the entire drum peripheral device, including the motor,
There is a DAT that is designed to use a small drum with a diameter of 18 [mmφ].

[Equation 1] The value is represented by.

In this case, the reproduction amplifier circuit, the equalizer, the PLL, etc. in the DAT having a diameter of 15 [mmφ] are used as they are, and the normal speed can be stably reproduced with the relative speed kept constant. However, in this way, the fluctuation of the relative speed during search playback becomes larger than that during normal playback, and when normal playback is performed at the upper limit rate of the 20% margin in the playback system, the relative speed deviates. May occur.

As described above, when the relative speed is out of the margin range of the equalizer, the frequency characteristic of the reproduced signal fluctuates, and when the relative speed is out of the lock range of the PLL, the reproduced clock cannot be obtained and the signal cannot be reproduced. There is.

When the lock range of the PLL is widened,
The so-called pseudo-lock is likely to occur, and on the contrary, if it is narrowed, it becomes weak against the fluctuation of the relative speed, and in consideration of these, the rock range is selected within the range of ± 10% to ± 20%.

In the DAT, the running speed of the magnetic tape and the rotating speed of the drum are both doubled to double-speed reproduce the magnetic tape. In this case, the relative speed is doubled and the reproduction bandwidth is narrow. There was a problem that the signal could not be read stably during search playback.

The present invention has been made in consideration of the above points, and proposes a magnetic recording / reproducing apparatus which can solve the conventional problems all at once and can stably reproduce a signal in both normal reproduction and search reproduction. Is what you are trying to do.

[0013]

In order to solve such a problem, in the present invention, the rotary heads 22A and 22B scan obliquely with respect to the longitudinal direction of the magnetic tape 23 to record and reproduce desired information. In the magnetic recording / reproducing apparatus 1 for reproducing, when the magnetic tape 23 is reproduced at a normal speed, the rotary head 22 of the magnetic tape 23 in the recording track direction is reproduced.
So that the relative speed of A and 22B becomes the first speed R _HN ,
When the rotation of the drum 21 on which the rotary heads 22A and 22B are placed is controlled to search and reproduce the magnetic tape 23 at a speed higher than the normal speed while fast-forwarding or rewinding,
The rotation of the drum 21 is controlled so that the relative speed of the rotary heads 22A and 22B with respect to the magnetic tape 23 becomes the second speed _RHS .

[0014]

The relative speed of the rotary heads 22A and 22B with respect to the recording track direction of the magnetic tape 23 is controlled by the magnetic tape 23.
The signal can be stably reproduced in both the normal reproduction and the search reproduction by changing between the case where the reproduction is performed at the normal speed and the case where the search reproduction is performed.

[0015]

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

(1) Overall Structure of DAT In FIG. 2, reference numeral 20 represents the overall structure of a rotary head type digital audio tape recorder (DAT) as a whole, in which desired audio signals AD _IN and AD _OUT are provided on a drum 21. By using the rotating heads 22A and 22B, recording and / or reproduction can be performed on the magnetic tape 23 wound around the drum 21 at a predetermined angular interval.

In the DAT 20, the input audio signal AD _IN during recording is first input to the audio signal conversion circuit 24. The audio signal conversion circuit 24 has a low-pass filter and an analog digital conversion circuit as a recording processing system, and the inputted audio signal AD _IN
To digital data and input digital data D
It is sent to the recording processing system of the digital signal processing circuit 25 as T _IN .

In the recording processing system of the digital signal processing circuit 25, the input digital data DT _IN is once input RAM data (random access memory) as input audio data DT _AD.
) Is written in the memory circuit 26 having the configuration. The recording processing system of the digital signal processing circuit 25 includes an error correction code generation circuit, an interleave processing circuit, an 8-10 modulation circuit, a parallel-serial conversion circuit, and the like.

As a result, first, the input audio data DT _AD written in the memory circuit 26 is read by the error correction code generation circuit to generate an error correction parity, and then the error correction parity is written in the memory circuit 26. An address corresponding to the data interleave generated in the interleave processing circuit is selected for the writing and reading processes for the memory circuit 26, and the input audio data DT _AD with the error correction parity added in this manner is 8-10. Read by the modulation circuit.

