JPH0792889B2 - Magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention has a plurality of circuit blocks such as a rotary magnetic head, a recording / reproducing circuit, and a power supply circuit mounted on a rotary cylinder, and records from a magnetic tape. The present invention relates to a magnetic recording / reproducing apparatus that amplifies and selects a reproduction signal on the rotation side.

(B) Conventional Technology In a rotary magnetic head type magnetic recording / reproducing apparatus, a technique of transmitting AC power from the stator side to the rotor side via a rotary transformer of a rotary cylinder and rectifying and smoothing and stabilizing the rotor side is, for example, JP-A-60-5406 (G11B5 / 027)
It is disclosed in the official gazette.

Generally, in a magnetic recording / reproducing apparatus that transmits signals, electric power, etc. through a rotary transformer mounted on a rotary cylinder, one-to-one correspondence is made in each groove of the rotary transformer.
One system of winding is provided for each groove (see Fig. 4).

In FIG. 4, 1a and 1b are fixed side cores and rotary side cores of the rotary transformer, respectively, and power transmission windings 2a and 2b and control signal transmission windings 3a and 3b are provided in the grooves of the cores 1a and 1b, respectively. Recording / reproducing signal transmission windings 4a, 4b, 5a, 5b corresponding to a rotary magnetic head (not shown) are provided.

(C) Problem to be Solved by the Invention In the above circuit configuration, when the number of rotary magnetic heads is increased, or when plural types of control signals and electric power need to be transmitted, winding grooves for the required system are required. The size of the rotary transformer becomes abnormally large, or the distance between the windings becomes narrower and the windings approach each other, causing crosstalk from the adjacent windings. Further, the cost of parts increases due to an increase in the number of grooves in the core of the rotary transformer.

A possible solution to this problem is to reduce the number of grooves in the rotary transformer by arranging windings of multiple systems in the same groove of the rotary transformer.
When the windings for transmission of electric power and the like are superposed, reactance coupling occurs between different types of signal winding pairs and crosstalk occurs.
A method of sharing one winding instead of arranging a plurality of windings in the same winding groove may be considered, but in that case, one end of the winding must be connected to a common ground. When a large current such as an erasing current is supplied to the recording amplifier, the ground potential of the recording amplifier and the control circuit fluctuates and acts on the recording signal, which causes deterioration of image quality during reproduction and malfunction of the control circuit. The winding to which a large current is supplied must be a balanced circuit.

The present invention, without deterioration of image quality and malfunction of the control circuit,
Moreover, it is intended to reduce the winding groove of the rotary transformer.

(D) Means for Solving the Problems The configuration of the present invention is a winding of a plurality of signal systems that are not duplicated and transmitted as signals of the same timing (that is, a winding for an erasing head and a recording / recording / writing head). Playback magnetic head switching,
A winding for control signal transmission such as recording mode switching) is arranged in the same winding groove of the core of the rotary transformer, and signals are transmitted to each winding in time division. .

(E) Operation With the above-described configuration, the control signal also flows to the rotary erasing head during reproduction, but since the magnetic head is not in contact with the magnetic tape, the signal recorded on the magnetic tape is erased. In addition, the erase signal is intermittently driven at the time of recording, the control signal superposed during the period when the erase signal is not supplied is transmitted, and the predetermined erase signal is supplied to the rotary erase head, and the control signal winding is provided. It is possible to separate and extract a recording mode switching signal, a control signal for creating a recording / reproducing switching signal, and the like from the erase signal and the control signal transmitted to the device.

(F) Example Hereinafter, an example of the present invention will be described with reference to the drawings.
FIG. 1 is a circuit block diagram showing a concrete configuration of the present invention, FIG. 2 is a diagram showing waveforms of respective portions of FIG. 1, and FIG. 3 is a sectional view of a rotary transformer of the present invention.

