JPS6262403A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain a magnetic recording with a recording current fitted to the characteristic of a magnetic tape and to obtain a reproducing image of high quality by making very the recording current automatically corresponding to the kinds of magnetic tapes in a magnetic recording and reproducing device. CONSTITUTION:A rotating head 3 and a recording circuit 1 is coupled by a switching circuit 10, and a non-modulated carrier wave is recorded on an erased track 12 setting a considerable low recording current as an initial value. And the rotating head 3 and a reproducing circuit 2 are coupled by the switching circuit 10 and the non-modulated carrier wave is reproduced, detecting a reproduced voltage at that time by a reproducing voltage detecting circuit 9. Based upon the value of a detected reproducing voltage, a current control is performed at a recoding current control circuit 6 according to an optimum recoding current deciding circuit 8, deciding the next recording current, and an erasing, a recording and a reproducing are performed repeatedly in the travelling/terminating state of the magnetic tape. The decision of the optimum recording current fitted to the kind of the magnetic tape causes the coupling of the rotating head 3 with the recording circuit 1, the travelling of the magnetic tape and the recording of a video signal by the optimum recording current.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording and reproducing apparatus that can perform recording and reproducing suitable for the tape characteristics of a magnetic tape.

[Conventional technology]

FIG. 10 shows, for example, a conventional magnetic recording and reproducing apparatus, in which (1) is a recording circuit, (2) is a reproducing circuit, (3) is a rotating drum, and (4) is a rotating drum.

A conventional magnetic recording and reproducing device records a video signal on a magnetic tape with a rotating head (3) of a rotating drum (4) using a recording current fixed by a recording circuit (1), and then records the video signal on a magnetic tape by a reproducing circuit (2). It was being played by.

[Problem that the invention seeks to solve]

Conventional magnetic recording and reproducing devices have the disadvantage that since the recording current is fixed as mentioned above, only magnetic tapes with the same recording characteristics can be used, so magnetic tapes with improved recording characteristics are used. However, there was a problem in that the recording current had to be adjusted manually each time.

This invention was made to solve the above-mentioned problems, and its purpose is to provide a magnetic recording and reproducing device that can automatically record using a recording current that matches the recording current characteristics of the magnetic tape. It is something to do.

[Means for solving problems]

The magnetic recording and reproducing apparatus according to the present invention records data on erased tracks of a magnetic tape with a predetermined recording current, and when determining the reproduction voltage obtained by reproducing the recorded tracks, the recording current is sequentially changed. The optimum recording current that provides the maximum reproduction voltage is determined by changing the current.

[For production]

In this invention, by detecting the maximum value of the reproduction voltage, a recording current most suitable for the characteristics of the magnetic tape is determined, and magnetic recording is performed using this recording current.

[Embodiments of the invention]

FIG. 1 is an overall configuration diagram of an embodiment of a magnetic recording/reproducing apparatus according to the present invention. This embodiment includes an erasing circuit (5), a recording circuit (1), a reproducing circuit (
2), a switching circuit α0) for switching these circuits in synchronization with the pulses of the head rotation phase detector (7), and a recording current control circuit (6) for controlling the recording current of the recording circuit (1), Based on the reproduction voltage from the reproduction circuit (2), an optimum recording current determining circuit (8) determines a recording current suitable for the characteristics of the magnetic tape.

Next, the operation of the above embodiment will be explained with reference to FIGS. 1 to 4. FIG. 2 is an explanatory diagram of the operation of the rotating head, and the third
The figure is an explanatory diagram of magnetic tracks recorded on a magnetic tape. FIG. 4 is a flowchart showing an optimum recording current determining program stored in a control memory when the optimum recording current determining circuit of FIG. 1 is operated by, for example, a microcomputer.

First, when you press the record button on the magnetic recording/reproducing device, the magnetic tape (Qt) is transferred to the rotating drum (4) while the magnetic tape is not running.
), and the rotary head (3) slides helically on the magnetic tape (11). This state is shown in FIG. One rotary head (3) contacts the magnetic tape (11) at point A, passes through point B, reaches point 0, and leaves the magnetic tape θ1). For one rotary head (3), a magnetic track is drawn as shown in FIG. Therefore, the rotating head (3) and the erasing circuit (5) are connected by the switching circuit (101), and the magnetic track (12) shown in Fig. 3 is erased.The erasing method at this time is AC erasing, and the waveform It is shown in Fig. 5. At this time, the amplitude of the AC waveform is decreased every rotation of the drum, and AC cancellation is performed over a plurality of rotations.