The 8-10 modulation circuit rotates the input audio data DT _AD consisting of 8 bit data to the rotary heads 22A and 22B.
Converts to 10-bit data suitable for magnetic recording by using a sync signal, address signal, subcode signal, ATF
(Automatic track following) Signals are added.

The recording processing system of the digital signal processing circuit 25 converts the recording data thus obtained into a recording signal S _REC0 consisting of serial data in an internal serial / parallel conversion circuit, and the recording processing system of the recording / reproducing amplifier circuit 27. To send to.

A recording processing system of the recording / reproducing amplifier circuit 27 is composed of a recording signal amplifier circuit, a rotary transformer, etc., and an amplified recording signal S _REC1 obtained by amplifying an input recording signal S _REC0 is rotated via a rotary transformer. Drum 21
It is adapted to supply to the upper rotary heads 22A and 22B. Thus, the input audio signal AD _IN can be recorded on the predetermined recording track of the magnetic tape 23.

Here, in this DAT 20, input /
The recording operation or the reproducing operation is selectively controlled based on the operation data D _OPR input from the display circuit 28 to the system control circuit 29 of the microcomputer configuration.

The input / display circuit 28 is composed of, for example, a microcomputer having a key matrix as an operator input means and a display panel having a liquid crystal display element as a display means. As a result, the input / display circuit 28
Is the operation data D in response to the operation of the operator by the user.
_{The OPR} is output and the display on the display panel is performed based on the display data D _DSP input from the system control circuit 29.

Further, the system control circuit 29 controls the mechanical control data D _MC , the signal processing control data D _CNT and the servo processing control based on the system information preset during recording and the operation data D _OPR input from the input / display circuit 28. Data _DSB is generated, and the mechanical control circuit 30,
It is sent to the digital signal processing circuit 25 and the servo processing circuit 31.

Actually, the servo processing circuit 31 at the time of recording receives the servo processing control data D input from the system control circuit 29.
Drum motor 32, capstan motor 3 based on _SB
3, to the reel motor 34, a drum drive signal C _DR , a capstan drive signal C _CP , and a reel drive signal C _{RM, respectively.}
To drive the drum 21 to rotate at a predetermined number of revolutions and to run the magnetic tape 23 at a predetermined speed.

At this time, the drum phase signal PG _DR , the drum frequency signal FG _DR , the capstan frequency signal FG _CP, and the reel frequency signal FG _RM from the drum motor 32, the capstan motor 33, and the reel motor 34 are respectively supplied to the servo processing circuit 31. Are fed back to form a speed servo and / or a phase servo, respectively.

The servo processing circuit 31 is supplied with an internal reference signal D _REF representing one interleave period at the time of recording from the digital signal processing circuit 25. As a result, the servo processing circuit 31 is based on this internal reference signal D _REF. The velocity servo process and / or the phase servo process is executed, and the input drum phase signal PG _DR and drum frequency signal F
The switching reference signal SWP of the rotary heads 22A and 22B generated based on G _DR is sent to the digital signal processing circuit 25.

Further, the mechanical control circuit 30 drives and controls the cassette loading mechanism of the DAT cassette and the tape loading mechanism of the magnetic tape 23 based on the mechanical control data D _MC input from the system control circuit 29. Mechanical information data D _SMC is generated based on the sensor information S _MC input from the mechanical mechanism portion, and this is sent to the system control circuit 29.

[0030] In this case this DAT 20, the interior of the reproducing supplied from the playback time of first servo processing circuit 31 rpm and the digital signal processing circuit 25 in accordance with the servo processing control data D _SB input from the system control circuit 29 The drum motor 32 is rotationally driven in a phase synchronized with the reference signal D _REF to form a speed servo and a phase servo.

