JPS61111082A - Revolving head type recording or reproducing device - Google Patents

Abstract

PURPOSE:To facilitate easy control of the rushing phase of a revolving head in relation to the recording medium by providing a mean to generate the primary periodic signal synchronized with the rotation of the revolving head, a mean to generate the secondary periodic signal related to the medium-transferring operation, and a mean to control the medium-transferring operation based on the phase difference between the two periodic signals. CONSTITUTION:In the normal reproducing, a signal of 30Hz that is synchronized with the capstan FG is obtained from a frequency divider 28. In case of the (n) time speed search reproduction, the signal is frequency-divided to 1/n by a frequency divider 31, so that a signal of 30Hz is obtained in the n-time speed search reproducing, and the divided signal is supplied to a phase comparator 34. Meanwhile, as the other input to the phase comparator 34, a signal of 30Hz of drum PG is supplied. The capstan phase controlling signal if obtained from the signals above. In consequence, a drum motor 5 rotates one turn at every run of n-track of a tape 1 driven by a capstan 2, by which the rushing phase of heads 4a and 4b against the track becomes approximately constant. Therefore, the position of the noise on the picture plane becomes constant when the high speed search is performed. In such a manner as above, the rushing phase of the head against the revolving head is made able to be controlled by the mean with extremely simple formation.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a rotary head type recording or reproducing device, and in particular to a device for recording or reproducing signals by sequentially tracing a recording medium at a predetermined pitch with a rotary head. It concerns the control of transport.

(Description of the Prior Art) This type of rotary head type device includes a video tape recorder (VTR), a digital audio tape recorder (
In this specification, a so-called helical scan type VTR will be explained as an example.

FIG. 1 is a block diagram showing the configuration of a servo system of a conventional VTR. In FIG. 1, l is a magnetic tape, 2 is a capstan for running the tape 1 in its longitudinal direction, and 3 is a magnetic tape.
A pinch roller pinches the tape 1 together with the capstan 2, 4a and 4b are rotary heads for recording and reproducing video signals, and 5 is a drum motor for rotating the heads 4a and 4b.

First, the operation during recording will be explained. A drum rotation speed detection signal (drum FC) generated by the rotation speed detector 7 of the drum motor 5 is supplied to a drum speed control circuit 8, which obtains a drum speed control signal. On the other hand, the drum rotational phase detection signal (drum PG: 30Hz) detected by the rotational phase detector 6 of the drum motor 5 is supplied to the phase comparison circuit 9.1 The other input of the phase comparison circuit 9 is the terminal 12. A vertical synchronizing signal (V D
) is inputted via the R side terminal of the switch 14 to the zero phase comparison circuit 9, which compares the phases of the drums PG and VD, and obtains a drum phase control signal based on the phase difference between them. The drum phase side u4@ and the drum speed control signal are added at an appropriate ratio in an adding circuit 10, and the drum motor drive circuit 11 is controlled by this added signal, so that the drum motor is driven at a predetermined speed (30Hz).
), rotates at a predetermined phase.

Also, at this time, the VD separated by the VD separation circuit 13 is CTL
A signal synchronized with VD generated by the generating circuit 16 is supplied to the control head 18 via the R side terminal of the switch 17, and a control signal (cT
L) is recorded on the end of the tape 1.

On the other hand, the capstan rotation speed detection signal (capstan FG) generated by the rotation speed detector 7 of the capstan motor 23 is supplied to the capstan speed control circuit 26, whereby the capstan speed obtained from the circuit is The control signal is supplied to an adder circuit 27. Now, if the capstan FG is 240 Hz, the frequency is divided by 178 by the frequency divider 28, and a 30 Hz signal synchronized with the capstan FG is supplied to the phase comparison circuit 21 via the R side terminal of the switch 22. The 30 Hz reference clock generated by the reference oscillator 15 is supplied as the other input of the 0 phase comparison circuit 21 through the Nfl11 terminal of the switch 20.
A phase control signal is formed and added to the aforementioned capstan speed control 1@ in an adder circuit z7, and the added signal controls the capstan motor 23 via the capstan motor drive circuit 25.

Next, the operation during playback will be explained. During reproduction, the phases of the drum PG and the reference clock supplied from the reference oscillator 15 via the switch 14 are compared in the phase comparator circuit 9, and in order to form the drum phase control signal by this, the drum motor 5 is Head 4a, 4b 30) 1z
It will rotate at a constant speed.

In addition, the capstan phase control signal changes the phase between the reference clock obtained from the N-side terminal of the switch 20 and the reproduced CTL that is regenerated by the head 18 and obtained via the P-side terminal of the switch 17 and the N-side terminal of the switch 19. It is obtained by phase comparison in the comparator 21. Therefore, the capstan motor 23 is driven so that the phase of the reproduction CTL is locked to the rotational phase of the drum motor 5. Therefore head 4
a and 4b will accurately trace the recording track.

Let us now consider the case where a so-called high-speed search is performed, in which the tape 1 is played back while running at high speed. In this case, the control of the drum motor 5 is exactly the same as during normal reproduction, and the drum motor 5 rotates the heads 4a, 4b at a constant speed of 30 revolutions per second.

