JPH03108116A - Rotary head type recording and reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to VTR (video tape recorder), DAT
The present invention relates to a rotary head type recording and reproducing device such as a digital audio tape recorder (digital audio tape recorder).

[Prior art] In order to improve the SN ratio (signal to noise ratio) during playback,
It is known to incorporate a head amplifier in a rotating drum and to supply a driving voltage to the head amplifier via a slip ring. It is also conceivable to supply the drive voltage for the head amplifier via a rotary transformer dedicated to the power supply and a rectifier circuit.

[Problems to be Solved by the Invention] By the way, if the former slip ring is used, the slip ring must be attached to the rotating drum and a brush must be attached around the drum, so the drum size becomes large and the VTR In addition, if a rotary transformer dedicated to the power supply is used in the latter case, not only will the device become larger due to the provision of a rotary transformer dedicated to the power supply, but the AC power supply will have a negative effect on the recording and playback circuits. The problem arises that

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rotary head type recording/reproducing device that can easily obtain a driving voltage for a head amplifier in a rotary drum.

[Means for Solving the Problems] To achieve the above object, the present invention includes a rotating drum, a recording/reproducing head attached to the rotating drum, and a rotating side winding and a stationary side winding that are electromagnetically coupled to each other. a recording/reproducing rotary transformer having a recording signal processing circuit, a reproduction signal processing circuit, the recording signal processing circuit being connected to the fixed side winding during recording, and the reproduction signal processing circuit being connected to the fixed side winding during reproduction. a recording/reproducing switching circuit connected to the winding; a recording signal transmission circuit provided on the rotary drum side for connecting the rotating side winding to the recording/reproducing head during recording; and an amplifier. a reproduction signal transmission circuit provided on the rotating drum side for transmitting the output of the recording/reproducing head to the rotating side winding; and a reproduction signal transmission circuit connected to the rotating side winding and provided on the rotating drum side. A rectifying circuit, and a rechargeable power source connected to the rectifying circuit, provided on the rotating drum side, and connected to a power terminal of the amplifier of the reproduced signal transmission circuit. The present invention relates to a rotary head type recording/reproducing device.

Note that the present invention can also be applied to the case where a recording head and a reproducing head are provided instead of the recording/reproducing head.

Furthermore, a check means is provided to determine whether or not the storage battery needs to be charged, and a recording mode for charging can be set when necessary.

[Function] In the present invention, the recorded signal is used to charge a rechargeable power source such as a storage battery or a capacitor. Therefore,
It becomes possible to obtain the necessary force without using springs or dedicated rotary transformers.

[First Embodiment] Next, a VTR according to a first embodiment of the present invention will be described with reference to FIG.

The basic configuration of this VTR is the same as a VH3 type or Betamax type small VTR, and has an upper cylinder, or rotating drum 1, and a lower cylinder, or fixed drum 2. First and second heads 3.4, which are magnetic heads for both recording and reproducing purposes, are attached.

The first and second heads 3.4 are rotationally driven together with the rotating drum 1 by a motor (not shown). A magnetic tape (not shown) runs along the rotating drum 1;
Above this, a diagonal scanning track occurs.

The recording signal processing circuit 6 connected to the recording input terminal 5 is connected to the F
It includes an M modulation circuit, and outputs the FM modulated composite video signal of, for example, the NTSC system. The reproduced signal processing circuit 7 performs FM demodulation on the reproduced signal and outputs a composite video signal to the output terminal 8. The recording signal processing circuit 6 and the reproduction signal processing circuit 7 include a recording and reproduction switching circuit 9, first and second rotary transformers 10.11, and first and second rotary drum internal signal processing circuits 12.13. via which it is connected to the first and second heads 3.4.

The first and second rotary transformers 10.11 are known ones, and include fixed side windings 10a, lla provided on the fixed drum 2 side, and rotating drum ll11! It has rotating side windings 10b and llb provided in l, and fixed side winding 10a.
, lla and the rotating side windings 10b, 11b are electromagnetically coupled to each other.

Since the first and second rotating drum signal processing circuits 12 and 13 have the same configuration, only one is shown in detail and the other is shown in blocks.
2 has a recording signal transmission circuit and a reproduction signal transmission circuit between one terminal 14 of the rotating side winding 10b of the rotary transformer 1° and one terminal 15 of the first head 3. Note that the other terminal 16 of the rotating side winding 10b is connected to ground, and the other terminal 17 of the head 3 is also connected to ground.

The recording signal transmission circuit includes a first transistor 18 as a switch connected between the winding terminal 14 and the head terminal 15. In the reproduced signal transmission circuit, one input terminal is connected to one head terminal 15, the other input terminal is connected to the other head terminal 17, and the output terminal is connected to the winding terminal 1.
A head amplifier 19 is provided, which is an operational amplifier (differential amplifier) connected to 4.

20 is a transistor control circuit for controlling the transistor 18 to be turned on during recording and to turn off the transistor 18 during reproduction, and includes two capacitors 21 and 22;
It consists of two diodes 23 and 24. Note that one end of the capacitor 21 is connected to the winding terminal 14, a diode 23 is connected between this other end and the ground in a reverse bias direction, and the other end of the capacitor 21 is connected to the diode 24.
The capacitor 22 is connected between the base of the transistor 18 and ground.

