JPH01151045A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain the interchangeability of a magnetic recording and reproducing device without receiving the influence such as a secular change by constituting digitally a device and obtaining a delaying processing signal at the timing which is a target obtained based on the delaying data equal to the correcting data. CONSTITUTION:The rotation phase of magnetic heads 3a and 3b is controlled with a delaying signal obtained by delaying a detecting pulse obtained from the detecting signal of a rotation detector 10 based on initial data, and the detecting data are automatically obtained based on the date difference in reference data concerning the latch data equivalent to the phase difference between the signal detected from a reproducing video signal obtained by demodulating a reproducing FM signal obtained at this time and the delaying signal in an initial condition and the already known latch data beforehand when the delaying signal is assumed to be at the timing which is a target. Based on the delaying data equal to the correcting data obtained by adding the detecting data and the initial data, a delaying signal at the timing which is the target obtained by delaying digitally the phase of the rise and fall of the detecting pulse is used. Thus, the interchangeability of the magnetic recording and reproducing device is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording/reproducing device, and particularly to an improvement in phase adjustment in a phase control system thereof.

[Conventional technology]

For example, a VTR that records and plays back information signals such as video signals.
In a rotary head type magnetic recording/reproducing device such as the above, the phase relationship between the information signal recorded at a predetermined position on a recording medium such as a magnetic tape, or the information signal reproduced from the recording medium and the rotary head is kept constant. In addition, the phase of the rotary head is controlled. A specific example is shown in FIG.

In FIG. 3, 1 is a rotating drum, 7 is a driving motor, and the driving motor 7 rotates the rotating drum 1 in the direction of arrow 2 at a constant speed.

3a and 3b are two magnetic heads that rotate integrally with the rotary drum 1, and these are provided facing each other with a distance of 180''.
α) are in contact with each other during the period. Reference numeral 4 indicates a rotating body that rotates integrally with the rotating drum 1, and 5a and 5b indicate N-pole and S-pole magnets, respectively, which are installed facing the rotating body 4 at a distance of 180'. The pair 3a and 3b are attached with a predetermined angular difference.

Reference numeral 6 denotes a fixed position sensor consisting of a detection coil or a magnetically sensitive element such as a Hall element.
It constitutes 0. The position sensor 6 is a pair of magnets 5a rotating in opposition to each other.

Detection signal S1 corresponding to the polarity of the magnet every time it faces 5b
Output. That is, the detection signal output from the position sensor 6 equivalently detects the positions of the magnetic healds 3a and 3b.

However, the rotation side magnet pair 5 constituting the rotation detector 10
Since there are variations in the mounting positions of a, 5b and the position sensor 6 on the fixed side,
Variations also occur in the relative position with respect to the 0 detection signal. Furthermore, there are variations in absolute position in the mounting positions of the rotary heads 3a and 3b.

Therefore, as a countermeasure against this variation, a predetermined signal in the information signal, for example, a vertical synchronization signal of a video signal, is recorded at a predetermined position on a recording track on a reference tape, that is, a recording medium, in a recording track pattern that can satisfy compatibility between VTRs. The tape on which is formed is played back, and the rad 3a is
It is also necessary to correct variations in the relative position between the reference tape 3b and the rotation detector 10, so as to maintain a constant phase relationship between the information signal reproduced from the reference tape and the rotary head.

In this way, the rotating healds 3a and 3b and the rotation detector 10
In order to correct the variation in relative position that exists between
The signal amplified in step 1 is input to a pulse generator 12 consisting of a Schmitt circuit or the like to obtain a detection pulse P1, which is input to a monostable multi-circuit 13. Monostable multi circuit 13
For example, the phase of the input detection pulse P1 is adjusted by varying the resistance value of the volume VRI, and the obtained signal H3 is outputted and inputted to one input terminal of the comparison input signal comparison phase shifter 14. The other input terminal of the phase comparator 14 receives a phase reference signal REF created from a vertical synchronization signal in a video signal recorded by a VTR, for example, and outputs a phase error signal Pe regarding the two-person power signal H3 and REF. .

This phase error signal Pe is amplified by the deviation amplifier 15, and the amplified signal is used as a command signal to the drive circuit 16 of the drive motor 7 that rotates the rotary drum 1, thereby rotating the rotary magnetic heads 3a and 3b. Phase is controlled.