In FIG. 1, 6 is an oscillator for supplying AC power to the rotor side of the rotary cylinder, 7 is a power amplifier for power amplification of the AC signal of the oscillator 6, and 8 is a rotary transformer.
As shown in FIG. 3, it is composed of a core 8a on the stator side and a core 8b on the rotor side, and has power transmission windings 9a and 9b, video RF signal transmission windings 10a and 10b, and an erase signal / control signal modulated wave. It is composed of transmission windings 11a, 11b, 11c. On the rotor side of the rotary transformer, two windings of an erase signal winding 11c and a control signal modulated wave winding 11b are arranged in one groove with respect to the stator side winding 11a. 12 is a rectifier circuit,
13 is a smoothing capacitor, 14 is a voltage stabilizing circuit, 15 is a DC power output terminal, 16a and 16b are recording / reproducing magnetic heads for standard recording mode, 17a, 17b, 22a and 22b are recording / reproducing changeover switches, 1
8a, 18b, 23a, 23b are preamplifiers, 19 and 24 are recording amplifiers, 20,
25 is a head selection switch, 21a and 21b are recording / reproducing magnetic heads for long-time recording mode, 26a and 26b are standard / long-time mode changeover switches, 27 and 29 are buffer amplifiers, 28 is a reproduction RF signal output terminal, and 30 is recording. Signal input terminals, 31a and 31b are switches that are closed during playback and opened during recording, 32a and 32b are switches that are closed during recording and opened during playback, 33 is an RF switching pulse input terminal, 34 is a recording / playback switching signal input terminal, and 35 is standard / long Time mode signal input terminal, 36 is a control signal pulse generation circuit,
37 is an oscillator for erasing signal and control signal is modulated, 38 is a switch which is turned on / off by an output pulse of the control signal pulse generating circuit, 39 is a winding 11a of a rotary transformer, and supplies a signal modulated by the switch. A drive circuit, 40 is a rotary erasing head for erasing two tracks of standard recording, that is, two fields at a time, 41 is a detection circuit for detecting a control signal sent from the stationary side of the rotary transformer, and 42 is the detection signal. 43 is an erase timing pulse input terminal, which is a pulse generation circuit that demodulates the RF switching pulse and generates a recording / reproducing and standard / long-time mode switching pulse.

Next, the operation of the configuration of the present invention will be described. The signal output from the oscillator 6 is power-amplified by the power amplifier 7, and is passed through the power transmission windings 9a and 9b of the rotary transformer 8 to be mounted on the rotating side of the rotating cylinder 12 and the smoothing capacitor 13 and The voltage stabilizing circuit 14 converts the voltage into a predetermined DC voltage, and supplies a predetermined power supply voltage to each circuit on the rotation side.

When an RF switching pulse (Fig. 2 (a)) is input to the terminal 33 during recording or reproduction, a pulse synchronized with the rising edge of the pulse is output from the control signal pulse generation circuit 36 and at the time of recording. After the pulse, a pulse having a width that can be discriminated from the pulse is output, and the pulse is not output at the time of reproduction so as to be a recording / reproduction discrimination signal. Further, when recording / reproducing in the standard recording mode, after the recording / reproducing discrimination pulse, a pulse is outputted in the standard mode and no pulse is outputted in the long time mode. Therefore, the control signal pulse output circuit 36 A pulse as shown in FIG. 2 (c) is output. In the figure, 101 is a pulse indicating the rising position of the RF switching pulse, 102 is a pulse which becomes low level during high level reproduction during recording, and 103 is high level during standard recording / reproducing mode and low during long time recording / reproducing mode. Indicates a pulse that goes to a level.

When the switch 38 is turned on and off by the pulse, the drive circuit 39
The winding 11a of the rotary transformer 8 is driven by, and the modulated wave of the control signal (FIG. 2 (d)) is reproduced at the time of reproduction and is detected by the detection circuit 41 via the winding 11b. In addition to the wave, an erase signal (Fig. 2 (e)) flows.

At this time, a control signal also flows to the rotation erasing head 40,
Since the erasing head 40 is not in contact with the magnetic tape at this timing, there is no fear of erasing the recorded contents on the magnetic tape.