25 supplies a driving voltage to the head amplifier 19 during reproduction;
This is an amplifier control circuit for cutting off the supply of drive voltage during recording, and includes a second transistor 26 and a diode 27.
, a capacitor 28, and a resistor 29. Note that the second transistor 26 is connected between one terminal 31 of the storage battery 30 provided according to the invention and the power supply terminal 32 of the head amplifier 19, and the diode 27 is connected between the winding terminal 1
A capacitor 28 and a resistor 29 are connected between the base of the transistor 26 and ground.

33 is a half-wave rectifier circuit provided according to the present invention, which includes a rectifying diode 34 connected between the winding terminal 14 and one terminal 31 of the storage battery 30, and a cathode of this diode 34 and a ground. and a smoothing capacitor 35 connected between them. In order to function as a power source for the head amplifier/device 19, the storage battery 30 has one terminal 31 connected to a power supply terminal 32 of the head amplifier 19 via a transistor 26, and the other terminal 36 connected to ground. has been done.

The operation will be explained below.

When the VTR is set to recording mode, the recording signal processing circuit 6
The FM''R tone circuit operates, and a recording signal consisting of a frequency signal is sent to the rotating drum 1fll via the rotary transformer 10.
transmitted to J. Rotating winding 1 of rotary transformer 10
The recording signal 0b is sent to the head 3 via the transistor 18.
A rectifier circuit 3 which is sent to the
3 converts the voltage into a DC voltage and sends it to the storage battery 30. Since the storage battery 30 has a relatively small capacity, this charging can be accomplished using the recording signal.

In addition, in this recording mode, the voltage of the rotary transformer 10 is clamped by a clamp circuit consisting of a capacitor 21 and a diode 23, which is connected to a diode 24.
A DC voltage twice as high as the positive peak voltage of the recording signal is obtained. As a result, the transistor 18 is turned on in the saturation region, and a recording signal is transmitted to the head 3. Further, in the recording mode, the recording signal is rectified by the diode 27 in the amplifier control circuit 25, the capacitor 28 is charged, the transistor 26 is controlled to be off, and the head amplifier 19 is in a non-driven state.

In the reproduction mode, since the supply of the recording signal is stopped, charging of the capacitor 28 in the amplifier control circuit 25 is also stopped, the charge of the capacitor 28 is discharged via the resistor 29, and the base potential of the transistor 26 becomes ground. As a result, the transistor 26 is turned on, the head amplifier 19 is driven by the storage battery 30, and the output obtained from the head 3 is amplified and sent to the rotary transformer 10. In this regeneration mode, the charge in the capacitor 22 flows to the ground through the base-emitter of the transistor 18 and the rotating winding 10b of the rotary transformer, and the transistor 18 is turned off within a short time. At this time, a reproduced output is generated from the head amplifier 19, but since it is approximately 1 mV, the diode 24 is kept in an OFF state and the capacitor 22 is not charged.

As described above, according to this embodiment, the power supply voltage for the head amplifier 19 in the rotary drum 1 can be supplied based on the storage battery 30 charged with the recording signal. Therefore, it is possible to improve the SN ratio while suppressing increase in size and cost.

[Second Embodiment] Next, a VTR according to a second embodiment shown in FIG. 2 will be described. However, parts in FIG. 2 that are common to those in FIG. 1 are designated by the same reference numerals and their explanations will be omitted. This VTR includes a check signal generating circuit 40, a head 41 for transmitting this signal to the heads 3 and 4, and a check signal generating circuit 40 connected to the reproduction output terminal 8, in order to check whether the storage battery 30 needs to be charged. It has a circuit 42 and a microcomputer 43 for controlling the check.

The magnetic tape 44 omitted in FIG. 1 is the cassette 4.
5 and wound around the rotating drum 1 in an Ω shape. A pair of reels 46 and 47 of the cassette 45 are rotated by a reel motor 48.

In addition, a pinch roller, a capstan, etc. are arranged as a tape running device on the running path of the magnetic tape 44. The plunger solenoid 49 controls the winding of the magnetic tape 44 around the rotating drum 1 .

In this device, when the power is turned on or when a battery check command is given to the microcomputer 43, the microcomputer 43 sets a playback mode for checking. In this check reproduction mode, the magnetic tape 44 is separated from the rotating drum 1. When the check signal generating circuit 40 is controlled by the microcomputer 43, a check signal consisting of a frequency signal is generated from the check signal generating circuit 40, and an alternating magnetic field for checking is generated from the head 41. Since the head 41 is arranged opposite to the path of the recording/reproducing head 3.4, it detects the check signal and sends the reproduction signal to the reproduction signal processing circuit 7 outside the rotating drum via the rotating drum side signal processing circuit 12.13. send to

The check circuit 42 consists of an integrating circuit that integrates the reproduced output, and a comparator that compares the output of this integrating circuit with a reference voltage to detect the presence or absence of the reproduced signal. If storage battery 3
0 is the predetermined voltage rotating drum side signal processing circuit 12.13
If the output voltage is supplied to the head amplifier, the level of the reproduction output voltage obtained at the reproduction output terminal 8 will be higher than the reference level,
The check circuit 42 notifies the microcomputer 43 of a signal indicating that the storage battery 30 is being charged. As a result, the microcomputer 43 immediately cancels the check playback mode and sets the normal recording or playback mode.

