JPH07192355A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To perform tracking control over four heads by using a fourfrequency ATF pilot signal. CONSTITUTION:At recording time, an ATF pilot signal f1 generated by an ATF pilot signal generator 20-1 is supplied to a head A1 through an adder 33, a switch SW 2, and a rotary transformer 5-2, an ATF pilot signal f3 to a head B1 through a similar path, an ATF pilot signal f2 generated by a signal generator 20-2 to a head A2 through a similar path, and an ATF pilot signal f4 to a head B2 through a similar path. Consequently, these signals f1, f2, f3, and f4 are recorded cyclically on the tape in order. At reproduction time, reproducing signals of the heads A1 and B1 are inputted to a tracking error detecting circuit 15 to generate an ATF error signal from a crosstalk component reproduced from an adjacent track, and this is fed back to a tracking control circuit 13 and a motor driving amplifier 10 which drives a capstan motor 8, thereby performing the tracking control over the four heads.

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 apparatus which superimposes a tracking signal on a video signal by a head on a rotary cylinder and records it on a tape by a helical scan method, and then reproduces it. Tracking control in case of configuration.

[0002]

2. Description of the Related Art As is well known, a method of superimposing a tracking signal on a tape together with a video signal by a video head on a rotary cylinder and performing tracking control by the tracking signal at the time of reproduction is a 8 mm VTR standard. The 4-frequency ATF method has been put to practical use. The operation will be described below.

FIG. 4 shows the above-mentioned 8 mm VTR standard.
It is a block diagram which showed the prior art example of the magnetic recording / reproducing apparatus which employ | adopted the frequency ATF system. The magnetic tape 7 is helically wound around the rotary cylinder 3 which rotates in the direction of arrow a in the figure by the inclined posts 1 and 2, and the heads A and B on the rotary cylinder 3 cause the tape 7 to travel in the direction of arrow b in the figure. In the helical scan method, the ATF pilot signal (tracking signal) and the video signal are superposed and recorded.

During recording, ATF pilot signal generator 2
0 synchronizes the ATF pilot signals f1, f2, f3, f4 based on the clock 19 with the switching pulse 18 generated from the switching pulse generation circuit 17 as shown in FIG. ) It occurs cyclically as shown in. Switching pulse generation circuit 17
Is the rotary cylinder 3 output from the pulse generator 4.
The switching pulse 18 shown in FIG. 6B is generated in synchronization with the PG pulse signal shown in FIG. The ATF pilot signal output from the ATF pilot signal generator 20 is added to the adder 2
6 and 27 mix (superimpose) with the recording video signal,
This mixed signal is passed through the switches SW1 and SW2 (switched to the terminal a side at the time of recording) and the rotary transformer 5 by the trace heads A and B selected as shown in FIG. 7 is recorded as shown in FIG. As a result, the AT recorded on the tape 7
The F pilot signal changes cyclically in the order of f1 → f2 → f3 → f4 every half cycle of the switching pulse 18.

During reproduction, the switches SW1 and SW2 are switched to the terminal b side, and the reproduction signals of the heads A and B are sent to the video reproduction circuit 24 and the tracking error detection circuit 15. When the reproduction signal is input to the tracking error detection circuit 15, the reproduction signals of the heads A and B are alternately selected by the switch SW3 and input as the reproduction RF signal 16 every time the switching pulse 18 is switched.

FIG. 5 shows the tracking error detection circuit 1
5 is a block diagram showing details of FIG. The reproduction RF signal 16 is input to the low pass filter (LPF) 51, where
The ATF pilot signal is separated from the video signal.
The separated ATF pilot signal is input to the multiplier 52, where it is multiplied by the reference pilot signal (the same frequency as the pilot signal of the track currently being reproduced) 60. As a result, the crosstalk pilot signal component and the beat component (47K
Hz, 16 KHz) is generated. These beat components are extracted by the bandpass filters (BPF) 53 and 54 and input to the subtractor 55. The subtracter 55 subtracts the beat component of 16 KHz from the beat component of 47 KHz, amplifies the obtained difference by the amplifier (AMP) 55, and outputs it as a tracking error (ATF error) signal 19.

