JPS6112183A - Magnetic reproducing device - Google Patents

Abstract

PURPOSE:To correct a time axis error caused by the deviation of a reproducing magnetic head to a recording track by using the displacement of a reproducing magnetic head to correct the time axis error. CONSTITUTION:The displacement of the reproducing magnetic head 12 controlled by an automatic tracking circuit comprising an amplifier/demodulator 15 for a reproducing signal, electrostriction element control circuit 20, drive circuit 17 and an electrostriction element 13 is detected by a displacement detection sensor 14. The displacement detected in such a way is fed to a clock circuit 19, a write clock subject to phase modulation is generated and fed to a write address counter 23. A read address counter 24 designates an address of the memory 21 in synchronizing with a clock of a prescribed period fed via a terminal A to read the stored digital value. The read signal is subject to D/A conversion 22 and the time axis error due to the deviation to the recording track of the reproducing magnetic head included in the reproducing signal is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a so-called helical scan type VTR in which video signals are recorded and reproduced on a magnetic tape by a rotating magnetic head having an azimuth angle. The present invention relates to a magnetic reproducing device that can automatically correct deviations in the scanning locus with respect to the recording trunk.

Conventional configuration and its problems In a so-called helical scan type VTR in which video signals are recorded on a magnetic tape by a rotating magnetic head, the deviation of the reproducing magnetic head from the recording track is detected during reproduction, and the reproducing magnetic head is moved electrically. By installing it on a mechanical transducer and making it movable in a direction that intersects the recording track, it automatically corrects the scanning trajectory of the reproducing magnetic head.
The so-called auto-tracking method is well known in the art industry; for example, see Journal of the Television Society 197.
8, Vol. 32, No. 10, pages 839 to 840 are introduced in detail.

However, as shown in FIG. 1, track 1 recorded on magnetic tape 3 using a magnetic head with an azimuth angle in order to prevent effects between adjacent tracks can be recorded using a reproducing magnetic head 4 with a similar azimuth angle. When attempting to scan, the misalignment of the reproducing magnetic head 7 with respect to the recording trunk 6 results in an error 6 in the time axis of the reproduced signal, as shown in FIG. 2a. Therefore, as the head moves, the time axis error for a 1° trajectory of the center point of the head is as shown by reference numeral 11 in FIG. ).

In Fig. 1, 2 is the position where the FM signal corresponding to the horizontal synchronization signal in the video signal is recorded, and the actual number in one field period is 262 to 3, but for the sake of simplicity, Figure 2 shows a part of the recording track in Figure 1 enlarged for explanation, including the reproducing magnetic head, and 8, like 2, corresponds to the horizontal synchronization signal in the video signal. It shows the position where the corresponding FM signal is recorded.

OBJECTS OF THE INVENTION The present invention provides a magnetic reproducing apparatus that corrects time axis errors caused by relative positional deviation of a reproducing magnetic head with respect to a recording track.

Constituent Structure of the Invention Means for reproducing a signal recorded on a magnetic recording medium by a magnetic head having an azimuth angle, means for displacing the reproducing magnetic head having an azimuth angle in a direction crossing a recording track during reproduction, and a recording track. The apparatus includes means for correcting the relative positional relationship of the reproducing magnetic head with respect to the reproducing magnetic head, and means for correcting a time axis error of the reproduced signal, and during reproduction,
The time axis error of the reproduction signal caused by the movement of the reproduction magnetic head is corrected by the time axis correction means using the amount of displacement of the reproduction magnetic head.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to FIG. Third
In the figure, reference numeral 12 denotes a rotating magnetic head, which is attached to an electrostrictive element 13 together with a displacement detection sensor 14. 1
5 is an amplifier/demodulator for amplifying and demodulating the reproduction output of the rotating magnetic head 12; 18 is an A/D converter for converting the amplified and demodulated reproduction signal into a digital value; and 21 is the converted digital value. 22 is memory 2
A D/A converter for converting the digital signal from 1 into an analog signal, 16 a sensor amplifier for amplifying the output signal of the displacement detection sensor 14, and 19 the amplified output of the displacement detection sensor 14. 2o is an electrostrictive element control circuit for controlling the electrostrictive element 13 to correct the scanning locus of the reproducing magnetic head 12; 17 is the electrostrictive element 13;
23 is a write address counter for the memory 21; 23 is a write address counter for the memory 21;
Similarly, 24 is a read address counter to the memory 10.

