JPS63269302A - Signal fetching device - Google Patents

Abstract

PURPOSE:To perform the monitoring of a reproduction signal at the same time with a recording operation without making a device into a large size, by providing a head for reproduction only, an electric photo transfer means, an optical fiber cable, an incident light convergence means, and a photoelectric transfer means. CONSTITUTION:The reproduction signal is fetched from a magnetic recording medium by the head 14 for reproduction only rotating by interlocking with a rotary shaft 14, and an electrical signal is converted to an optical signal by the electric-photo transfer means 15, and the optical signal is transmitted to the incident light convergence means 19 by the optical fiber 16. And it is possible to take out the reproduction signal recorded on the magnetic recording medium to the outside by converging the optical signal on an optical axis which makes the same concentric circle as the rotary shaft 14 by deflecting the optical signal by the incident light convergence means 19 and converting convergence light that is the output of the incident light convergence means 19 to the electrical signal by the photoelectric transfer means 21. In such a way, it is possible to fetch the reproduction signal from a magnetic tape as performing the recording operation of an input signal on the magnetic tape, and to monitor the recording state of the signal, and to obtain a head with high sensitivity.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a magnetic recording and reproducing device for recording and reproducing signals on a magnetic recording medium using a magnetic head provided on a rotating drum mechanism such as a video tape recorder. The present invention relates to a signal extraction device used in equipment, etc.

[Conventional technology]

Conventionally, when recording signals such as video signals in a video tape recorder (hereinafter referred to as VTR) equipped with a rotating drum mechanism, for example, the recorded signal is processed into a predetermined signal, and then this signal is passed through a rotating transformer. The information is transmitted to the recording/reproducing head via the recording/reproducing head and recorded on a magnetic tape, which is a magnetic recording medium. On the other hand, when reproducing a signal, the signal recorded on the magnetic tape is converted into an electrical signal by the recording/reproducing head, and then transmitted from the rotating drum side to the fixed drum side through a rotating transformer, and converted into a predetermined reproduced signal. It is processed and sent to the monitor.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional magnetic recording and reproducing apparatus, since the recording signal and the reproduction signal are transmitted through the rotary transformer 5, basically, the signals recorded on the magnetic tape are extracted simultaneously during the recording operation. It is difficult to play it back. In other words, conventionally, professional VTRs have been equipped with a special rotating transformer to monitor the playback signal at the same time as the recording operation, but this structure requires a fairly large device, making it unsuitable for consumer use. It has the problem that.

Means for Solving Problem C] In order to solve the above problems, the signal extraction device of the present invention includes a read-only head that rotates in conjunction with a rotating shaft and extracts signals from a magnetic recording medium that is in sliding contact with it. , an electro-optical conversion means for converting an electrical signal outputted from the read-only head into an optical signal, an optical fiber cable for transmitting the optical signal output from the electro-optic conversion means to an incident light converging means, and an optical fiber cable concentric with the rotation axis. an incident light converging means for deflecting the optical signal transmitted by the optical fiber cable and converging it onto an optical axis concentric with the axis of the rotating shaft; and a converging means output from the incident light converging means. The structure includes photoelectric conversion means for converting light into an electrical signal.

[For production]

As mentioned above, a playback signal is extracted from a magnetic recording medium using a read-only head that rotates in conjunction with a rotating shaft, and this electric signal is converted into an optical signal by an electro-optical conversion means, and this optical signal is transmitted through an optical fiber cable. The incident light converging means deflects the optical signal to converge it on an optical axis concentric with the rotation axis, and the photoelectric conversion means converts the converged light output from the incident light converging means into an electrical signal. By converting, the reproduced signal recorded on the magnetic recording medium can be extracted to the outside.

[Embodiment 1] An embodiment of the present invention will be described below based on FIGS. 1 to 5.

A VTR, which is a magnetic recording and reproducing device, is shown in Figs. 5(a) and (b).
As shown in the figure, it has a rotating drum mechanism consisting of a fixed drum 7, a rotating drum 8, a rotating shaft 4, and the like. A rotary drum 8 is fixed to the rotary shaft 4, and head support members 6a, 6a for supporting a rotary transformer 5 and recording/reproducing heads 6, 6 connected to the rotary lance 5 are fixed to the rotary shaft 4. These members rotate with the rotation of 4. A magnetic tape 9, which is a magnetic recording medium, is in sliding contact with the fixed drum 7 and the rotating drum 8, and recording/reproducing heads 6, 6 provided at an angle of 180 degrees are in sliding contact with this magnetic tape 9. It is configured.

In addition, the VTR has a signal recording system that includes a recording signal processing section I that performs predetermined processing to perform appropriate recording on recording signals such as video signals; FM modulator 2 for FM modulating the signal, and F
A recording amplifier 3 is provided to amplify the output of the M modulator 2.