This is because in a normal VTR, the signal from the rotary head (3) is transmitted to a signal processing circuit (not shown) through a rotary transformer (+3) as shown in FIG.

FIG. 8 shows a cross section of the rotary transformer (+3). There is a winding (15) in the concentric groove of the ferrite core, through which the signal is transmitted.Therefore, the erasure signal is performed using the alternating current signal that can be transmitted through this transformer in the above method. Next, the rotating head (3) and the recording circuit (1) are coupled by the switching circuit (QO) to record unmodulated carriers on the track (12) erased above with a sufficiently low R current as an initial value. Then, the switching circuit 00) connects the rotating head (3) and the reproducing circuit (2).
are combined to reproduce the unmodulated carrier, and the reproduced voltage at that time is detected by a reproduced voltage detection circuit (9). Based on the detected reproduction voltage value, the optimum recording current determining circuit (8)
Accordingly, the recording current control circuit (6) performs current control to determine the next recording current, and the above-described erasing, recording, and reproduction are repeated with the magnetic tape stopped running. This series of operating means is performed according to the flowchart of the optimum recording current determining circuit shown in FIG. In other words, the recording current is changed from the initial value I by △■
The recording current is increased in increments of , and the above operation is continued to set the recording current at the time when the reproduction voltage is the highest as the optimum value. This is because the characteristics of magnetic recording have a curve as shown in FIG. 6, and there is a point (18) where the reproduction voltage is highest, and the recording current at this point is set as the optimum recording current.

Once the optimum recording current suitable for the type of magnetic tape is determined by the above procedure, the rotating head (3) is coupled to the recording circuit (1), the magnetic tape is run, and the video signal is output at the optimum recording current. recorded.

Therefore, it is possible to perform recording and reproduction that fully adapts to the characteristics of the type of magnetic tape.

In the above embodiment, the track erasing method was AC erasing, but instead of the rotating transformer (+3), a slip ring 07) and a sliding plate (18) shown in Fig. 9 were used to erase the rotating head (3). In the method of transmitting output, DC cancellation may be performed, and in that case, a certain DC voltage may be applied.

Further, in the above embodiment, erasing, recording, and reproducing are repeated, but after performing erasing first, only recording and reproducing may be repeated.

〔Effect of the invention〕

As described above, according to the present invention, the magnetic recording/reproducing device is configured to automatically vary the recording current depending on the type of magnetic tape, so magnetic recording can be performed with a recording current that matches the characteristics of the magnetic tape, and high performance is achieved. This has the effect of providing high-quality reproduced images.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a magnetic recording/reproducing apparatus according to an embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams showing the relationship between a rotating head and a magnetic tape, and FIG. 4 is a diagram for determining the optimum recording current. Flowchart 1. FIG. 5 is an explanatory diagram showing the AC erasing method, FIG. 6 is an explanatory diagram showing the relationship between reproduction voltage and recording current,
FIG. 7 and FIG. 8 are explanatory diagrams of the rotary transformer, and FIG. 9 is an explanatory diagram showing a DC cancellation method. Further, FIG. 10 is a configuration diagram showing a conventional magnetic recording/reproducing device. In the figure, (1) is a recording circuit, (2) is a reproduction circuit, (
3) is a rotating head, (4) is a rotating drum, (5) is an erasing circuit, (6) is a current control circuit, (7) is a rotational phase detector, (8) is an optimum recording current determining circuit, ( 9) is a reproduction voltage detection circuit, and a[ is a switching circuit. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (3)

[Claims] (1) A recording current control circuit that sets the recording current of the signal recorded on the magnetic tape, a reproduction voltage detection circuit that detects the reproduction voltage of the recorded signal using the recording current, and a circuit that changes the recording current. A magnetic recording/reproducing apparatus comprising: an optimum recording current determining circuit that causes the recording current control circuit to set a recording current corresponding to a maximum reproduction voltage among the reproduction voltages obtained. (2) While the magnetic tape is wound spirally around a rotating drum in a stationary state, the rotary head of the rotating drum is used to repeatedly record and play back on a predetermined track of the magnetic tape, and detect the maximum playback voltage. A magnetic recording/reproducing device according to Claim 1. (3) A magnetic recording and reproducing apparatus according to claim 2, wherein the predetermined track of the magnetic tape is erased using a rotary head of a rotary drum before recording and reproducing the predetermined track.