As shown in FIG. 7, when the head A is tracing the center of the f1 track, the crosstalk (f4, f2) of the pilot signals from the adjacent tracks is at the same level, and f1 (refund pilot) and f4 are the same. Beat component of 47 KHz and beat component 16 of f1 and f2
KHz also becomes the same level, and the ATF error signal after subtraction by the subtractor 55 becomes zero. However, when the head locus deviates to the f2 side, the 16 KHz component becomes large, and f4
If the locus of the head deviates to the side, the 47 KHz component becomes large. Thus, the ATF error signal 14 which is the output of the tracking error detection circuit 15 is a signal which changes according to the running phase of the tape. The ATF error signal 14 is subjected to gain adjustment and phase compensation by the tracking control circuit 13 and then added to the control signal output from the capstan rotation speed control circuit 11, and this addition signal is input to the motor drive amplifier 10. To be done. The motor drive amplifier 10 controls the rotation phase of the capstan motor 8 according to the input signal so that the ATF error signal becomes zero. The rotational force of the capstan motor 8 is transmitted to the tape 7 by the pinch roller 6 and runs the tape 7 in the direction of arrow B in the figure. At this time, the running phase of the tape 7 is controlled by the tracking control circuit 13. The rotation speed control circuit 11 is a capstan motor 8 obtained from the speed detector 9.
A control signal for controlling the rotation speed of the capstan motor 8 is created from the speed signal corresponding to the rotation speed of, and this is output to the adder 12.

However, the tracking control by the conventional four-frequency ATF method described above is put to practical use in a video tape recorder (VTR) which records and reproduces a video signal by the two heads A and B on the rotary cylinder 3, but will be put to practical use in the future. There is a problem that it is difficult to apply it to a VTR by simultaneous recording / reproducing of two channels by four heads which will be realized.

[0009]

Conventionally, a 4-frequency AT is used.
It has been put into practical use that the tracking signal is superposed on the video signal and recorded on the tape by the F method, and the tracking control of the reproducing head is performed by reproducing the tracking signal during reproduction. However, conventional 4-frequency AT
Since the F system has been put to practical use in a magnetic recording / reproducing apparatus that performs recording / reproducing with two heads, it will be applied as it is to a magnetic recording / reproducing apparatus that will carry out two-channel simultaneous recording / reproducing with four heads that will be put into practical use in the future. There was a problem that it was difficult.

Therefore, the present invention has been made in view of the above problems, and magnetic recording capable of highly accurately performing tracking control of four heads on a rotary cylinder for simultaneously recording / reproducing two channels by a four-frequency ATF method. It is intended to provide a reproducing device.

[0011]

According to the present invention, the heads A1 and A2 are arranged 180 degrees opposite to each other on the outer peripheral portion of the rotary cylinder, and the heads B1 and B2 are arranged 180 degrees opposite to each other, and the head A1 and A2 are arranged opposite each other. A magnetic recording / reproducing apparatus for recording / reproducing 2-channel video signals on the tape simultaneously by these 4 heads is provided in the vicinity of A2 and between the heads B1 and B2 by providing an angle step difference of Δθ, and these four heads are used to record four-frequency signals. Pilot signal generating means for generating pilot signals f1, f2, f3, f4, pilot signal f1 generated by this pilot signal generating means for the head A1, pilot signal f2 for the head A2,
The pilot signal f3 is obtained from the head B1 and the pilot signal f4 is supplied to the head B2 by superimposing the video signal on the head B2, and at the time of reproduction, from any one or any two of the four heads. Selection means for selecting a reproduction signal and control for responding to the imbalance of these crosstalk components by extracting the crosstalk components of the pilot signals reproduced on the left and right adjacent tracks from the reproduction signal obtained by the selection means. It has a configuration including an error detecting means for detecting a signal and a control means for controlling the running phase of the tape based on the error signal detected by the error detecting means.