If the above-mentioned measures are taken, the phase relationship between the information signal recorded at a predetermined position on the recording medium and the rotating head will also be almost constant even when recording is subsequently performed, and compatibility between VTRs will be satisfied. The recorded trunk pattern can be obtained.

[Problem that the invention seeks to solve]

In the phase control of the rotary head of a conventional magnetic recording/reproducing device, as described above, while observing the reproduction information signal from the reference tape, the RC which is a component of the monostable multi-circuit 13 is
This requires the complicated work of adjusting the phase of the rotary head by adjusting the time constant for each device one by one. In addition, because there is a temporal drift in the monostable multi-circuit 13 due to aging and temperature characteristics of RC components, the characteristics of the phase control system change, and the rotating head is accurately positioned at a predetermined position on the magnetic tape. There have been problems such as the drift of delay circuits such as monostable multi-circuits cannot be ignored when even more precise control performance is desired. This was done to solve the problem, and the aim is to obtain a magnetic recording/reproducing device that can adjust the phase of the head without being affected by drift, based on automatically derived delay data for phase adjustment. purpose.

[Means for solving problems]

The magnetic recording/reproducing device according to the present invention uses a detection pulse obtained from a detection signal of a rotation detector as an initial state when reproducing a reference tape to a magnetic head using a delay signal obtained by delaying the detection pulse based on initial data. A latch corresponding to the phase difference between the vertical synchronization signal detected from the reproduced video signal after demodulating the reproduced FM signal obtained when the magnetic head is in contact with the reference tape and the delayed signal in the above-mentioned initial state. Detection data is automatically obtained based on the data difference between the data and the target value in the previously known latch data, assuming that the delayed signal is at the target timing, and the detection data and the initial data are combined. The rising and falling phases of the detection pulse are digitally delayed based on delay data equal to the correction data obtained by addition, thereby obtaining a delayed signal at the target timing.

[Effect]

In this invention, the device is configured digitally as described above, and the delayed processed signal at the target timing obtained based on the delay data equal to the correction data is obtained. Don't accept it (,
Rotational phase control of the magnetic head is performed that satisfies compatibility with magnetic recording and reproducing devices.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram showing the configuration of a magnetic recording and reproducing apparatus according to an embodiment of the present invention. In FIG. 1, parts marked with the same symbols as the conventional example shown in FIG. belongs to.

That is, 1 is a rotating drum, and 3a and 3b are magnetic helads provided on the rotating drum 1 at a distance of 180 degrees and facing each other.
+α) It rotates integrally with the rotating drum 1 while facing each other for a period of time. Reference numeral 10 denotes a rotation detector, and its configuration in this embodiment is the same as in the conventional example shown in FIG. It is assumed that the sensor is composed of a sensor 6.

Note that the configuration of the rotation detector 10 is not limited to that shown in FIG. 3, and various configurations can be adopted.

Further, 11 is an amplifier that amplifies the detection signal si of the rotation detector 10, 12 is a pulse generator that outputs the detection pulse P1, and 100 is a phase that outputs a signal obtained by delaying the rising and falling phases of the detection pulse P1, respectively. shift circuit, 14
15 is a phase comparator whose phase comparison inputs are the output of the phase shift circuit 100 and the reference signal REF, and 15 is a phase error signal Pe.
16 is a drive circuit that drives the motor 7.

Further, 51 and 52 are reproduction FM signals of the rotary heads 3a and 3b.
53 is a switching circuit for the outputs of both amplifiers 51 and 52; 54 is an FM demodulator;
A vertical synchronization detector 5 detects and separates a vertical synchronization signal (hereinafter referred to as VS) from the reproduced video signal. Also, 20
0 is a correction detection unit, 35 and 36 are first and second memories,
31 and 32 are first and second setting devices; 33 and 34 are switches for switching between the first memory 35 or the output of the first setting device 31 and the output of the second memory 36 or the second setting device 32; It is.

Next, the operation will be explained. In the magnetic recording and reproducing apparatus configured as described above, as explained in the conventional example in FIG. Therefore, it is necessary to correct the variation in relative position so that the phase relationship between the reproduction information signal obtained when the reference tape is reproduced and the rotary head becomes a predetermined relationship.