In this state, the reproduction signal S _PB0 obtained from the rotary heads 22A, 22B is recorded / reproduced by the rotary transformer, reproduction signal amplification circuit, and waveform equalization circuit 27.
Of the digital signal processing circuit 25. The amplified reproduction signal S _PB2 obtained as a result is supplied to the tracking control circuit 35, and the reproduction digital signal S _PB1 obtained through the built-in binarization circuit is input to the digital signal processing circuit 25. It is supplied to the regeneration processing system.

In the case of this DAT 20, the tracking control circuit 35 is adapted to perform tracking control by the ATF method, for example. That is, the tracking control circuit 35 has an equalizer circuit for detecting a sync signal and an ATF envelope detection circuit, and the ATF is detected from the envelope detection signal based on the timing at which the sync signal is detected in the input reproduction digital signal S _PB1. A signal is detected, an ATF control signal C _ATF is formed according to the ATF signal, and the signal is sent to the servo processing circuit 31.

As a result, the servo processing circuit 31 drives and controls the capstan motor 33 according to the ATF control signal C _{ATF so} that the rotary heads 22A and 22B can accurately trace the recording track of the magnetic tape 23. A
A TF servo loop is formed. When the recording track of the magnetic tape 23 can be accurately reproduced in this way, the reproduction processing system of the digital signal processing circuit 25 starts the reproduction processing for the input reproduction digital signal S _PB1 .

The reproduction processing system of the digital signal processing circuit 25 is composed of a clock reproduction circuit having a PLL (phase locked loop) circuit configuration, a 10-8 demodulation circuit, an error detection / correction circuit, a deinterleave processing circuit, an interpolation circuit and the like. ing.

As a result, the digital signal processing circuit 25
First, the reproduction digital signal S in the clock reproduction circuit
_The playback clock signal included in _PB1 is detected. When the sync signal is detected in the reproduction digital signal S _PB1 in the 10-8 demodulation circuit, 10 bits of the reproduction digital signal S _PB1 are demodulated 10-8 based on the reproduction clock signal detected in the clock reproduction circuit. The obtained 8-bit data is sequentially written in the memory circuit 26 as reproduction audio data DT _AD .

The reproduced audio data DT _AD written in the memory circuit 26 in this manner is read by the error detection / correction circuit to detect the presence / absence of a data error and, if there is a data error, correct the error. Error correction processing is performed by using the data parity and the error-corrected data and the correction result are written in the memory circuit 26.

An address corresponding to the data deinterleave generated in the deinterleave processing circuit is selected for the writing and reading processing for the memory circuit 26, and the reproduced audio data DT _AD after the error detection and correction processing is stored in the interpolation circuit. Read out.

As a result, the interpolating circuit executes an interpolating operation by a method of calculating an average value of the data which cannot be error-corrected with the preceding and following data, and uses this as reproducing digital data DT _OUT to reproduce the audio signal converting circuit 24. Send to the system.

The reproduction processing system of the audio signal conversion circuit 24 has a digital analog conversion circuit and a low-pass filter, converts the reproduction digital data DT _OUT into an analog signal, and sends this as a reproduction audio signal AD _OUT .

Thus, the recording track of the magnetic tape 23 is read by the rotary heads 22A and 22B on the drum 21,
The recorded data recorded on the magnetic tape 23 is reproduced to obtain a reproduced audio signal AD _OUT .

(2) DAT of the embodiment In FIG. 1 in which parts corresponding to those in FIG. 2 are designated by the same reference numerals, 1 indicates a DAT according to the present invention, and the cassette loading mechanism and the tape loading mechanism of DAT 1 are driven. As a result of the operation, the arrow a from the supply reel 3 of the tape cassette 2 loaded inside through the guide shaft 4A
The magnetic tape 23 drawn out as shown by is guided by the inclined guides 5A and 5B and is wound around the drum 21 so as to have a predetermined winding angle.

Thereafter, the magnetic tape 23 is taken up by the take-up reel 6 through the guide shaft 4B of the tape cassette 2,
Thus, in the case of this DAT 1, the magnetic tape 23 is pulled out from the tape cassette 2 and loaded on the drum 21 in a so-called M type.

