JPS6142762A - Magnetic picture recording and reproducing device - Google Patents

Abstract

PURPOSE:To make the titled device suitable for a 4-head type magnetic picture recording and reproducing device by forming a controlled signal fed to a cylinder position control circuit and a head switching signal by means of a turning phase detecting output and a turning information detecting output of a magnetic head of a rotary head cylinder. CONSTITUTION:A magnetic tape 4 is wound on a rotary head cylinder 3 on which magnetic heads 21-24 with different azimuth angle while being separated at 90 deg. each and a signal is recorded or reproduced. A PG7 detecting the rotating phase of the cylinder 3 gives an output to a 1/3 frequency division circuit 28 and an FG6 detecting the turning information of the cylinder 3 gives an output to a 1/3 frequency division circuit 29. The output circuit 29 of the circuit 28 is reset and the circuit 29 gives an output to a delay circuit 30. The 2nd delay output of the circuit 30 is given to a 1/2 frequency divider 26 and the result is transmitted from an output terminal 27 to a cylinder position control circuit. Further, the output of the circuit 30 is fed to a 4-phase head switching signal generating circuit 31 and the heads 21-24 are switched at recording and reproducing. Thus, the device is suited to the 4-head magnetic picture recording and reproducing device and also to circuit integration.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a magnetic recording and reproducing device.

Conventional Structure and Problems Therein FIG. 1 shows a block diagram of a magnetic head switching signal generating circuit in a two-head type magnetic recording/reproducing apparatus, and FIG. 2 shows waveforms of various parts in FIG. 1.

In FIG. 1, a magnetic tape 4 is wound approximately 1800 times in the direction of arrow 6 around a rotary head cylinder 3 having magnetic heads 1°2 with different azimuth angles, and is run.
, 2 record or reproduce video signals on the magnetic tape 4. On the other hand, a signal S1 from a frequency generator (hereinafter referred to as FG) 6 that detects rotation information of the rotary head cylinder 3 is input to a clock terminal of a frequency dividing circuit 8. In addition, a rotational phase detector (
The O signal S2 from PG (hereinafter referred to as PG) is input to the reset terminal of the Z frequency divider circuit 8, and the output signal S3 of the frequency divider circuit 8 is input to the delay circuit 9, which is connected to a resistor R that determines the delay time of the delay circuit 9. and capacitor C are connected in series from the power supply +v0° and grounded, and by adjusting the charging time constant, the signal S4 is generated. By adjusting the resistor R, the phases of the magnetic heads 1 and 2 and the phase of the head switching signal S6 are changed. Match. The output signal S5 of the delay circuit 9 is input to the clock terminal of the % frequency divider circuit 10, and the output signal S2 of PG 7 is input to the reset terminal of the % frequency divider circuit 10 to obtain the output signal S6. The signal is output from the magnetic heads 1 and 2 and used as a switching signal for the magnetic heads 1 and 2.

According to the above-mentioned conventional example, the rotating two-head type magnetic recording/reproducing device can continuously record and reproduce each field or frame of the video signal, but since the diameter of the rotating head cylinder becomes large, the device The disadvantage is that it is not suitable for miniaturization and weight reduction.

OBJECTS OF THE INVENTION It is an object of the present invention to create a magnetic head switching signal and a controlled signal to be supplied to a rotary head cylinder phase control circuit in a four-head type magnetic recording/reproducing apparatus that solves the above-mentioned conventional problems.

Structure of the Invention The present invention provides a 4-head magnetic recording and reproducing apparatus, which includes a % frequency dividing circuit for dividing the frequency of a PG multiplied signal of a rotary head cylinder by %;
The FG multiplied signal of the rotary head cylinder is used as a clock input, and the output of the frequency dividing circuit is input to a delay circuit that can set a reset time, and the second delay time output of the delay circuit is used as a clock input, and the frequency dividing circuit of the previous symbol is input as a reset input. A controlled signal for the rotary head cylinder phase control circuit is created by a Z frequency divider circuit, and during recording, the first and third delay time outputs of the delay circuit are used as clock inputs, and the output of the Z frequency divider circuit is used as a reset input. a first 4-phase head switching signal generation circuit; and a second 4-phase head switching signal generation circuit that uses the second delay time output of the delay circuit as a clock input and the output of the pre-symbol frequency divider circuit as a reset input during playback. This is what we provide.

