JPS63302684A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To eliminate noise on a reproduced picture at the time of switching by synchronously switching the output of a head with a horizontal scanning synchronizing signal at a timing which does not appear on the reproduced picture. CONSTITUTION:A synchronizing circuit 6 holds a switching signal inputted from a level comparator 3, waits for the input of the horizontal synchronizing signal HS and outputs to a head output selecting circuit 4. Thereby, the switching signal inputted from the level comparator 3 is outputted to the head output selecting circuit 4 at the timing which does not appear on the reproduced picture and it is cancelled that the noise at the time of switching the head switching selecting circuit 4 appears on the visible part on the reproduced picture.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of a head selection switch mechanism in a magnetic recording/reproducing device.

[Prior Art] FIG. 2 is a block circuit diagram showing an example of the configuration of a part of a conventional magnetic recording/reproducing device. In FIG. 0, (1) is a rotating head, (2) is a head amplifier, (3) 1 is a level comparator, (4) is a head output selection circuit, and (5) is a reproduction signal output terminal.

The reproduction signals obtained by the 0-rotation head (1), the operation of which will be explained next, are each amplified by the head amplifier (2) and supplied to the level comparator (3) and the head output selection circuit (0.Level comparison The head amplifier (3) compares the output levels of the head amplifier (2), outputs a switching signal to the head output selection circuit (0) to select the output of the head amplifier (2) with the higher output level, and The output selection circuit (0) is switched by the switching signal, and a reproduced signal is output from the output terminal (5).

[Problems to be Solved by the Invention] Since the conventional magnetic recording/reproducing device is configured as described above, the head output selection circuit (4
) switch sometimes changed, and the noise at the time of switching could be seen.

This invention was made in order to solve the above-mentioned problems, and provides a magnetic recording/reproducing device in which the noise at the time of switching the output selection circuit (0) does not appear on the visible part of the reproduction screen. The purpose is to

[Means for Solving the Problems] The magnetic recording/reproducing device according to the present invention retains the switching signal output from the level comparator, and in synchronization with the horizontal scanning synchronization signal, outputs the switching signal at a timing that does not appear on the reproduction screen. The present invention is characterized in that it includes a synchronous circuit that outputs the output to the head output switching circuit.

[Function] The synchronization circuit of the present invention outputs the switching signal input from the level comparator to the head output selection circuit in synchronization with the horizontal synchronization signal at a timing that is not displayed on the playback screen, thereby outputting the head output. Switch. Therefore, noise at the time of switching does not appear on the playback screen.

[Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described based on the drawings. 1st
The figure is a block circuit diagram of this embodiment, and the same parts as in FIG. 2 are given the same reference numerals.

In the figure, (6) is a synchronous circuit, and level comparator (3)
The switching signal and the horizontal synchronizing signal Hs are input, and the output thereof is input to the head output selection circuit (0).

Next, the operation will be explained. The synchronization circuit (6) holds the switching signal input from the level comparator (3), waits for the horizontal synchronization signal Hs to be input, and outputs it at a timing when it does not appear on the playback screen.

Therefore, since the head output is switched during a period in which the head output does not appear on the playback screen, it is possible to eliminate noise from appearing on the playback screen when the head is switched.

[Effects of the Invention] As described above, according to the present invention, the head output is switched in synchronization with the horizontal scanning synchronization signal and at a timing when the head does not appear on the playback screen. This has the effect of providing a magnetic recording/reproducing device in which no noise occurs during switching.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing the configuration of the main part of an embodiment of the present invention, and FIG. 2 is a block circuit diagram showing the structure of the main part of a conventional magnetic recording/reproducing apparatus. (1)... Rotating head, (3)... Level comparator,
(4)...Head output selection circuit, (6)...Synchronization circuit. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A level comparator that outputs a switching signal that compares the output levels of a pair of rotating heads and selects the rotating head with a higher reproduction output level, and a rotating head that is controlled by this switching signal and has a higher reproduction output level. In a magnetic recording and reproducing apparatus equipped with a head output switching circuit that selects and outputs the output of the head output, when the switching signal is output from the level comparator, this is held, and when the horizontal synchronization signal is input, the output is displayed on the playback screen. 1. A magnetic recording and reproducing apparatus comprising: a synchronization circuit that outputs a switching signal to the head output switching circuit even when the switching signal does not appear in the head output switching circuit.