[0012]

In the magnetic recording / reproducing apparatus of the present invention, the pilot signal generating means at the time of recording has the 4-frequency pilot signal f.
1, f2, f3, f4 are generated. The pilot signal supply means outputs the pilot signal f1 generated by the pilot signal generation means to the head A1, the pilot signal f2 to the head A2, the pilot signal f3 to the head B1, and the pilot signal f4 to the head B2. The signal is superimposed and supplied. At the time of reproduction, the selection means selects a reproduction signal obtained from any one or any two of the four heads. The error detecting means detects the control signal corresponding to the imbalance of these crosstalk components by extracting the crosstalk components of the pilot signals reproduced on the left and right adjacent tracks from the reproduction signal obtained by the selecting means. The control means controls the running phase of the tape based on the error signal detected by the error detecting means. As a result, the tracking pilot signal can be recorded on the tape in the order of f1, f2, f3, f4, and at the time of reproduction, the tape phase ( (Tracking) can be controlled to perform tracking control of four heads.

[0013]

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 showing an embodiment of a magnetic recording / reproducing apparatus of the present invention. At the time of recording, the ATF pilot signal generator 20-1 is
The F pilot signals f1 and f3 are cyclically generated as shown in FIG. 2C in synchronization with the switching pulse 18 as shown in FIG. 2B generated from the switching pulse generation circuit 17. The ATF pilot signal generator 20-2 outputs the ATF pilot signals f2 and f4 based on the clock 19 to the switching pulse generation circuit 1
2 is cyclically generated as shown in FIG. 2D in synchronization with the switching pulse 18 shown in FIG. The switching pulse generation circuit 17
Is the rotary cylinder 3 output from the pulse generator 4.
The switching pulse 18 is generated in synchronization with the pulse signal as shown in FIG.

The ATF pilot signal f1 or f3 output from the ATF pilot signal generator 20-1 is output to the adders 31 and 33, and the ATF pilot signal f2 output from the ATF pilot signal generator 20-2. f
2 or f4 is output to the adders 32 and 34. here,
22 is a video signal generation source for generating a recording video signal,
The 2-channel video signals 101 and 102 are output from the video signal generation source 22 to the adders 31 and 33. The video signal 101 generated from the video signal source 22;
The delay circuit 102 is delayed by the delay circuit 23 for a predetermined time to become delay signals 201 and 202, which are input to the adders 34 and 32. The delay time of the delay circuit 23 is the rotation cylinder 3
It is determined in correspondence with the angle division Δθ between the heads A1 and A2 or the angle division Δθ between the heads B1 and B2 mounted above.

The adder 31 uses the ATF pilot signal f1.
Alternatively, f3 is mixed with the video signal 101, and the mixed signal is output to the terminal a side of the switch SW4. The adder 32 mixes the ATF pilot signal f2 or f4 with the video signal 202, and switches the mixed signal to the switch S.
Output to the terminal a side of W3. The adder 33 mixes the ATF pilot signal f1 or f3 and the video signal 102, and outputs the mixed signal to the terminal a side of the switch SW2. The adder 34 mixes the ATF pilot signal f2 or f4 with the video signal 201, and outputs the mixed signal to the terminal a side of the switch SW1.

The mixed signals input to the terminals a of the switches SW1, 2, 3, 4 are supplied to the rotary transformer 5-.
It is supplied to the heads A2, A1, B2, B1 on the rotary cylinder 3 via 1, 5-2, 5-3, 5-4. As a result, the ATF pilot signals f1 to f4 are recorded on the tape 7 in a trace pattern as shown in FIG. 3 by the heads A1, A2 and B1, B2, and as shown in FIG.
The TF pilot signals f1, f2, f3, f4 will be recorded on the tape 7 sequentially and cyclically.
The heads A1 and B1 and the heads A2 and B2 are arranged on the rotary cylinder 3 so as to face each other by 180 °, and the heads A1 and A2 and the heads B1 and B2 are provided with a step of Δθ by an angle division. The track pattern is as shown in FIG.