The electrostrictive element 13 is constructed by, for example, bonding two layers of a plate-like body made of a ferroelectric material, fixing one end thereof, and utilizing the expansion and contraction of the plate-like body due to the piezoelectric effect (electrostrictive phenomenon) of the dielectric material. ,
This is an electro-mechanical conversion element that can obtain bending displacement at its free end. Further, the electrostrictive element control circuit 20 controls the electrostrictive element 13 in order to realize automatic tracking as described in detail on pages 839 to 840 of the Journal of the Television Society of Japan 197B=, Vol. 32, No. 10, for example. This is a control circuit.

Next, the operation of this embodiment will be explained. Amplifier/demodulator for reproduced signal 15. Electrostrictive element control circuit 20° drive circuit 17
．． The amount of displacement of the reproducing magnetic head 12 controlled by the automatic tracking circuit constituted by the electrostrictive element 13 is detected by the displacement amount detection sensor 14, amplified by the sensor amplifier 6, and then sent to the clock generation circuit 19. Supplied. This clock generation circuit 19 generates a write clock phase-modulated by the output of the displacement detection sensor 14 using, for example, a voltage controlled oscillator (not shown), and supplies it to the write address counter 23.

In the write address counter 23, the clock generation circuit 1
The write address of the memory 21 is controlled by the write clock supplied from 9. The read address counter 24 specifies an address in the memory 21 in synchronization with a constant periodic clock applied from the outside via the terminal A, and reads out the stored digital value. This read signal is converted from a digital value to an analog signal by the D/A converter 11, and the time axis error caused by the deviation of the reproducing magnetic head 1 with respect to the recording trunk, which was included in the reproduced signal, is corrected. be done.

In the embodiment shown in FIG. 3, the reproducing magnetic head 1
A displacement detection sensor 1 is used as a means for detecting the displacement amount of 2.
4 is used, however, as the type of sensor, an optical displacement sensor, a strain sensor that detects the amount of strain of an electrostrictive element, and a mass-produced displacement sensor of the reproducing magnetic head 12, etc. can be used.

In addition, in Fig. 3, a magnetic head for reproduction for one channel is used for simplicity, but by providing a circuit for selecting the magnetic head during reproduction, a reproduction device having a magnetic head for reproduction for two channels can be used. A similar effect can be obtained with respect to - Effects of the Invention As is clear from the above description, the present invention provides a means for recording signals on a magnetic recording medium using a magnetic head having an azimuth angle, and a means for recording a signal on a magnetic recording medium using a magnetic head having an azimuth angle, and a means for recording a signal on a magnetic recording medium by moving a reproducing magnetic head having an azimuth angle to a recording track during reproduction. A control means for correcting the relative positional relationship of the reproducing magnetic head with respect to the recording track; and a means for correcting a time axis error of the reproducing signal; By using this method to correct the time axis error, it is possible to correct the time axis error caused by the misalignment of the reproducing magnetic head with respect to the recording trunk.

[Brief explanation of the drawing]

Figure 1 is a conceptual diagram of a track recorded on a magnetic tape by a magnetic head with an azimuth angle.
FIG. 3 is an enlarged view of a part of the track in FIG. 1 is a block diagram of a magnetic reproducing device according to an example; FIG. 12... Magnetic head for reproduction, 13...
Electrostrictive element, 14...Displacement detection sensor, 15...
...Amplifier/demodulator, 16... Sensor amplifier, 17... Electrostrictive element drive circuit, 18...
...A/D converter, 19...Write clock generation circuit, 20...Electrostrictive element control circuit, 21...
...Memory, 22...D/A converter, 23.
...Write address counter, 24...Read address counter. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
figure

Claims (1)

[Claims] means for reproducing a signal recorded on a magnetic recording medium by a magnetic head having an azimuth angle; means for displacing the reproducing magnetic head having an azimuth angle in a direction crossing the recording track; The control means corrects the relative positional relationship by controlling the displacement means, and the means corrects the time axis error of the reproduced signal, the time axis error of the reproduced signal caused by the movement of the reproduction magnetic head during reproduction. A magnetic reproducing device characterized in that the error is corrected by the time axis error correcting means.