In the case of this DAT 1, the drum 21 has a rotation frequency detecting device having a frequency generator structure, and the drum frequency signal FG _DR obtained by this is passed through the drum FG amplifier circuit 7 to a servo processing circuit having a microcomputer structure. It is input to the rotation speed detection circuit 9 of the relative speed servo circuit 8 included in 31.

This rotation speed detection circuit 9 measures the drum rotation cycle T _DR based on the input drum frequency signal FG _DR , and the drum rotation speed data DT _DR1 corresponding to this drum rotation cycle T _DR is first subtracted. It is supplied to the circuit 10A as a subtraction input. Further, the reference rotation speed data R _DR input from the reference rotation speed setting circuit 12 is input to the first subtraction circuit 10A as an addition input. The reference rotation speed setting circuit 12 is based on a mode signal NS set and operated from the outside, and the reference rotation speed data R _DRN , R _DRS corresponding to the normal reproduction mode or the search reproduction mode.
To generate the first subtraction circuit 10A
Supply to.

As a result, the first subtraction circuit 10A subtracts the drum rotation speed data DT _DR1 from the reference rotation speed data R _DRN and R _DRS, and the rotation speed error data DT _ERDR obtained as a result of this calculation is _sent to the drum servo processing circuit 13A. Send out. This drum servo processing circuit 13A corrects the input rotation speed error data DT _ERDR by PWM (pulse
width modulation) data is generated and sent to the output circuit 14A as drum drive data DT _DR2 .

As a result, the output circuit 14A converts the drum drive data DT _DR2 into a voltage signal, and the resulting drum drive signal C _DR is fed back to the drum drive motor for driving the drum 21, thus making the drum 21 a mode signal NS. Reference speed data R set based on
_The rotation can be controlled at a rotation speed corresponding to _DRN and R _DRS .

Here, in the case of this embodiment, the reel shafts of the supply reel 3 and the take-up reel 6 each have a rotation frequency detecting device of a frequency generator configuration, and the supply reel frequency signals FG _SP and FG _SP obtained by this are provided. The take-up reel frequency signal FG _TU is input to the relative speed detection circuit 16 of the relative speed servo circuit 8 together with the drum frequency signal FG _DR through the reel FG amplifier circuit 15.

The relative speed detection circuit 16 receives the supply reel frequency signal FG _SP and the take-up reel frequency signal FG.
_The supply reel rotation period T _SP , the take-up reel rotation period T _TU, and the drum rotation period T _DR are measured based on the _TU and the drum frequency signal FG _DR .

Accordingly, the relative speed detecting circuit 16 causes the tape running speed data DT _TP obtained from the sum of squares data T _SP2 + T _TU2 of the supply reel rotation period T _SP and the take-up reel rotation period T _TU , and the drum rotation period T _DR. Using and,

[Equation 2] The relative speed data D _TH of the actual magnetic tape 23 and the drum 21 is detected by executing the arithmetic processing represented by, and this is subtracted and input to the second subtraction circuit 10B.

Further, the mode signal N from the reference relative speed setting circuit 17 is used as an addition input to the second subtraction circuit 10B.
Reference relative speed data R _HN , R _HS set based on S
Is input, whereby the second subtraction circuit 10B subtracts the relative speed data D _TH from the reference relative speed data R _HN and R _HS, and the relative speed error data DT _ERH that is the calculation result.
Is sent to the reel servo processing circuit 13B.

This reel servo processing circuit 13B is a PWM for correcting the input relative speed error data DT _ERH.
Data is generated, and this is sent to the output circuit 14B as the take-up reel drive data DT _TU .

As a result, the output circuit 14B converts the take-up reel drive data DT _TU into a voltage signal, and the take-up reel drive signal C _TU obtained as a result is fed back to the take-up reel drive motor for driving the take-up reel 6. Thus, the magnetic tape 23 can be held at the traveling speed corresponding to the reference relative speed data R _HN and R _HS set based on the mode signal NS.