At the time of reproduction, the switches SW1 and SW2 are switched to the side of the terminal b, the reproduction signals of the heads A1, A2, B1 and B2 are sent to the video reproduction circuit 24, and the reproduction signals of the heads A1 and B1 are also tracking error detection circuit. 1
Sent to 5. When the reproduction signal is input, the tracking error detection circuit 15 alternately selects the reproduction signals of the A1 and B1 heads by the switch SW3 each time the switching pulse 18 is switched, and inputs the reproduction signal. Called signal 16. Therefore, the ATF pilot signals input to the tracking error detection circuit 15 are f1 and f3 from FIG. 3, and the tracking error detection circuit 15 receives the crosstalk from the left and right adjacent tracks when one of these signals is input. An ATF error (tracking error) signal 14 indicating component bias is output to the tracking control circuit 13.

The ATF error signal 14 is subjected to gain adjustment and phase compensation by the tracking control circuit 13 and then added to the signal output from the capstan rotation speed control circuit 11, and this addition signal is added to the motor drive amplifier 10.
Entered in. The motor drive amplifier 10 controls the rotation of the capstan motor 8 according to the input signal so that the ATF error signal becomes zero. Capstan motor 8
Is transmitted to the tape 7 by the pinch roller 6 and causes the tape 7 to run in the direction of arrow B in the figure. At this time, the running phase of the tape 7 is controlled by the tracking control circuit 13 to run the tape 7. The phase (tracking) is kept constant.

According to the present embodiment, the four on the rotary cylinder 3
For the heads A1, A2, B1, B2, the ATF pilot signal f1 is supplied to the head A1, and the ATF pilot signal f is supplied.
2 is supplied to the head A2, the ATF pilot signal f3 is supplied to the head B1, the ATF pilot signal f4 is supplied to the head B2, and the heads A1 and A2 (head B
By providing a time difference corresponding to the angle division Δθ of 1, B2), the ATF pilot signal is recorded on the tape 7 as f1,
Recording can be performed in the order of f2, f3, and f4. Therefore, it is possible to perform the tracking control using the pilot signals f1 and f3 reproduced by the heads A1 and B1 among the ATF pilot signals recorded in this way, and it is possible to perform high tracking control for four heads as in the conventional case. Accurate tracking control can be performed.

The video signal generation source 22 of the above embodiment generates the two-channel video signals 101 and 102, and the delayed video signal 20 output from the delay circuit 23.
The same effect can be obtained even if the components 1 and 202 are generated from the video signal generation source 22. Further, at the time of reproduction in the above-mentioned embodiment, the tracking control was performed based on the reproduction signal obtained from the heads A1 and B1,
Tracking control can also be performed using a reproduction signal obtained from any one or two heads of 2, B1 and B2. Further, in the above embodiment, the pilot signals f1 and f generated from the ATF pilot signal generator 20-2 are used.
4 is the angle division Δθ of the heads A1 and A2 with respect to the pilot signals f1 and f3 generated from the signal generator 20-1.
However, if the sampling of the pilot signal may deviate from the center value, the same effect can be obtained without the time delay.

[0021]

As described above in detail, according to the present invention, 4
By supplying the frequency ATF method to the four heads on the rotary cylinder that simultaneously record and reproduce on two channels and superimpose and record the video signal on the tape, the tracking control of the four heads can be performed with high accuracy during reproduction.

[Brief description 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 time chart showing the operation of the device shown in FIG.

3 is a diagram showing a trace pattern by the device shown in FIG.

FIG. 4 is a block diagram showing an example of a conventional magnetic recording / reproducing apparatus.

5 is a block diagram showing a detailed example of the tracking error detection circuit shown in FIG.

FIG. 6 is a time chart showing the operation of the apparatus shown in FIG.

7 is a diagram showing a trace pattern by the device shown in FIG.

