KR0165276B1 - Equipment for data reproduction - Google Patents

Abstract

A data reproducing apparatus for reproducing digital data from a reproducing signal generated through a pickup device of a digital video tape recorder is disclosed.

A data reproducing apparatus according to the present invention comprises: a differentiator for inputting a modulated signal; An inverting / non-inverting amplifier for inputting a differential reproduction signal generated in the differentiator; A comparator for inputting an inverted and non-inverted signal generated by the inverted / non-inverted amplifier; A latch for inputting a comparison output of the comparator; And a gate pulse generator for inputting a modulation signal and generating a gate signal for activating the latch in the peak period thereof.

The data reproducing apparatus according to the present invention inverts / non-inverts amplified derivative signals and reproduces the data by comparing the inverted-amplified signals with the non-inverted amplified signals, thereby accurately correcting the data without being affected by the level fluctuation of the reproduced signals. It has an effect that can be played back.

Description

Data playback device

1 is a block diagram showing a data reproducing apparatus according to the prior art.

2 is a waveform diagram showing the operation of FIG.

3 is a block diagram showing an embodiment of a data reproducing apparatus according to the present invention.

4 is a waveform diagram showing the operation of FIG.

5 is a block diagram showing another embodiment of the data reproducing apparatus according to the present invention.

6 is a timing diagram showing the operation of the apparatus shown in FIG.

The present invention relates to a data reproducing apparatus for reproducing digital data from a reproducing signal generated through a pickup device of a digital videotape recorder, and more particularly, to an apparatus for preventing a malfunction due to noise.

A digital video tape recorder is an apparatus that converts an analog image signal into digital data and records it on magnetic tape, or reproduces an original image signal from the digital data recorded in this way.

It is modulated into a magnetization signal of alternating current state having a positive peak value at each rising edge of the digital data and a negative peak value at the falling edge, and recorded on a magnetic recording medium. During reproduction, a reproduction signal corresponding to the direction and intensity of the magnetization is detected. Play back digital signals. Specifically, the signal reproduced through the pickup apparatus is subjected to high pass compensation through an equalizer and digital signals are reproduced therefrom.

1 is a block diagram showing a conventional data detection apparatus. In Fig. 1, reference numerals 10 and 12 are comparators and 14 are flip-flops.

The comparators 10 and 12 are applied with a positive reference voltage Vref + and a negative reference voltage Vref− for comparison detection. Outputs of the first comparator 10 and the second comparator 12 are applied to the set signal input terminal and the reset signal input terminal of the pull-flop 14, respectively, to obtain digital data reproduced at the output terminal thereof.

The operation of the apparatus shown in FIG. 1 will be described with reference to the waveform diagram of FIG. 2. First, the modulated signal output from the equalizer (not shown) is defined by the first comparator 10 and the second comparator. It is supplied to the negative input terminal of (12).

The comparators 10 and 12 are applied with a positive reference voltage Vref + and a negative reference voltage Vref− for comparison detection. Accordingly, the first comparator 10 and the second comparator 12 output comparison signals such as waveforms (A) and (B), respectively.

The addition of a zero mark among the output terminals of the second comparator 12 means that the inverted comparison signal is output.

The comparison signal output from the first comparator 10 is applied to the set signal input terminal of the flip-flop 14, and the comparison signal output from the second comparator is applied to the reset signal input terminal. Accordingly, the flip-flop 14 outputs digital data such as the waveform (C). Comparing the digital data output from the flip-flop 14 with the original digital data, it can be seen that the phase data is the same and the same data.

However, the apparatus shown in FIG. 1 has a problem in that it is vulnerable to deterioration or noise of a reproduction signal. In the apparatus shown in FIG. 1, if the output state of the equalizer is unstable, the output from the comparator fluctuates, which is represented by an error in reproduced data.

In addition, the level of the reproduction signal may vary depending on the pickup device, and therefore, which pickup device has to be matched with a comparison voltage.

It is therefore an object of the present invention to provide a data reproducing apparatus capable of accurate data reproducing even when the level of a modulated signal varies.

A data reproducing apparatus according to an embodiment of the present invention for achieving the above object comprises a differentiator for inputting a modulated signal; An inverting / non-inverting amplifier for inputting a differential reproduction signal generated in the differentiator; A comparator for inputting an inverted and non-inverted signal generated by the inverted / non-inverted amplifier; A latch for inputting a comparison output of the comparator; And a gate pulse generator for inputting a modulation signal and generating a gate signal for activating the latch in the peak period thereof.