The recording amplifier 3 is connected to the rotary transformer 5 via a changeover switch 23 that switches between a recording operation and a reproduction operation. Further, the VTR includes a signal reproduction system including a reproduction amplifier 10 which is connected to the changeover switch 23 and amplifies reproduction signals from the recording and reproduction heads 6 obtained via the rotary transformer 5;・Reproduction equalizer 11 that appropriately switches the amplified reproduction signal corresponding to 6 and arranges it into a predetermined reproduction signal, and FM demodulator 1 that demodulates the FM reproduction signal output from the reproduction equalizer 11.
2, and a reproduction signal processing unit 13 that performs appropriate processing on the reproduction signal output from the FM demodulator 12 and sends it to a monitor.

On the other hand, the above-mentioned rotating drum mechanism is provided with a signal take-out device, and this signal take-out device includes a read-only head 14 that is in sliding contact with the magnetic tape 9 and rotates together with the rotating shaft 4, as shown in FIG. 14 are arranged at an angle of 180°, and these reproduction-only heads 14, 14 are respectively
It is connected to electro-optical converters 15, 15 that convert electrical signals into optical signals. The electro-optical converters 15, 15 are fixed to the rotating drum 8, and are provided close to the read-only heads 14, 14. Optical fiber cables 6 and 16, which serve as transmission media for optical signals output from the electro-optic converters 15 and 15, are connected to the electro-optic converter means 15, respectively, and these optical fiber cables 16 and 16 It is connected to an entrance-side plastic lens 17 housed concentrically with the rotating shaft 4 at the upper part of the inner part. By setting an appropriate length, the input side plastic lens 17 directs the optical signals transmitted from the optical fiber cables 16, 16 to the output end surface of the lower end surface, as shown in FIG. 2 or 3. It is designed to emit parallel light. That is, the refractive index on the optical axis 18 that coincides with the axis of the rotation axis 4 is n', the refractive index distribution constant is fX, and the distance from the light source to the incident end surface is 11.
The relational expression that holds true when the distance from the output end face to the focal point is β2 and the length of the plastic lens 17 on the input side is Zl, no l, (K 5iniZ, -cosfKZr, the input side plastic is set so that 1t=0. lens 1
By selecting the length Z of 7, parallel light can be obtained.

Further, an output-side plastic lens 19 is housed concentrically with the rotation shaft 4 at the lower end of the rotation shaft 4 below the input-side plastic lens 17 . By setting the output side plastic lens 19 to an appropriate length, as shown in FIG.
, to form a focal point 20 on the optical axis 18. Output side plastic lens 19
The distance 13 from the output end face to the focal point 20 can be determined by the following relational expression, assuming that the length of the output side plastic lens 19 is 22.

The distance between the two lens F-19 is determined in consideration of the insertion loss in the configuration of the system for obtaining parallel light as described above,
Judging from published values, even if it is set to 40 to 50 degrees, no increase in insertion loss occurs. Therefore, in consideration of this value, the output side plastic lens 19 is provided at the lower end of the rotating shaft 4, and the position of the input side plastic lens F is determined. Note that instead of the above-mentioned entrance side plastic lens 17 and exit side plastic lens 19, it is also possible to use, for example, a SELFOC lens (trade name) having the same function as these plastic lenses 17 and 19.

Further, at the above focal point 20 position below the output side plastic lens 19, the output side plastic lens 19
A photo-electrical converter 21 is provided which receives light emitted from the light source and converts it into an electrical signal. The arrangement position of the photoelectric converter 21 is not limited to the above-mentioned position, and may be between the output end face of the output side plastic lens 19 and the focal point 20.

The photoelectric converter 21 is fixed to the fixed drum 7, and is connected to the regenerative amplifier 10 that constitutes the signal reproducing system of the VTR.

In the above configuration, in the signal recording system, a recording signal such as a video signal is processed by the recording signal processing section 1, then subjected to FM modulation by the FM modulator 2, and amplified by the recording amplifier 3.
The signal is transmitted to the recording and reproducing heads 6, which also work with the rotary shaft 4, through a rotary transformer 5 that works with the rotary shaft 4, and is recorded as a magnetization pattern on the magnetic tape 9. In the signal reproducing system, the signals recorded on the magnetic tape 9 are converted into electrical signals by the recording/reproducing heads 6, 6, and then taken out.
It is transmitted from the rotating drum 8 side to the fixed drum 7 side through the rotating transformer 5. After being amplified to a specified voltage by a regenerative amplifier 10, it is demodulated by an FM demodulator 12 via a reproducing sake cup 11, and then processed into a predetermined reproduced signal by a reproduced signal processing section 13 and sent to a monitor. ing.

On the other hand, on the signal extraction device side, as the rotation shaft 4 rotates, the read-only heads 14, 14, the electro-optic converter 15
-15, the optical fiber cable 16, the input side plastic lens 17, and the output side plastic lens 19 are rotated.