[Explanation of symbols]

1, 2 ... Inclined post 3 ... Rotating cylinder 4 ... PG 5-1 to 5-4
... rotary transformer 6 ... pinch roller 7 ... magnetic tape 8 ... capstan motor 9 ... speed detector 10 ... motor drive circuit 11 ... rotation speed control circuit 12, 31-34 ... adder 13 ... tracking control circuit 14 ... ATF error signal 15 ... Tracking error detection circuit 16 ... Reproduction RF signal 17 ... SWP generation circuit 18 ... SWP 19 ... Clock 20-1, 20-2 ... ATF pilot signal generator 22 ... Video signal generation source 23 ... Delay circuit A1, A2, B1 , B2 ... Heads SW1 to SW5
…switch

Claims (7)

[Claims] 1. Heads A1, A on the outer periphery of a rotary cylinder.
2 are arranged 180 degrees opposite to each other, and heads B1 and B
2 are arranged opposite to each other by 180 degrees, and the heads A1 and A2 and the heads B1 and B2 are arranged close to each other by providing a step of Δθ angle division, and by these 4 heads, two-channel video signals are simultaneously recorded on the tape. In a magnetic recording / reproducing apparatus for recording / reproducing, a pilot signal f of four frequencies is recorded at the time
1, f2, f3, f4, pilot signal generating means, pilot signal f1 generated by the pilot signal generating means to the head A1, pilot signal f2 to the head A2, pilot signal f3 to the head B1. And a pilot signal supplying means for supplying the pilot signal f4 to the head B2 by superimposing it on the video signal. 2. The pilot signal generating means shifts the generation times of the pilot signals f1 and f3 from the generation times of the pilot signals f2 and f4 by a time corresponding to the angle division of Δθ. Magnetic recording device. 3. Heads A1, A on the outer peripheral portion of the rotary cylinder.
2 are arranged 180 degrees opposite to each other, and heads B1 and B
2 are arranged opposite to each other by 180 degrees, and the heads A1 and A2 and the heads B1 and B2 are arranged close to each other by providing a step of Δθ angle division, and by these 4 heads, two-channel video signals are simultaneously recorded on the tape. In a magnetic recording / reproducing apparatus for recording / reproducing, at the time of reproduction, selecting means for selecting a reproducing signal obtained from any one or any two of the four heads, and left and right adjacent to the reproducing signal obtained by the selecting means. By extracting the crosstalk component of the pilot signal reproduced on the track, an error detection means for detecting the control signal corresponding to the imbalance of these crosstalk components, and based on the error signal detected by this error detection means A magnetic reproducing apparatus comprising: a control unit that controls a running phase of the tape. 4. The selecting means is provided for the rotary cylinder.
4. The magnetic recording / reproducing apparatus according to claim 3, wherein two heads mounted facing each other by 08 degrees are selected. 5. Heads A1, A on the outer peripheral portion of the rotary cylinder.
2 are arranged 180 degrees opposite to each other, and heads B1 and B
2 are arranged 180 degrees opposite to each other, and the sets of the heads A1 and A2 and the heads B1 and B2 are arranged close to each other with a step divided by Δθ, and a video signal of 2 channels is recorded on the tape by these 4 heads. In a magnetic recording / reproducing apparatus for recording / reproducing simultaneously, pilot signal generating means for generating four-frequency pilot signals f1, f2, f3, f4 during recording, and a pilot signal f1 generated by this pilot signal generating means for the head A1. , The pilot signal f2 to the head A2, the pilot signal f2
3 for the head B1 and pilot signal f4 for supplying the pilot signal f4 to the head B2 by superimposing it on the video signal, and a reproduction signal obtained from any one or any two of the four heads during reproduction. And a control signal corresponding to the imbalance of the crosstalk components by extracting the crosstalk components of the pilot signals reproduced on the left and right adjacent tracks from the reproduction signal obtained by the selection device. A magnetic recording / reproducing apparatus comprising: an error detecting means for detecting; and a control means for controlling a running phase of the tape based on an error signal detected by the error detecting means. 6. The pilot signal generating means generates the generation times of pilot signals f1 and f3 and the pilot signals f2 and f.
4. The magnetic recording apparatus according to claim 1, wherein the generation time of No. 4 is shifted by a time corresponding to the angle division of Δθ. 7. The selecting means includes one unit for the rotating cylinder.
5. The magnetic recording / reproducing apparatus according to claim 4, wherein two heads mounted facing each other by 08 degrees are selected.