Description of examples An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 shows a block diagram of a magnetic head switching signal generation circuit and a controlled signal generation circuit for a rotary head cylinder phase control circuit in a four-head magnetic recording and reproducing apparatus, which is an embodiment of the present invention, and FIG. 4 shows each component. The waveform of is shown.

In FIG. 3, magnetic heads 21 with equal azimuth angles.
A magnetic tape 4 is wound about 270 degrees in the direction of arrow 6 around a rotary head cylinder 3 provided with a magnetic head 22.24 having an azimuth angle opposite to that of the magnetic heads 21.23 separated by 90 degrees. The video signal is recorded or reproduced on the magnetic tape 4 by the magnetic heads 21, 22, 23, 24.

The signal S22 from the FG7 that detects the rotational phase of the rotating head cylinder 30 is divided by % by the % frequency dividing circuit 28 to produce a signal S23.
get. F detects rotation information of the rotating head cylinder 3
A signal S21 from G e is input to the clock terminal of the % frequency dividing circuit 29, and the output signal S23 of the % frequency dividing circuit 28 is %.
It is input to the reset terminal of the frequency divider circuit 29, and the % frequency divider circuit 2
The output signal S24 of 9 is input to the delay circuit 3Q, and a resistor R and a capacitor C, which determine the delay time of the delay circuit 30, are connected in series from the power supply terminal co, one end of the capacitor C is grounded, and the charging time constant is The signal S2. So, the first
．． By setting the second and third threshold voltages,
Delay circuit output signals S26' S2□ and S28 are obtained.

The second delay time output signal S2□ of the delay circuit 30 is input to the clock terminal of the A frequency divider circuit 26, and the output signal S23 of the Z frequency divider circuit 28 is input to the reset terminal.
29 is supplied to the rotating head cylinder phase control circuit from the output terminal 27, and during recording, the phase is compared with the vertical synchronization signal of the video signal to be recorded, and during playback, the phase is compared with the reproduction reference signal to determine the rotational phase of the rotating head cylinder 3. is under control.

On the other hand, the output signal S26. of the delay circuit 3o. S2□.

S28 is input to the four-phase head switching signal generation circuit 31,
Signal S3゜#831+”32 during recording and playback
1 Obtain S33.

FIG. 5 shows a circuit diagram of an embodiment of the four-phase head switching signal generation circuit 31, FIG. 6 shows waveforms of various parts during recording, and FIG. 7 shows waveforms of various parts during reproduction. In FIG. 6, the output signal 5281S271S28 of the delay circuit 30 is input to the input terminal 41°42.43, and the switch 4
According to 4.46, signals S26 and S28 are used during recording, and only signal S27 is used during playback. D type flip-flop with reset terminal 47, 48.4
9 and the NOR gate 46 constitute a first four-phase ring counter, and when recording as a clock signal, the signal S28
When reproducing the signal, the signal S2a is inputted, and the reset signal is inputted from the input terminal 58 as the output signal S23 of the % frequency dividing circuit 28. Similarly, type 7 lip 70 knob 5 with reset terminal
5, 56, 57, and NOR7, the signal S2□ is input, and the reset signal is the signal S23. When the reset signal S23 becomes high level, all reset terminal D type flip 70 tabs 47.48.49.55.56.
Since the outputs Q of 57 are all low level, the outputs of NOR gates 46 and 54 are high level. Thereafter, the high level is shifted to the right according to the clock input signal, and the signals S411 S42 P S43 T S44 and the signals S4. , S46. S4□ and S48 are created. The OR gates 50, 51, 52, and 53 are busy ORing the in-phase timing components of each four-phase ring counter.