As described above, in the case of the relative speed servo circuit 8 according to this embodiment, the rotation of the drum 21 and the running of the magnetic tape 23 are controlled based on the mode signal NS. The relative speed in the track direction between the rotary head 23 and the rotary heads 22A and 22B can be controlled to a speed based on whether the normal reproduction or the search reproduction is performed.

As a result, for example, with respect to the DAT 1 having the diameter of the drum 21 of 18 [mmφ] described above, the reference rotation speed setting circuit 12 and the reference relative speed setting circuit 17 are used.
, The relative speed during normal playback is 20% of 1.57 [m / S]
Increase the first speed to 1.88 [m / S],
On the other hand, if the relative speed during search reproduction is set to the second speed of 1.57 [m / S], the reproduced data can be correctly obtained in any case.

When the magnetic tape 23 is reproduced at a double speed, the drum rotation speed is 4000 [rpm] and the clock rate is doubled as usual. It was rotated at [rpm] to reach the first relative speed, and the drum 21 was rotated at 2000 [rpm] at the time of double speed search reproduction so as to reach the second relative speed. In either case, the reproduced data can be obtained correctly.

According to the above construction, the rotary head 22A,
The rotation head 22 of the magnetic tape 23 with respect to the recording track direction is controlled by controlling the rotation of the drum 21 on which 22B is placed.
By setting the relative speed of A and 22B to the first speed when reproducing the magnetic tape 23 at the normal speed and to the second speed when reproducing the magnetic tape 23, it is possible to perform either normal reproduction or search reproduction. In the case of, DAT1 capable of stably reproducing the signal can be realized.

(3) Other Embodiments (3-1) In the above embodiment, the case where the running speed of the magnetic tape is detected from the cycle information of the supply reel and the take-up reel has been described. Alternatively, the invention may detect the running speed of the magnetic tape from the rotation cycle of the capstan when the DAT performs the recording and / or reproducing operation. By doing so, since the running speed of the magnetic tape can be detected with higher accuracy, the relative speeds of the magnetic tape and the rotating head can be kept constant with even higher accuracy.

(3-2) In the above embodiments, the case where the present invention is applied to a digital tape recorder has been described, but the present invention is not limited to this, and various magnetic fields such as a video tape recorder and a data recorder can be used. It is suitable for wide application to recording and reproducing devices.

[0059]

As described above, according to the present invention, the relative speed of the rotary head with respect to the recording track direction of the magnetic tape is changed between when the magnetic tape is reproduced at the normal speed and when it is searched and reproduced. By doing so, it is possible to realize a magnetic recording / reproducing apparatus capable of stably reproducing a signal in both normal reproduction and search reproduction.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a digital audio tape recorder according to the present invention.

FIG. 2 is a block diagram showing the overall configuration of a digital audio tape recorder.

[Explanation of symbols]

1, 20 ... DAT, 2 ... Tape cassette, 3 ... Supply reel, 6 ... Take-up reel, 7 ... Drum FG amplifier circuit, 8 ... Relative speed servo circuit, 9 ... Rotation speed detection circuit, 10A, 10B ... Subtraction circuit, 12 ... Reference rotation speed setting circuit, 13A ... Drum servo processing circuit, 13B
... reel servo processing circuit, 14A, 14B ... output circuit, 15 ... reel FG amplifier circuit, 16 ... relative speed detection circuit, 17 ... reference relative speed setting circuit.

Claims (1)

[Claims] 1. A magnetic recording / reproducing apparatus for recording and reproducing desired information by scanning a rotary head obliquely with respect to a longitudinal direction of the magnetic tape, wherein the magnetic tape is reproduced at a normal speed. The rotation of the drum on which the rotary head is mounted is controlled so that the relative speed of the rotary head with respect to the recording track direction of the magnetic tape becomes a first speed, and the speed of the magnetic tape is faster than the normal speed. Then, when the search reproduction is performed while fast-forwarding or rewinding, the rotation of the drum is controlled so that the relative speed of the rotary head with respect to the magnetic tape becomes the second speed. Recording / playback device.