Therefore, in FIG. 1, the reference tape is reproduced to correct variations in the relative positions of the rotating magnetic disks 3a and 3b and the rotation detector 10.

That is, the detection signal S1 from the rotation detector 10 is sent to the amplifier 11.
The amplified signal is input to a pulse generator 12 consisting of a Schmitt trigger circuit or the like to obtain a waveform-shaped detection pulse P1, which is then sent to a phase shift circuit 100 along with a clock CK.
Enter.

FIG. 2 is a time chart diagram explaining the operation of FIG. 1, in which FIG. 2(a) shows the detection pulse P1, and FIG. 2(b) shows the clock CK.

In the phase shift circuit 100, 21 is a data selector, 22 is a reset circuit, 23 is a counter, 24 is a latch circuit, and the reset circuit 22 receives an input clock C.
Using K and the detection pulse PL, for example, a preset pulse PR of one clock width is synchronized with the rise of the clock CK for each of the rise and fall of the detection pulse P1.
is output as shown in FIG. 2(C).

The first delay data (DP) and the second delay data (DH) are input to the data selector 21, but in the initial state where the reference tape is played back as described above, the first and second delay data (DP) and (DH), the first initial data (Dl) indicated by the first setting device 31 and the second setting device 32
The switches 33 and 34 are switched so that the second initial data (D2) indicated by is given. That is, the variation in the relative position between the rotation detector 10 and the rotating magnetic heads 3a and 3b in the magnetic recording/reproducing apparatus is not infinitely large, but falls within a certain range based on the mounting error of each. Therefore, the first initial data (
The values of Dl) and second initial data (D2) are set in advance so that no missing period occurs in the amplified reproduced FM signal from the amplifier 53 selected by the delayed signal (H3W) output from the phase shift circuit 100. It can be set.

In this way, the first delay data (DP
) and the second delay data (Dll) are inputted, the data selector 21 receives the detection pulse (Dll) inputted at the same time.
Count data (C) is selectively controlled by, for example, high-level and low-level signals of Pl), and first delay data (DP) and second delay data (DH) appear alternately.
D) is output.

The counter 23 receives a preset pulse (PR), count data (CD) and a clock (CK), and every time it is set by the preset pulse (PR) in FIG. 2 delayed data (
DN), that is, by alternately performing counting based on the first initial data (DI) and the second initial data (D2), a count output (C1) is obtained as shown in FIG. 2(d). Then, in the launch circuit 24, the count output (C1)
By using the detection pulse (Pl) as a clock input and the detection pulse (Pl) as a data input, the rising and falling edges of the detection pulse (Pl) correspond to the first delay data (D, ) and the second delay data (DH), respectively. The delayed signal (H3W) is output from the phase shift circuit 100 as shown in FIG. 2(e). Then, such a delayed signal (H3
W) is used as a so-called head switching signal by the phase comparator 14;
The signal is input to the switch 53 and the correction detection section 200.

First, the phase reference signal (REF) inputted together with the delayed signal (H3W) to the phase comparator 14 is detected by the phase comparator 14 as an error signal (Pe) related to the phase difference, and the error signal (P e ) is amplified by the deviation amplifier 15 and then input as a command signal to the drive circuit 16 of the drive motor 7 for driving the rotating drum 1, thereby controlling the rotational phase of the magnetic helads 3a and 3b. be done.

The magnetic heads 3a and 3b whose rotational phases are controlled in this way
The reproduced FM signals obtained by constant rotation while being in contact with the reference tape for a period of (180'+α) are amplified by the first reproduction amplifier 51 and the second reproduction amplifier 52, respectively, and then manually inputted to the switching circuit 53. .

The delay signal (H3W) output from the phase shift circuit 100 is input to the switching circuit 53 as a switching control signal.
The first reproducing amplifier 51 or the second reproducing amplifier 5 depending on the noise level or low level of the delayed signal (H3W).
The two amplified outputs are selectively switched alternately, and a switching signal (K
O) is output. As described above, the first initial data (Dl) and second initial data (B2) that determine the phase in the initial state of the delayed signal (H3W), which is the switching control signal of the switch 53, are the switching control signal of the switch 53. The output switching signal (KO>) is set to a value such that no missing period occurs in the output switching signal (KO>).

