JPS62266755A - Rotary head type magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To switch plural heads with high accuracy without reference to the rotating speed of a rotary drum by setting the number that a pulse counting means counts in conformity with the number of rotary heads and their fitting positions. CONSTITUTION:A drum PG signal outputted by a FG detector 12 is inputted to the data input terminal of a shift register 17 and a drum FG signal outputted by a FG amplifier 9 is inputted to the clock input terminal of the register 17 respectively. The register 17 outputs its output signal to a gate circuit 17 every time the number of pulses corresponding to the playback period of respective heads 3a-3d is inputted while the output is delayed by the number of pulses equivalent to a time difference corresponding to the fitting position shift between a pulse generator 8 and rotary heads 3a and 3b, and 3c and 3d. The circuit 18 outputs a switching signal for a switch 5, which switches the outputs of the heads 3a-3d and outputs it to a terminal 6 as a continuous signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a single-rotation head type magnetic recording and reproducing device, and more specifically, the wrap angle at which the tape is wound around the rotary head drum is 180' or less, and a plurality of ( The present invention relates to a head switching signal generating means for a rotary head type magnetic recording/reproducing device having three or more rotating heads.

[Prior Art] Fig. 3 is a block circuit diagram of a reproducing system of a conventional two-head rotary head type magnetic recording/reproducing apparatus disclosed in, for example, Japanese Patent Application Laid-Open No. 59-191109. In figure 0, which has an angle of 90°, (1) is a drum motor,
(2) is a rotary head drum rotationally driven by this drum motor (1), (3a) and (3b) are rotary heads disposed opposite to the drum (2), (4a)
, (4b) is a regenerative amplifier that amplifies the reproducing signals of the rotating heads (3a) and (3b).

(5) is a switch circuit, which includes regenerative amplifiers (4a), (
Select the output from 4b). (6) is the output terminal, (7
) is the frequency generator (FG), (8) is the pulse generator (PG), (9) is the FG #3 spanner, (lO) is the speed control blade, (11) is the driver, (12) is the PG detection Vessel, (1
3) is a trapezoidal wave generator, (14) is a reference oscillator, (15
) is a phase comparator, and (1B) is a delay circuit.

Next, the operation will be explained. FIG. 4 is an operation timing diagram of this conventional example.

For the drum servo, a frequency generator fi (FG) (7) and a pulse generator (
PG) (8) is provided and the output signal of the single frequency generator (7) is amplified by the FG amplifier (8)? &(Drum FG
The output signal from this speed controller (10) is supplied to the drum motor (1) via the driver (11) and substantially controls the rotation of the motor. The rotational speed is controlled to be constant by a signal with a frequency corresponding to the speed.

On the other hand, a pulse is obtained from the pulse generator (8) for each rotation according to the rotation of the drum motor (1), which is detected by the PG detector (12), and based on this pulse, a trapezoidal wave generator ( 13), a trapezoidal wave is formed, and the slope part of the trapezoidal wave is extracted by the reference signal from the reference oscillator (14), that is, the sampling pulse, in the phase comparator (15), and is converted into a pulse from the pulse generator (8). An error signal is obtained by comparing the phase between and the reference signal.
This error signal is transmitted to the speed controller (lO) and driver (11).
) is supplied to the drum motor (1), and the rotational phase of the drum motor (1) is controlled.

Also, to switch the switch circuit (5).

A pulse generator (
8) and the rotary heads (3a) and (3b), a delay circuit (16) such as a flip-flop circuit is provided, which has a delay time t depending on the positional deviation.

After the pulse from the PG detector (12) (hereinafter referred to as drum PG signal, shown in Fig. 4) is delayed by a predetermined + in the delay circuit (16) (as shown in Fig. 4), it is output as a switching signal. The rotating head (3) is supplied to the switch circuit (5) and amplified by the regenerative amplifiers (4a) and (4b).
Reproduction signal output A of a) and (3b).

B (shown in figure ffi4) is switched and the output terminal (
8) as a signal shown in FIG. 4(E).

[Problems to be Solved by the Invention] Since the conventional rotary head type magnetic recording/reproducing device is configured as described above, it is fine if there are two heads per rotation.
In the case of a device having three or more rotating heads, a circuit is required to generate switching signals for a plurality of rotating heads corresponding to the number of rotating heads from the drum PG signal output from the PG detection rh (12). However, in order to accommodate the variable speed rotation of the rotary head drum (2), the circuit becomes even more complicated and expensive.

This invention was made to solve the above problems, and the mechanical configuration, that is, the mounting position and structure of the pulse generator, remains the same as the conventional 2-head.
The object of the present invention is to obtain a rotary head type 1A recording/reproducing device which can switch between a plurality of rotary heads.

[Means for Solving the Problems] The rotary head type magnetic recording/reproducing device according to the present invention is reset by a drum PG signal output from a pulse generator (PG), and uses clock pulses output from a frequency generator. This device is characterized in that it includes a pulse counting means that outputs a signal every time a predetermined number of counts is counted, and a gate circuit that outputs a switching signal for the rotary head based on this counting signal.