On the other hand, when the check circuit 42 detects that a reproduced signal higher than the reference level cannot be obtained, this is notified to the microcomputer 43 and also sent to the battery status display. If the playback output is below the reference level, it means that the voltage of the storage battery 30 has decreased, so the microcomputer 43 sets the charging recording mode and outputs the recording signal (F
M wave) to the rotating drum internal signal processing circuit 12.13,
Charge the storage battery 30. When a normal recording command is generated during this charging recording mode, the charging recording mode is canceled and the mode is shifted to the normal recording mode, and the storage battery 30 is charged in the normal recording mode. Furthermore, when a reproduction command is issued, the setting of the reproduction mode is suspended until the recording mode for charging ends, and the reproduction is started after the recording mode for charging ends for a predetermined time.

[Modifications] The present invention is not limited to the above-described embodiments, and, for example, the following modifications are possible.

(1) As shown in FIG. 3, a pair of recording magnetic heads 3
a, 4a, and a pair of reproducing magnetic heads 3b, 4b arranged so as to have an angular difference of approximately 90 degrees from these, and rotating drum side recording signal transmission circuits 12a, 1, respectively.
3a and rotating drum side reproduction signal transmission circuits 12b and 13b
are provided, and these are connected to rotary transformers 51, 52, 53.
The present invention can also be applied to the case where the rotary drum is connected to a recording circuit and a reproducing circuit outside the rotary drum via the rotary drum 54.

In this case, the voltage of the storage battery 30 charged based on the recording signal supplied to the recording heads 3a, 4a is applied to the reproduction signal transmission circuits 12b, 13b. In addition, in FIG. 3, the heads 3a and 4b are replaced with recording/reproducing heads,
The recording signal transmission circuits 12a and 13a can be replaced with recording and reproduction signal processing circuits.

(2) The storage battery 30 can be replaced with a capacitor, and the capacitor can be used as a chargeable power source.

(3) The frequency of the check signal sent from the check signal generation circuit 40 is changed in several steps, and the state of charge of the storage battery 30 is determined not only by changes in the voltage level of the reproduction output but also by changes in the frequency characteristics. In this case, the check circuit 42 may include a bandpass filter.

(4) The check signal generator 40 in FIG. 2 can be replaced by an erase signal generator.

(5) The present invention can also be applied to DAT.

(6) The transistor 18 can be replaced with another signal transmission element, signal transmission circuit, or switch element.

[Effects of the Invention] As is clear from the above, according to the present invention, a driving voltage can be applied to the amplifier on the rotating drum side with an extremely simple configuration. Therefore, the S/N ratio can be improved without compromising the miniaturization and cost reduction of the device.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a VTR according to a first embodiment of the present invention, FIG. 2 is a circuit diagram showing a VTR according to a second embodiment of the present invention, and FIG. 3 is a rotating drum and a circuit diagram of a modified VTR. FIG. 2 is a block diagram showing a head. 1... Rotating drum, 3... First head, 4...
Second head, 6... recording signal processing circuit, 7... reproduction signal processing circuit, 10.11... rotary transformer,
19... Head amplifier, 30... Storage battery, 33...
- Rectifier circuit.

Claims (1)

[Scope of Claims] [1] A recording/reproducing rotary transformer comprising: a rotating drum; a recording/reproducing head attached to the rotating drum; a rotating side winding and a stationary side winding that are electromagnetically coupled to each other; a signal processing circuit; a reproduction signal processing circuit; a recording/reproduction switching circuit that connects the recording signal processing circuit to the fixed winding during recording and connects the reproduction signal processing circuit to the fixed winding during reproduction; a recording signal transmission circuit provided on the rotating drum side for connecting the rotating side winding to the recording/reproducing head; a reproduction signal transmission circuit provided on the rotating drum side for transmission; a rectifier circuit connected to the rotating drum side and connected to the rotating drum side; A rotary head type recording/reproducing apparatus, comprising: a rechargeable power source provided on the rotary drum side and connected to a power supply terminal of the amplifier of the reproduced signal transmission circuit. [2] a rotating drum; a recording head attached to the rotating drum; a reproducing head attached to the rotating drum; and a head amplifier connected to the reproducing head and provided on the rotating drum side; a recording signal processing circuit; a reproduction signal processing circuit; a recording rotary transformer provided between the recording signal processing circuit and the recording head; and a recording rotary transformer provided between the head amplifier and the reproduction signal processing circuit. a rectifier circuit connected to the recording rotary transformer and provided on the rotary drum side; a rectifier circuit connected to the rectifier circuit so as to be charged by the output of the rectifier circuit; A rotary head type recording/reproducing device comprising: a rechargeable power source provided on the drum side and connected to a power source terminal of the head amplifier.