In accordance with another aspect of the present invention, a data reproducing apparatus includes: a differentiator for inputting a modulated signal; A zero crossing detector for inputting a differential reproduction signal generated at the differential; A latch for inputting a zero crossing pulse detected by the zero crossing detector; And a gate pulse generator for inputting a modulation signal and generating a gate signal for activating the latch in the peak period thereof.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

3 is a diagram showing an embodiment of a data reproducing apparatus according to the present invention. In the apparatus shown in FIG. 3, reference numeral 30 is a differentiator, 32 is an inverting / non-inverting amplifier, 34 is a comparator, 36 is a latch, and 38 is a gate pulse generator.

The gate pulse generator 38 includes an inverting / non-inverting amplifier 38a, retarders 42a and 42b, rectifiers 44a and 44b, low pass filters 46a and 46b, comparators 48a and 48b, and an oragate. 50 is provided.

The operation of the apparatus shown in FIG. 3 will be described in detail with reference to the waveform diagram shown in FIG. The modulated signal in the equalizer (not shown) is differentiated and amplified through the differentiator 30 and the inverting / non-inverting amplifier 32. As a result, a differential modulated signal such as the (K) waveform is obtained at the non-inverted output terminal of the inverted / non-inverted amplifier and the (L) waveform is obtained at the inverted output terminal.

The comparator inputs the signals (k) and (1) and supplies a comparison signal to the latch 36.

In the latch 38, the reproduction data similar to (M) can be obtained.

However, in FIG. 4, glitches caused by various causes are included in the middle part of the (k) and (L) waveforms without inversion of data, and thus, the glitches also appear in the (M) waveform. It can be seen. Therefore, these glitches must be removed and this is made possible by the gate pulse generator 38.

On the other hand, the modulated signal from the equalizer (not shown) is also applied to the gate pulse generator 38. The gate pulse generator 38 generates a gate pulse shown by the waveform (J) in FIG. 4 and applies it as a latch signal of the latch 36.

The latch 36 inputs the gate pulse applied from the gate pulse generator 38 as a latch signal to latch the comparison output from the comparator 36 to output the reproduced data shown by the (M) waveform.

The operation of the gate pulse generator 38 will be described in detail. The non-inverted amplified signal output from the inverting / non-inverting amplifier 40 is formed into a (D) waveform through the delay unit 42a, is applied to the positive input terminal of the comparator 48a, and at the same time as the rectifier 44a. It is formed into the (F) waveform through the filter 46a and applied to the negative input terminal. The comparator 48a compares the signals of (D) and (F) applied to the input terminals of the positive and negative parts, and supplies the comparison output represented by (H) to the oragate 50.

The inverted / amplified modulated signal output from the inverting / non-inverting amplifier 40 is formed into the (E) waveform through the delay unit 42b, and is applied to the positive input terminal of the comparator 48b while simultaneously providing the rectifier 44b and the low pass filter. It is formed into a (G) waveform through 46b and applied to the negative input terminal. The comparator 48b compares the signals of (E) and (G) applied to the input terminals of the positive part and the negative part, and supplies the comparison output represented by (I) to the oragate 50.

OA gate 50 inputs the signals of (H) and (I) to form a gate pulse represented by (J) and provides it as a latch signal of latch 38.

Looking closely at the waveforms of (M) and (J) in FIG. 4, it can be seen that the data is inverted where the waveform of (J) is high and the glitch is generated where it is low. Therefore, when the latch is operated where the gate pulse is high, the (N) waveform without the glitch can be obtained. Comparing the (N) waveform with the original data shows that they are the same.

5 shows another embodiment of the data reproducing apparatus according to the present invention, in which the same reference numerals are used for the same parts as in FIG. The apparatus shown in FIG. 5 will be described with reference to the timing diagram of FIG.

First, the modulated signal differentiated through the differentiator 30 is obtained through the zero cross detector 50 to obtain a pulse signal shown by the (O) waveform of FIG. The pulse signal is reproduced through the flip-flop 52 to reproduce the digital signal. On the other hand, as in the apparatus shown in FIG. 4, the gate pulse generated by the gate pulse generator 38 is applied as an enable signal of the flip-flop 52 to obtain a signal Q from which the glitch has been removed.

