JPH052701A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent the output deterioration of a HiFi due to a temperature in a deep layer recording system, and to prevent the generation of a noise by decreasing the recording currents of a video signal running through the recording head according to the increase of the temperature afterwards. CONSTITUTION:A video signal is controlled so that a level can be constant by an AGC 1, high-pass emphasized by a pre-emphasis 2, and FM-modulated by an FM modulator 3. Next, it is temperature-compensated by a temperature compensator 4, and recorded through a recording amplifier 5 and a magnetic head 6 in a magnetic tape. Then, the recording currents of the video signal running through the recording head are decreased according to the increase of the temperature afterwards.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deep recording type VT.
The present invention relates to a magnetic recording / reproducing apparatus adapted to improve the temperature characteristic of a deep recording signal in R.

[0002]

2. Description of the Related Art A VHS type HiFi-VTR is an FM
First, the modulated HiFi sound is written on the magnetic tape by the head for the HiFi sound, and then the video signal FM-modulated by the video head (there is a case where the color signal converted into the low frequency is also superimposed). A so-called deep recording method is used in which data is overwritten.

FIG. 2 shows a deep layer HiFi recording system VHS-VT.
The frequency distribution figure of R is shown. Video luminance signal is 3.4MHz
FM is modulated to 4.4MHz, and the sideband spreads up and down. The video color signal is low-frequency converted from 3.5 MHz to 629 KHz and superimposed on the luminance signal. Also HiF
The i audio signal is FM-modulated centered on the L channel at 1.3 MHz and centered on the R channel at 1.7 MHz and recorded.

As shown in FIG. 3, these signals are transmitted on the magnetic tape 7 and the HiFi track 9 and the video track 8 on the HiFi track 9.
Are repeatedly recorded, and at the time of reproduction, they are reproduced by the respective recording heads. Since the HiFi sound recorded first is partially erased by the video signal recorded later, the reproduction output is significantly reduced compared to when the video signal is not recorded, but the azimuth angle is HiFi ± 30 °, and the video ± 6 °
In addition, since the head cap width can be individually and optimally selected, it is possible to significantly reduce the interference with each other as compared with the case where the frequency is divided into a single head for recording.

[0005]

[Problems to be Solved by the Invention] However, HiF
Since the output of the i audio signal is significantly reduced by the video signal, the output cannot be sufficiently obtained and noise is likely to occur particularly during long time recording with a narrow track width such as the triple mode. Further, since the recording capability of the magnetic head on the tape is lowered due to the temperature, when the temperature is high, the output of the HiFi voice is further lowered, and there is a problem that noise is likely to occur.

The present invention has been made to solve the above problems, and an object thereof is to obtain a magnetic recording / reproducing apparatus which does not reduce the output of a recording signal in a deep layer even when the temperature rises. To do.

[0007]

A magnetic recording / reproducing apparatus according to the present invention is a magnetic recording / reproducing apparatus in which different magnetic heads are used to record twice at the same location on a magnetic tape. It is characterized in that the recording current of the video signal is reduced as the temperature rises.

[0008]

Since the recording current of the video to be recorded later is reduced according to the rise in temperature, it is possible to compensate for the HiFi audio reproduction level which decreases due to temperature and suppress noise.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a block diagram of a magnetic recording / reproducing apparatus according to an embodiment of the present invention. The video signal is controlled by the AGS 1 so that the level becomes constant, is high-frequency emphasized by the pre-emphasis 2, and is FM-modulated 3.

Thereafter, the temperature compensation 4 according to the present invention is performed,
It is amplified by the recording amplifier 5 and a recording current is passed through the magnetic head 6 to record on the magnetic tape. As shown in FIG. 4, the temperature compensation characteristic 4 of the recording current is as shown in FIG.
The recording current is set to decrease.

In general, when the temperature rises, the output of the deep HiFi signal decreases more than the output of the surface video signal. Further, a slight change in the recording current in the surface layer causes a large change in the output level in the deep layer, but it does not affect the output of the video signal itself in the surface layer.

Therefore, if the recording current of the video signal on the surface layer is slightly reduced according to the temperature rise, the effect of compensating the deep layer output while suppressing the influence on the video signal to a minimum is very large.

In the embodiment, the deep recording in the VHS HiFi system has been described as an example, but the same can be applied to any magnetic recording system in which overwriting is performed by two different types of magnetic heads.

[0014]

As described above, according to the present invention, a simple temperature compensating circuit for decreasing the recording current of a video signal in response to the increase in temperature of the recording current supplied to the head for recording later is provided. By the addition, it is possible to prevent the output of the HiFi voice from being lowered due to the temperature of the deep recording system and prevent the generation of noise.

[Brief description of drawings]

FIG. 1 is a block diagram of a magnetic recording / reproducing apparatus according to the present invention.

FIG. 2 is a frequency distribution diagram of a deep HiFi recording system VHS-VTR.

FIG. 3 is a tape pattern diagram of a deep recording HiFi recording system VHS-VTR.

FIG. 4 is a temperature compensation characteristic diagram of a recording current in the present invention.

[Explanation of Codes] 1 AGC 2 Pre-emphasis 3 FM Modulation 4 Temperature Compensation 5 Recording Amplifier 6 Magnetic Head 7 Magnetic Tape 8 Video Track 9 HiFi Track

Claims (1)

Claim: What is claimed is: 1. In a magnetic recording / reproducing apparatus for recording twice on the same location of a magnetic tape by different magnetic heads, the temperature of a recording current applied to a head for recording later rises. Accordingly, the magnetic recording / reproducing apparatus is characterized in that the recording current of the video signal is reduced.