JPH05120765A - Tracking control circuit for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To provide the tracking control circuit of a magnetic recording and reproducing device which discriminates a frequency band where information is recorded and executes tracking adjustment based on a signal only in the frequency band. CONSTITUTION:When a FM signal outputted from an amplifier 3 is the signal in a high frequency band, the signal of this band passes through only the high- band pass filter 14 of a FM band discrimination circuit 10, then a signal is outputted from a detection part 16. The contact of a switch 17 is connected to a high-band pass filter 12 side by the output of the signal. Consequently, only the signal passing through the high-band pass filter 12 in the band is inputted to a detection part 5 and the tracking adjustment is executed base on only the signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking control circuit of a magnetic recording / reproducing apparatus used in video equipment such as video cameras and VTRs.

[0002]

2. Description of the Related Art Video devices such as video cameras and VTRs that use magnetic tapes are widely used. In such a video device, sound is recorded as information on a magnetic tape together with an image, but at the time of reproduction,
It is necessary to perform tracking control so that the head accurately traces directly above the track during recording. This tracking control is based on that recorded information,
It is performed by a circuit as shown in FIG. The information recorded on the magnetic tape 1 is taken out as a minute FM signal by the head 2 tracing the tape 1. The minute FM signal is amplified by the amplifier 3 and then demodulated to be a video signal. The FM signal after the amplification is passed through the high-pass filter 4 and the detection unit 5
Entered in. In this high-pass filter 4, the color signal recorded by the low-frequency conversion contained in this minute FM signal is removed. The detector 5 converts the input FM signal and outputs a DC voltage corresponding to the signal level. This DC voltage is output to the control microcomputer 6, and the control microcomputer 6 performs tracking adjustment by calculating the tracking position so that this DC voltage maintains the maximum level (optimum tracking state).

[0003]

However, in such a conventional tracking control circuit of the magnetic recording / reproducing apparatus, the tracking adjustment is performed based on the signal inputted through the high pass filter 4. Therefore, it is not affected by the crosstalk of low frequency band signals such as color signals and audio signals, but on the other hand, the effects of high frequency band signals such as high frequency noise and oscillation are There is a problem that the smaller the recording level, the greater the influence, which may cause a tracking malfunction.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and discriminates a frequency band in which information is recorded, and performs tracking adjustment based on a signal in that frequency band only. It is an object of the present invention to provide a tracking control circuit of a magnetic recording / reproducing apparatus that performs

[0005]

In order to achieve the above object, the present invention is based on a discriminating means for discriminating a recording frequency band of information recorded on a magnetic recording medium, and a discrimination result of the discriminating means. The present invention is characterized by having a selection input means for selectively inputting information of only the discriminated recording frequency band and a tracking adjustment means for adjusting tracking based on the information inputted via the selection input means.

[0006]

According to the tracking control circuit of the magnetic recording / reproducing apparatus of the present invention constructed as described above, the discriminating means discriminates which recording frequency band the information recorded on the magnetic recording medium belongs to. It This determination is specifically made based on the carrier of the FM signal from the head. The selection input means selectively inputs information existing in the frequency band in which the information is recorded, based on the discrimination result by the discrimination means. The tracking adjustment means is
The tracking is adjusted based on the information selected by the selection input means. Therefore, since the tracking adjustment can be performed only based on the information truly required for tracking, accurate tracking can always be realized.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a main part of a tracking control circuit of a magnetic recording / reproducing apparatus according to the present invention. In the same manner as shown in FIG. 2, the minute FM signal output from the head is amplified by the amplifier 3 and then demodulated to be a video signal. On the other hand, the FM signal after the amplification is input to the FM band determination circuit 10, the low band pass filter 11 and the high band pass filter 12, respectively. FM
The band discriminating circuit 10 includes a low bandpass filter 13, a high bandpass filter 14, and detectors 15 and 16 connected to these, respectively. The low band pass filters 11 and 13 are filters that pass the information recorded in the low frequency band, and the high band pass filters 12 and 14 are the filters that pass the information recorded in the high frequency band. For example, the system of the discrimination circuit 10 is B. P. It uses F,
In the case of the VHS system, the carrier is 3.4 in the low band.
In the case of super VHS, the carrier is 5.4 MHz in the high band.

Therefore, the pass band of the low band pass filter 11 is set to 3.4 to 4.4 MHz, and that of the high band pass filter 12 is set to 5.4 to 7 MHz. On the other hand, the low band pass filter 13
The band of the high band pass filter 14 is 3.4 MHz.
It is set to 5.4 MHz respectively. The detection unit 15 uses the low band filter 13 to obtain 3.4 MHz.
The signal is output when the carrier of is passed. Detector 1
Reference numeral 6 outputs a signal when a 5.4 MHz carrier passes through the high band filter 14. Since the FM band discriminating circuit 10 operates in this manner, it functions as a discriminating means for discriminating in which band the information is recorded. When a signal is output from the detection unit 15, the contact of the switch 17 is connected to the low bandpass filter 11 side, and when a signal is output from the detection unit 16, the switch 1
The contacts 7 are connected to the high band pass filter 12 side as shown. Therefore, the switch 17 functions as a selection input means.

The switch detector 5 converts the input FM signal and outputs a DC voltage corresponding to the signal level. This DC voltage is output to the control microcomputer 6, and the control microcomputer 6 performs tracking adjustment by calculating the tracking position so that this DC voltage maintains the maximum level (optimum tracking state). The detection unit 5 and the control microcomputer 6 function as tracking adjustment means.

The control circuit having the above-mentioned structure functions as follows. When the FM signal output from the amplifier 3 is a super VHS FM signal, the FM band determination circuit 10 operates from 5.4 MHz to 7 MHz.
A signal in a certain band will be detected. That is, since the signal in this band passes only the high band pass filter 14, the signal is output from the detection unit 16.
By the output of this signal, the contact of the switch 17 is connected to the high band pass filter 12 side as shown in the figure. Therefore, only the signal in the band of 5.4 MHz to 7 MHz that has passed through the high band pass filter 12 is input to the detection unit 5, and the tracking adjustment is performed based only on this signal. Therefore, there is no possibility of adversely affecting the tracking adjustment due to crosstalk noise in other bands.

In this embodiment, the configuration in which the signals in the two bands are selectively taken in has been exemplified, but the present invention is not limited to this, and the configuration in which the signals in three or more bands can be taken in is not limited to this. However, the present invention is applicable. The present invention, when the information of both bands is mixedly recorded on a magnetic tape capable of recording both the high band having a high recording frequency band and the low band having a low recording frequency band, the tracking adjustment of each band is performed. It is very useful in that it can be done automatically and accurately.

[0012]

As is apparent from the above description, according to the present invention, accurate tracking adjustment can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of a tracking control circuit of a magnetic recording / reproducing apparatus according to the present invention.

FIG. 2 is a block diagram showing a main part of a tracking control circuit of a conventional magnetic recording / reproducing apparatus.

[Explanation of symbols]

 3: Amplifier 5: Detection unit (tracking adjustment means) 6: Control microcomputer (tracking adjustment means) 10: FM band determination circuit (determination means) 11: Low band pass filter (selection input means) 12: High band pass filter (selection) Input means) 17: Switch (selection input means)

Claims (1)

[Claims] 1. A discriminating means for discriminating a recording frequency band of information recorded on a magnetic recording medium, and selectively inputting information only for the discriminated recording frequency band based on the discrimination result of the discriminating means. A tracking control circuit for a magnetic recording / reproducing apparatus, comprising: a selection input means; and a tracking adjustment means for adjusting tracking based on information input via the selection input means.