As described above, the data reproducing apparatus according to the present invention is not influenced by the level fluctuation of the reproduction signal by reversing / non-inverting amplifying the differentiated reproduction signal and reproducing the data by comparing the inverted-amplified signal with the non-inverted amplified signal. It has the effect of accurately reproducing data without

In addition, the data reproducing apparatus according to the present invention has the advantage of eliminating the influence of the glitch included in the reproduction signal by performing data inversion only in the peak value section of the reproduction signal.

Those familiar with the digital signal processing art will appreciate that there may be many modifications other than those disclosed in this embodiment in constructing the gate pulse generator. For example. A low pass filter of the amplified modulated signal is compared with a modulated signal through one comparator, and an equivalent gate pulse can be generated by inverting only a negative part of the comparison output.

Therefore, it should be noted that the present invention is not limited to the disclosed embodiments.

Claims (6)

An apparatus for reproducing the digital data from a modulated signal formed to have a peak value at each standing / falling edge of the digital data, the apparatus comprising: a differentiator for inputting the modulated signal; An inverting / non-inverting amplifier for inputting the differentiated reproduction signal generated in the differentiator; A comparator for inputting an inverted and non-inverted signal generated by the inverted / non-inverted amplifier; A latch for inputting a comparison output of the comparator; And means for inputting the modulation signal and generating a gate signal for activating the latch in its peak section. 2. The apparatus of claim 1, wherein the gate pulse generating means comprises: an inverting / non-inverting amplifier for inputting the modulation signal; A first half-wave rectifier for inputting a non-inverted amplified modulated signal detected by the inverted / non-inverted amplifier; A first low-pass filter for inputting a positive pulse wave generated in the first half-wave rectifier; A first comparator configured to input a non-inverted amplified signal generated by the inverted / non-inverted amplifier and a low-pass filtered signal generated by the first low pass filter; A second half-wave rectifier for inputting an inverted-amplified modulated signal generated by the inverted / non-inverted amplifier; A second low pass filter for inputting negative pulses detected by the second half-wave rectifier; A second comparator for inputting an inverted modulated signal generated by the inverted / non-inverted amplifier and a low pass filtered signal generated by the second low pass filter; And an orifice for inputting a comparison output generated by the first comparator and the second comparator and providing the output as a latch signal of the latch. 3. The gate delay generator of claim 2, wherein the gate pulse generator further comprises a first delay unit and a second delay unit delaying the inverted and non-inverted modulated signals generated by the inverted / non-inverted amplifier by a predetermined time, respectively. A data reproducing apparatus, characterized in that provided. An apparatus for reproducing the digital data from a modulated signal formed to have a peak value at each standing / falling edge of the digital data, the apparatus comprising: a differentiator for inputting the modulated signal; A zero crossing detector for inputting the differentiated reproduction signal generated in the differentiator; A latch for inputting a zero crossing pulse detected by the zero crossing detector; And means for inputting the modulated signal and generating a gate signal that activates the latch in its peak section. 5. The apparatus of claim 4, wherein the gate pulse generating means comprises: an inverting / non-inverting amplifier for inputting the modulation signal; A first half-wave rectifier for inputting a non-inverted amplified modulated signal detected by the inverted / non-inverted amplifier; A first low-pass filter for inputting a positive pulse wave generated in the first half-wave rectifier; A first comparator configured to input a non-inverted amplified signal generated by the inverted / non-inverted amplifier and a low-pass filtered signal generated by the first low pass filter; A second half-wave rectifier for inputting an inverted-amplified modulated signal generated by the inverted / non-inverted amplifier; A second low pass filter for inputting negative pulses detected by the second half-wave rectifier; A second comparator for inputting an inverted modulated signal generated by the inverted / non-inverted amplifier and a low pass filtered signal generated by the second low pass filter; And an orifice for inputting a comparison output generated by the first comparator and the second comparator and providing the output as a latch signal of the latch. 6. The apparatus of claim 5, wherein the gate pulse generating means further comprises a first delayer and a second delayer for delaying each of the inverted and non-inverted modulated signals generated by the inverted / non-inverted amplifier by a predetermined time. A data reproducing apparatus, characterized in that provided.