Here, when the signal extraction device is operated, the signals recorded on the magnetic tape 9 are extracted as reproduction electric signals by each reproduction-only head 14. This playback signal is
It is converted into an optical signal by the electro-optic converter 15, 15, and transmitted to the incident side plastic lens 17 through each optical fiber cable 16, 16. Incident side plastic lens 1
The optical signal incident on the lens 7 is sent out as parallel light from the output side end face, and is incident on the output side plastic lens 19 . Then, from this exit side plastic lens 19 to the focal point 20
After being emitted so as to converge, the light enters the photo-electrical converter H21 and is converted into an electrical signal. Thereafter, this reproduced signal is input to the regenerative amplifier 10, subjected to predetermined processing in each section of the signal reproducing system, and then transmitted to the monitor.

The signal reproducing operation in the above signal extraction device is performed by the VTR.
Because it is independent from the original recording and playback operation,
It can be performed in parallel with the recording/reproducing operation.

In this embodiment, a configuration is shown in which one channel of reproduced signal is taken out, but the electro-optic converter 15 and the photo-electric converter 21 are provided according to the number of channels, and a step-in-death type optical fiber is used. By providing the , homographic, and both plastic lenses 17 and 19, multi-channel signal extraction can be performed.

[Embodiment 2] Another embodiment of the present invention will be described below based on FIG. 6. Incidentally, members having the same functions as those in the first embodiment are denoted by the same reference numerals, and their explanations will be omitted.

The signal extraction device according to this embodiment is provided with one plastic lens 22 in place of the entrance-side plastic lens 17 and the exit-side plastic lens 19 shown in FIG. Inside this plastic lens 22,
The incident light is appropriately deflected and travels while repeating the amplitude of a constant period.

The plastic lens 22 has a lower output end surface "
The length is set such that the optical signal emitted from the optical axis 18 forms a focal point 20 at an appropriate position on the optical axis 18. Therefore,
It has the same function as the structure consisting of the entrance side plastic lens 17 and the exit side plastic lens 19.

〔Effect of the invention〕

As described above, the signal extraction device of the present invention includes a read-only head that rotates in conjunction with a rotating shaft and extracts signals from a magnetic recording medium in sliding contact, and an electric signal output from the read-only head that converts it into an optical signal. an electro-optical conversion means for converting, an optical fiber cable for transmitting the optical signal output from the electro-optical conversion means to the incident light converging means, and provided concentrically with the rotation axis,
By deflecting the optical signal transmitted through the optical fiber cable,
This configuration includes an incident light converging means for converging onto an optical axis concentric with the axis of the rotating shaft, and a photoelectric conversion means for converting the convergent light output from the incident light converging means into an electrical signal.

Therefore, in a magnetic recording device such as a VTR equipped with this device, the playback signal can be extracted from the magnetic tape while recording the input signal onto the magnetic tape, without increasing the size of the device. Recording status can be monitored. Moreover, when designing a playback-only head, the band is generally limited by the inductance of the rotating transformer and the capacitance of the capacitor.
Since the structure of the present invention is not subject to such limitations, the inductance of the read-only head can be increased to the maximum, and a head with high sensitivity can be obtained. Therefore, effects such as high quality reproduction can be achieved.

[Brief explanation of drawings]

1 to 5 show one embodiment of the present invention, in which FIG. 1 is an explanatory diagram showing a signal extraction device according to the present invention, and FIG. 2 is an illustration of the input side plastic shown in FIG. An explanatory diagram of the lens, Fig. 3 is an explanatory diagram of another input side plastic lens, Fig. 4 is an explanatory diagram of the output side plastic lens shown in Fig. 1, and Fig. 5 (a) and (b) are respectively Schematic explanatory diagram and block diagram showing the main parts of a video tape recorder 1.
FIG. 6 is an explanatory diagram of a signal extraction device showing another embodiment of the present invention. 4 is a rotating shaft, 5 is a rotating transformer, 6 is a recording/reproducing head,
7 is a fixed drum, 8 is a rotating drum, 9 is a magnetic tape (magnetic recording medium), 14 is a playback-only disk, 15 is an electro-optic converter (electro-optical conversion means), 6 is an optical fiber cable, and 17 is an input side plug.・Tsukulens (incident light convergence means), 18 is a preemptive 9 is an output side plastic lens (incident light convergence), 20
is a focal point, 21 is a photo-electrical converter (optical π means), and 22 is a plastic lens (incident and means). Patent applicant Sharp Stock% formula%

Claims (1)

[Claims] 1. A read-only head that rotates in conjunction with a rotating shaft and extracts signals from a magnetic recording medium in sliding contact, an electro-optical conversion means that converts an electrical signal output from the read-only head into an optical signal, and an electro-optical conversion means An optical fiber cable that transmits the output optical signal to the incident light converging means, and an optical fiber cable that is provided concentrically with the rotation axis, deflects the optical signal transmitted by the optical fiber cable, and is concentric with the axis of the rotation axis. What is claimed is: 1. A signal extraction device comprising: an incident light converging means for converging incident light onto an optical axis; and a photoelectric conversion means for converting the convergent light output from the incident light converging means into an electrical signal.