On the other hand, the rotational speed of the capstan 2 must be set to n times that of normal reproduction.Accordingly, after the reproduction CTL is divided by l/n by the frequency divider 29, the S side terminal of the switch 19 is The signal is supplied to the phase comparator 21 via the phase comparator 21. On the other hand, the drum PG itself is used as the signal for phase comparison with this,
The phase of the capstan motor is controlled by this phase comparison output. Therefore, the capstan motor 23 is driven so that the phase of the signal obtained by dividing the reproduced CTI by l/n is locked to the rotational phase of the drum motor 5. . As a result, the tape entry positions of the heads 4a and 4b are always constant with respect to the track, so the position where noise appears on the search screen is also constant.

However, such a servo circuit configuration is based on the premise of recording and reproducing CTL, and cannot be used in recently proposed formats that do not record and reproduce CTL.For example, the well-known four-frequency pilot system cannot be used. When performing tracking during normal playback, the rotational phase of the capstan motor 23 cannot be controlled during high-speed search.

(Object of the Invention) The present invention has been made in view of the drawbacks inherent to the conventional rotary head device as described above, and is a rotary head type device that can extremely easily control the phase of entry of the rotary head into the recording medium. The purpose is to provide recording or playback equipment.

<Description by Example> An example in which the present invention is applied to a servo system of a VTR will be described below.

FIG. 2 is a block diagram showing the configuration of a servo system of a VTR as an embodiment of the present invention. Components in FIG. 2 that are the same as those in FIG. 1 are given the same numbers, and explanations thereof will be omitted.

The operation during recording is similar to that of the VTR shown in FIG. 1, except that CTL is not recorded.

Regarding the drum servo during normal playback, the V
Similar to TR, the drum phase control signal is obtained by comparing the phase of the drum PG with a 30 Hz reference clock obtained from the reference oscillator 15.

At this time, the capstan phase control signal is obtained by the ATF signal generation circuit 3o using a well-known method. The terminal 36 is a terminal to which a signal reproduced by the heads 4a and 4b is input, and this reproduced signal is supplied to the ATF signal generation circuit 30. In the ATF signal generation circuit 30, the head 4
A and 4b are cross-streets of pilot signals obtained from tracks on both sides adjacent to the track mainly traced.
A tracking error signal (ATF signal) is obtained by comparing the levels of the components.

This ATF signal is also supplied to the adder circuit 27 via the P-side terminal of the switch 35 as a capstan phase control signal.

However, this ATF signal is difficult to use during a high-speed search in which reproduction tracks are changed one after another.

Therefore, the operation during high-speed search will be explained next. The drum is controlled in the same way as during normal playback, so a description thereof will be omitted.

A phase comparator circuit 34 for generating a capstan position control signal includes a capstan FG which is frequency-divided by a frequency divider 2B.
Furthermore, the 0 frequency divider 28, to which the signal frequency-divided by the frequency divider 31 is supplied via the S-side terminal of the switch 32, provides a 30 Hz signal synchronized with the capstan FC during normal playback, as described above. , when performing n-times speed search reproduction, this is further divided by 1/n by a frequency divider 31 to obtain a signal which becomes 30 Hz during n-times speed search reproduction, and supplies it to the phase comparator 34. On the other hand, the aforementioned drum PG (30 Hz) is supplied as the other input of the 1-phase comparator 34, and a capstan phase control signal is obtained from these.

As a result, the drum 5 rotates once every time the capstan 2 runs the tape 1 for n tracks, and the entry phase of the heads 4a and 4b relative to the track becomes almost constant, so that when performing a high-speed search, the drum 5 rotates once. The position of the noise is almost constant.

At this time, the drum PG and the output of the frequency divider 31 are compared in phase, but even if the phase is compared with the output of the reference clock obtained from the reference output side L5, the drum PC
A similar effect can be obtained if it is assumed that the clock and the reference clock are phase-locked.

In addition, even during recording, by comparing the phase of the frequency-divided signal from the capstan FG and the drum PC, and controlling the capstan based on the phase difference, the tape feed amount of the capstan can be adjusted per rotation of the drum. How much can it be stabilized?

(Description of Effects) As described above, according to the present invention, it was possible to obtain a rotary head type recording or reproducing device that can control the phase of entry of the rotary head into the recording medium with an extremely simple configuration.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a servo system of a conventional VTR, and FIG. 2 is a block diagram showing the configuration of a servo system of a VTR as an embodiment of the present invention. 1 is a magnetic tape as a recording medium, 2 is a capstan,
3 is a pinch roller, 4a and 4b are rotating heads, 5 is a drum motor, 6 is a drum rotation phase detector, 23 is a capstan motor, 24 is a capstan rotation speed detector,
25 is a capstan motor drive circuit, 28 is a frequency divider, 3
11 frequency divider, 34 is a phase comparator circuit.

Claims (1)

[Claims] An apparatus for recording or reproducing signals by sequentially tracing a recording medium at a predetermined pitch with a rotating head, the apparatus comprising: a transport means for transporting the recording medium; and a first periodic signal synchronized with rotation of the rotating head. means for generating a second periodic signal related to the medium transport operation of the transport means; and means for generating a second periodic signal related to the medium transport operation of the transport means; A rotary head type recording or reproducing device comprising means for controlling its operation.