KR960038862A - Automatic gain compensation device for trick play - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a trick reproducing apparatus of a digital video cassette recorder, and in particular, an automatic gain compensating apparatus for trick reproducing, which compensates the repetitive reduction in the output level of a reproduction signal during a trick replay. It is about. The present invention corrects a waveform of a signal that has been reproduced and amplified during trick reproduction by an impedance value obtained from the envelope waveform of the reproduced amplification signal. Therefore, the automatic gain compensation device for trick play according to the present invention makes the level of the output signal even during trick play as in normal play. In addition, it has an effect of improving the bit error rate of the system during trick play.

Description

Automatic gain compensation device for trick play

As this is a public information case, the full text was not included.

FIG. 2A shows the trajectory of the head on the tape when the tape is played back at 9 times speed in FIG. 1, FIG. 2B shows the output waveform of the head, and FIG. 3 shows the trick reproduction according to the present invention. Fig. 4 is a block diagram showing a digital system of a digital VD (D-VCR) including an automatic gain compensation device. Fig. 4 is an input / output waveform diagram of each part of the automatic gain compensation device in Fig. 3;

Claims (5)

An apparatus for recording and reproducing digital signals using a magnetic recording medium, comprising: a switch switched by inputting a selection signal for a normal reproduction or trick reproduction mode from a user; A delayer for delaying and outputting a reproduction signal read from the reproduction head for a predetermined time when the switch is connected to the trick reproduction mode; A potential detection unit for detecting an envelope waveform of the reproduction signal and outputting a voltage having an antiphase value of a waveform proportional to the reproduction signal and applying it to a voltage controlled oscillator; A voltage controlled oscillator for generating an oscillation frequency proportional to the voltage; And a gain control unit for adjusting a gain of a reproduction signal applied from the delay unit according to the oscillation frequency. The electronic device of claim 1, wherein the potential detection unit comprises: a rectifier for full-wave rectifying the reproduction signal; And an inverting integrator for integrating the rectified signal and outputting an inverted phase of the rectified signal. The oscillator of claim 1, wherein the gain control unit comprises: a variable resistor unit having an impedance value inversely proportional to an oscillation frequency of the voltage controlled oscillator; And a gain adjusting unit for adjusting the gain of the reproduction signal according to the impedance value. 4. The apparatus of claim 3, wherein the variable resistor unit comprises: a plurality of switches connected in series; And a condenser connected in parallel with the switches. 4. The apparatus of claim 3, wherein the gain adjusting unit comprises: an amplifier for adjusting a gain of the reproduction signal according to the impedance value; And a resistor connected between the input and output terminals of the amplifier. ※ Note: This is to be disclosed by the original application.