Then, the switching signal (KO) output from the switching circuit 53
is input to the FM demodulator 54, and a reproduced video signal (K1) in an initial state as shown in FIG. 2(f) is obtained. The reproduced video signal (K1) is simultaneously transmitted to the vertical synchronization signal detector 55.
is input to 1 field of the reproduced video signal (Kl).
For example, the V-SYNC detection signal as shown in FIG. (vl).This V-5
The YNC detection signal (vl) is input to the latch pulse circuit 56, which outputs a latch pulse (B1) synchronized with, for example, the rising edge of the V-3 YNC detection signal (1) as shown in FIG. 2(h).

Further, the delayed signal (H3W) in the initial state from the phase shift circuit 100 is input to the preset circuit 74 in the correction detection section 200, and is synchronized with the rising and falling edges of the delayed signal (H3W), and is synchronized with, for example, a clock (CK). The first preset pulse (A1) has a pulse width of one clock of
and a second preset pulse (A2) as shown in FIG. 2 (1) and U), respectively. and clock (CK)
At the same time, the count of the first counter 75 is reset by the first precent pulse (A1) inputted to the first counter 75, and starts counting the number of pulses of the clock (GK). Also, a second preset pulse (A2) is inputted to the second counter 76 along with the clock (CK).
This resets the count of the second counter 76 and starts counting the number of clock (CK) pulses.

The count data of the first counter 75 is the first latch circuit 7
7, but has the same phase as the first preset pulse (A1) in FIG. 2(1) in the latch pulse (B1) shown in FIG.
BIO), the count data is latched, and the first latch circuit 77 outputs first rough data NP.

Note that at the time when the first initial data (Dl) and second initial data (B2) in the initial state are set, the first preset pulse (A1) and latch pulse (B2) in the initial state are set.
The phase relationship with 1) can be roughly predicted. That is, the phase difference between the pulse (BIO) in the latch pulse (Bl) shown in FIG. 2 (h) that appears first after the first preset pulse (A1) and the first preset pulse (A1) is within a certain range. Therefore, the first preset pulse (A1
), i.e., the latch pulse (Bl) is in phase more than one field away from the first preset pulse (Al) in FIG. 2 (hl). Pulse in pulse (B1) (
Bll) should not accept latch operations.

The first latch data (Np) from the first latch circuit 77 obtained as described above is generated from the rising edge of the delay signal (H3W) in the initial state shown in FIG. This data corresponds to the phase difference up to the rising edge of the V-3YNC detection signal (vl) of one field of the reproduced video signal in the initial state shown in g).

Similarly, the second launch circuit 78 receives the count data and the latch pulse (B1) output from the second counter 76, which has been counting after being reset by the second preset pulse (A2). Latch pulse (
The second latch data (NN
) is output. That is, the second roughh data (NN)
is the delayed signal (H3
This data corresponds to the phase difference from the falling edge of V-3YNC detection signal (vl) of the other field of the reproduced video signal in the initial state shown in FIG. 2 (gl).

The above first rough data (N,) and second rough data (NN) are stored in, for example, a continuous memory (ROM).
) is input as a subsequent address to a first detector 79 and a second detector 80. That is, the phase shift circuit 100
Since the target phase of the delayed signal (H3W) outputted by is known in advance, the target data of the first luff data (NP) and the second latch data (NN) described above are also the same as the first reference data (P, -r) and the second reference data (N1.f). Therefore, in the first detector 79 and the second detector 80, the first latch data (Np) and the first reference data (p
By storing in advance the data difference between the second latch data (NN) and the second reference data (Nr-r) in the initial state, the first latch data (N , ) and second roughh data (
N8), first detection data (Ml) and second detection data (M2) are output. These first and second detection data (Ml) and (M2) are respectively delayed signals (
The initial state phase with respect to the target phase of H3W) is
This shows how far the rising and falling edges deviate.

Therefore, the first detection data (Ml) and the first initial data (D
I) in the first adder 85, the first correction data (N1) is output, and the second detection data (M2)
and the second initial data (B2) in the second adder 86, thereby outputting the second correction data (N2).

These first correction data (N1) and second correction data (N
2) are respectively input to the phase shift circuit 100, the phase shift circuit 100 will output a delayed signal (H3W) of the target phase. Therefore, the first correction data (N1) and the second correction data (N2) are input into the first memory 35 and the second memory 36, which are programmable ROMs, respectively, and the first correction data (Ml) and the second correction data (N2) are inputted to the respective predetermined addresses. The second correction data (M2) is written.