Based on the signal detected by the detection circuit 41 (FIG. 2 (c)), an RF switching pulse (FIG. 2 (a)) for switching the switches 20 and 25 by the pulse generation circuit 42 is created,
The recording / reproducing magnetic heads 16a, 16b or 21a, 21b are switched to make the intermittent RF signals reproduced by the respective heads continuous RF signals, and the buffer amplifier 27 on the stator side via the windings 10b, 10a of the rotary transformer 8 . The reproduced RF signal transmitted to the buffer amplifier and amplified by the buffer amplifier is output from the terminal 28.
At this time, the recording / reproducing magnetic heads 16a, 16b or 21a, 21b are switched by the standard / long-time mode selection pulse (see FIG. 2 (c)).
If there is a pulse at this timing, the recording / reproducing magnetic heads 16a, 16
If b is selected and there is no pulse at the position, the long time mode is selected and the recording / reproducing magnetic heads 21a and 21b are selected.

At the time of recording, a pulse (Fig. 2 (b)) is input to the erase timing pulse input terminal 43, and the same as at the time of reproduction.
When the RF switching pulse and the selection signal of the recording / playback mode and the standard / long-time mode are input to the terminals 33, 34 and 35, respectively, the switch 38 is turned on and off by the pulse output from the control signal pulse generation circuit 36, The modulated wave of the signal (FIG. 2 (e)) is transmitted to the windings 11b and 11c via the winding 11a of the rotary transformer 8 . The signal is a detection circuit 41
After detection at, input to the control signal pulse generation circuit 42, according to the RF switching pulse and mode signal added on the stationary side, the changeover switch 17a, 17b, 22a, 22b, 20, 25, 26a on the rotating side,
The pulse and RF switching pulse required for switching 26b, 31a, 32a are created. The signal is also supplied to the rotation erasing head 40, but the rotation erasing head 40 is in contact with the magnetic tape only during the period of the signal 104 in FIG. 2 (e), and the erasing operation is performed only during the period. .

In FIG. 3, 8a 'and 8b' are grooves provided to prevent crosstalk between windings and are formed deeper than the grooves of each winding.

(G) Effect of the Invention With the configuration of the present invention, recording / reproduction can be performed without deterioration in image quality and without malfunction of the control circuit, and the number of winding grooves in the rotary transformer can be reduced, so that the size of the rotary transformer can be reduced. is there.

[Brief description of drawings]

FIG. 1 is a specific circuit block diagram of the present invention, FIG. 2 is a timing diagram of control signals and a waveform diagram of a signal transmitted by a rotary transformer, and FIG. 3 is a sectional view of a rotary transformer of the present invention. FIG. 4 is a sectional view of a conventional rotary transformer. 8 ... Rotary transformer, 11b ... Control signal modulated wave transmission winding, 11c ... Erase signal transmission winding, 16,21 ... Rotary magnetic head, 36 ... Control signal pulse generation circuit, 37 ... …
Oscillator, 41 …… Detection circuit, 42 …… Demodulation / control signal pulse generation circuit.

Claims (3)

[Claims] 1. A rotary cylinder is provided with a plurality of magnetic heads, a recording and / or reproducing circuit, a circuit block such as a control circuit for controlling the recording and / or reproducing circuit, and a signal and a signal via a rotary transformer. In a rotary magnetic head type magnetic recording / reproducing apparatus for transmitting electric power, the first and second winding grooves on the rotary side of the rotary transformer are provided.
Control signal pulse generation means for time-divisionally transmitting a plurality of different signals to the stationary side of the rotary transformer, and detection and demodulation processing of the control signal on the rotating side of the rotary transformer. And transmitting the plurality of types of signals to the first winding in a time division manner, and selectively transmitting a predetermined signal to the second winding according to the control signal. And a magnetic recording / reproducing apparatus. 2. The magnetic recording / reproducing apparatus according to claim 1, wherein the second winding is an erase signal transmitting winding, and the predetermined signal is an erase signal. 3. The magnetic recording / reproducing apparatus according to claim 1, wherein the plurality of types of signals are an RF switching pulse, a recording / reproducing switching signal, and a standard / long-time mode switching signal.