[Operation] The pulse counting means in the present invention counts the number of drum FG signals from the time when the drum PG signal is input, and outputs a switching signal for the rotary head every time a predetermined number is counted. Therefore, by setting the number counted by the pulse counting means in accordance with the number of rotating heads and the mounting position, switching of three or more heads can be performed with high accuracy regardless of the rotational speed of the rotating drum. .

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1st
The figure is a block circuit diagram of a reproducing system of a rotary head type magnetic recording and reproducing apparatus which is an embodiment of the present invention, and FIG. 2 is a timing diagram thereof. In FIG. It shows.

In this example, it is assumed that there are four rotating heads, each of which is attached at 90 degree intervals.

In the figure, (3c) and (3d) are rotating heads (3a).

Together with (3b), there are 4 heads. (4c),
(4d) is a regenerative amplifier that amplifies the reproduced signals of the rotary heads (3c) and (Id), and the switch circuit (5) selects the output of the regenerative amplifiers (4a) to (4d) and selects the output terminal ( 6) Output.

(17) is a pulse counting means, in this example, a shift register which uses the drum FG signal as a clock input and a drum PG signal as a data input; (18) is a shift register (
The output of 17) is input, and this causes 4 heads (3
This is a gate circuit that generates a switching signal rotated at the reproduction timings of a) to (3d) and inputs it to the switch circuit (5).

Next, the operation of this embodiment will be explained.

The drum PG signal output from the PC detector (12) is
A signal synchronized with the rotation of the drum (2) as shown in FIG. 2(A) is input to the data input terminal of the shift register (17). On the other hand, the drum FC signal output from the FG# [device (9) is a signal with a higher frequency than the drum PG signal, as shown in FIG.
7) is input to the clock input terminal. The shift register (17) includes a pulse generator (8) and a rotary head (
3a), (3b), (3c), and (3d) due to the delay in the number of pulses corresponding to the time difference t according to the deviation in the mounting position. And each rotating head (3a) to (3d)
An output signal is output to the gate circuit (18) every time the number of pulses corresponding to the reproduction period is input.

The gate circuit outputs the switching signals (a) to (d) of the switch (5) at the timing shown in the second V4 (C) to (F), and the switch (5) outputs the switching signals (a) to (d) of the rotary head (3a) to (3d).
) output terminal (8) as a continuous signal as shown in FIG.
).

In addition, although the case of four rotating heads was shown in the above embodiment, a similar configuration can be made if a plurality of (three or more) rotating heads are used.

Further, in the above embodiment, a shift register (17) is used as the pulse counting means, but a counter may also be used. In this case, the counter is reset by the drum PG signal, and the drum FG signal is input to Every time you count,
The configuration may be such that the output signal is sent to the gate circuit (18).

Further, in the above embodiment, the case of a reproduction system has been described, but it can be similarly applied to a recording system, and similar effects can be obtained.

[Advantage of the invention 1] As described above, according to the present invention, switching signals for a plurality of rotary heads are inputted into two signals, the drum PC signal and the drum FG signal used for the servo of the rotary head drum, and counted. A head switching signal is generated between the circuit and the gate circuit, and this switching signal causes the head to rotate.

Since the playback output of the RAD is switched and output, an inexpensive rotary head type magnetic recording and reproducing device that has a simple configuration and can perform highly accurate head switching that can respond to changes in the speed of the rotary head drum can be created. There are benefits to be gained.

[Brief explanation of drawings]

Fig. 1 is a block circuit diagram showing the configuration of an embodiment of the present invention, Fig. 2 is a timing diagram of this embodiment, and Fig. 3 is a block diagram showing the configuration of a reproducing system of a conventional rotary head type magnetic recording/reproducing device. The circuit diagram and FIG. 4 are timing diagrams of this conventional example. (2)...Rotating drum, (3a) to (3d)...
Magnetic head, (7)...Frequency generator, (8)...
Pulse generator, (17)...Shift register (
(pulse counting means), (18)...gate circuit. Note that in each figure, the same reference numerals indicate the same parts.

Claims (3)

[Claims] (1) The wrap angle is 180° or less, three or more magnetic heads are arranged on the rotating drum, a pulse generator detects the rotational phase of the rotating drum, and a pulse generator is proportional to the rotational speed of the rotating drum. a frequency generator that outputs a pulse signal at a frequency, and is configured to perform servo control of the rotating drum using the output signal of the pulse generator and the output signal of the frequency generator. The apparatus includes a pulse counting means which uses the output signal of the pulse generator as a data input and the output pulse of the frequency generator as a clock input, and switches the reproduction output of the plurality of magnetic heads based on the output of the counting circuit. What is claimed is: 1. A rotary head type magnetic recording/reproducing device comprising: a gate circuit for outputting a head switching signal to be outputted; (2) The pulse counting means is composed of a shift register, and this shift register sends a signal to the gate circuit every time a predetermined number of clock signals are input from the frequency generator from the time when the pulse generator signal is input. A rotary head type magnetic recording/reproducing apparatus according to claim 1, which is configured to output. (3) The pulse counting means is composed of a counter,
The counter is configured to be reset by a pulse generator signal and output a signal to the gate circuit every time it counts a predetermined number of clock signals input from the frequency generator. Rotating head type magnetic recording and reproducing device.