Output signal S301 of 4-phase head switching signal generation circuit 31
"311" 321833 is input to the recording/reproducing amplifier 25, and during recording, the magnetic heads 21, 22, 23° 24
With the switching of the recording current to
), and during playback, the playback output from the magnetic tape 4 is sent to the magnetic heads 21, 22, 23, 24.
The head position is adjusted by adjusting the resistance R'f of the delay circuit 30 so that the switching timing is at the position of
The reproduction output of each head is obtained every 2,700 times.

Effects of the Invention According to the present invention, in a four-head magnetic recording/reproducing apparatus, the FG and PG of the rotary head cylinder create a magnetic head switching signal and a controlled signal to be supplied to the rotary head cylinder phase control circuit. It is possible to provide a system suitable for a four-head type magnetic recording/reproducing device and suitable for integration into an integrated circuit. Also, the FG frequency of the rotating head cylinder is 3-M-fV (M: positive integer, fv
: Vertical synchronization signal frequency), the frequency of the controlled signal supplied to the rotating head cylinder phase control circuit can be increased by %.
fv, and the control characteristics of the phase control of the rotary head cylinder are improved.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a magnetic head switching signal generation circuit in a two-head type magnetic recording/playback device, Fig. 2 is a waveform diagram of each part in Figs. A block diagram of a magnetic head switching signal generating circuit and a controlled signal generating circuit for a rotary head cylinder phase control circuit in a magnetic recording/reproducing apparatus, FIG. 4 is a waveform diagram of each part in FIG. 3, and FIG. 6 is a magnetic head switching signal generating circuit of the present invention. A circuit diagram of an embodiment of the four-phase head switching signal generation circuit in the head switching signal generation circuit, FIG. 6 is a waveform diagram of each part during recording in FIG. 6, and FIG. 7 is a waveform diagram of each part during reproduction in FIG. 6. A waveform diagram is shown. 1.2...magnetic head, 3...rotating head cylinder, 4...magnetic tape, 5...
...Arrow, 6...FG. 7...PG, 8...% frequency dividing circuit, 9.
Old...delay circuit, 1o...% frequency divider circuit, 11...
...Output terminal, 21゜22.23.24...
...magnetic head, 25...recording/playback amplifier,
26...% frequency divider circuit, 2γ...output terminal, 28...Z frequency divider circuit, 29...%
Frequency divider circuit, 30...Delay circuit, 31...
・4-phase head switching signal generation circuit. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure B Figure 2] Figure 3 Figure 4 Figure 5 Figure 6

Claims (2)

[Claims] (1) 360 magnetic heads with different azimuth angles alternately
A rotary head cylinder spaced apart by °/N (N: number of magnetic heads), a magnetic tape on which information is recorded and reproduced by the magnetic head of the rotary head cylinder, and a rotary head cylinder that detects the rotational phase of the magnetic head. a phase detector; a rotation information detector that detects rotation information of the magnetic head;
1/ which divides the rotational phase detector output by 1/(N-1)
(N-1) frequency dividing circuit and the rotation information detector output to 1/
[M(N-1)] (M: positive integer), and the above 1
/(N-1) 1/[ which can be reset by the frequency divider circuit output
M(N-1)] frequency dividing circuit and the 1/[M(N-1)]
a delay circuit that can set first, second, and third delay times that take the frequency divider circuit output as input; and a delay circuit that takes the second delay time output as input and outputs the 1/(N-1) frequency divider circuit; and a 1/2 frequency divider circuit that can be reset by a 1/2 frequency divider circuit, and during recording, the first and third delay time outputs and the 1/(N-1) frequency divider circuit output are supplied to the N magnetic heads as inputs. a first four-phase signal generation circuit for switching the recording current to be recorded; and a reproduction of the N magnetic heads, which receives the second delay time output and the 1/(N-1) frequency division circuit output during reproduction. a second four-phase signal generation circuit for switching the output;
The frequency dividing circuit output is supplied to the servo circuit, and the first and second
A magnetic recording/reproducing device characterized in that four magnetic heads are switched by the output of a four-phase signal generating circuit. (2) The frequency of the rotation information detector is M・(N-1)・f_
2. The magnetic recording and reproducing apparatus according to claim 1, wherein the frequency is V (f_v: vertical synchronizing signal frequency).