After this, if the corresponding addresses of the first memory 35 and the second memory 36 are always used in the read state, even when the power of the device is turned off and then turned on again, by reading the respective addresses, the first memo I735 The first target data (Xl) which is equal to the first correction data (N1) is output from the second memory 36, and the second target data (N2) which is equal to the second correction data (N2) is output from the second memory 36.

Such first target data (Xl) and second target data (N
2) becomes the first delayed data (D, ) and the second delayed data (DM), the phase shift circuit (100) outputs a delayed signal of the target phase. (H3W) can be obtained.

As a result of the above, even when recording is performed thereafter, the phase relationship between the information signal recorded at a predetermined position on the recording medium and the rotating magnetic head is also approximately constant, and the recording track satisfies compatibility between VTRs. You can get the pattern.

〔Effect of the invention〕

As described above, according to the magnetic recording and reproducing apparatus according to the present invention, the delay obtained by delaying the detection pulse obtained from the detection signal of the rotation detector based on the initial data as the initial state when reproducing the reference tape The rotational phase of the magnetic head is controlled using the signal, and at this time, the magnetic head is in contact with the reference tape to demodulate the reproduced FM signal obtained and is detected from the reproduced video signal obtained. Detected data is automatically determined based on latch data corresponding to the phase difference with the delayed signal of , to the target timing obtained by digitally delaying the rising and falling phases of the detection pulse, respectively, based on delay data equal to correction data obtained by adding the detection data and the initial data. By using a certain delay signal, we can control the rotational phase of the magnetic head that satisfies the compatibility of the magnetic recording and reproducing device, so the phase of the rotating magnetic head can be automatically adjusted, and the monostable multi-circuit It is hardly affected by the drift that exists in delay circuits such as the above, and stable and highly accurate phase control can be realized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an automatic phase adjustment device for a magnetic recording/reproducing device according to an embodiment of the present invention, FIG. 2 is a time chart for explaining the operation of FIG. 1, and FIG. 3 is a conventional FIG. 2 is a block diagram showing a phase adjustment device. In the figure, 12 is a pulse generator, 100 is a phase shift circuit, 200 is a correction detection section (correction detection means), 35 and 36 are memories (storage means), 14 is a phase comparator (phase comparison means), and 10 is a rotation Detector (rotation detection means), 3a and 3b are magnetic heads, 85 and 86 are adders (calculation means), 31 and 32 are setting devices, 33 and 34 are switches,
55 is a vertical synchronization detector, and 56 is a latch pulse circuit. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) Rotation detection means that outputs a detection signal regarding the position of the rotating magnetic head; a detection pulse generator that generates a detection pulse from the detection signal; and a delayed signal that delays the rising and falling phases of the detection pulse, respectively. a phase shift circuit that outputs a phase shift circuit; a phase comparison unit that inputs the delayed signal outputted by the phase shift circuit as a comparison input signal together with a phase reference signal and detects a phase error signal related to both signals; compatibility between an FM demodulator that outputs a reproduced video signal from a reproduced FM signal, a vertical synchronization detector that outputs a vertical synchronization signal detection signal from the reproduced video signal output by the FM demodulator, and a magnetic recording and reproducing device. the delay signal whose delay amount is determined based on the initial data output from the phase shift circuit in an initial state when playing back a reference tape recorded in a predetermined format that can be met; and the vertical synchronization signal in the initial state. Data corresponding to the phase difference with the detection signal,
and the delayed signal and the target in the initial state based on previously known reference data corresponding to the phase difference between the delayed signal and the vertical synchronization signal detection signal in the initial state, assuming that the phase is at the target timing. correction detection means for outputting detection data indicating a phase difference between the rotation head and the rotation detection means; and a calculation means for calculating correction data indicating a phase difference between the rotation head and the rotation detection means from the initial data and the detection data. , storage means for storing the correction data obtained by the calculation means and outputting it as target data; and storage means for storing the initial data in an initial state when the reference tape is played back, and for storing the correction data after the point in time when the target data is output. A switch for outputting target data as delay data for determining the amount of delay to each of the phase shift circuits, and a drive circuit for a motor that is controlled by the phase error signal and drives the rotating magnetic head. A magnetic recording and reproducing device.