JPS62128606A - Waveform equalizer - Google Patents

Abstract

PURPOSE:To reduce the interference between pulses by attenuating the amplitude at a part where an input pulse has a gentle slope to reduce the pulse width. CONSTITUTION:An input waveform is turned into a pulse E7 having its rear end part more gentle than the front end part at an input point 7. The delay time of a delay line 2 is demoted as TD then a waveform E9 which is delayed by the input E7 by a delay time TD and attenuated by an attenuator 4 is obtained at an inverse input 9 of a differential amplifier 6. Here no reflection is produced by a termination resistance 3 at the input 6 and the input E7 is obtained as it is at a non-inverse input 8 in the form of a waveform E8 containing no synthesized reflected wave. Then a waveform E10 is obtained at an output 10. This waveform E10 has its pulse width reduced compared with the input E7 and a form more approximate to a front-back symmetrical form in terms of a peak point. In such a way, the interference can be reduced between adjacent pulses.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a waveform equalizer in a reproduction circuit of a storage device.

[Conventional technology]

Figure 5 shows, for example, the technical report NK-67 of Japan Telecommunications Technology @).
59 "Reproduction Waveform Modification in Magnetic Recording" is a block diagram of a conventional waveform equalizer in a reproduction circuit of a storage device, in which (1) is a matching resistor, (2) is a delay line, and (4) is an attenuation. (6) is a differential amplifier. (7) to (9) are the input points of each block, and αα is the output point.

Next, the operation will be explained with reference to FIG. 6, which shows waveforms at various parts in FIG. 5. In this case, if the input waveform to the input terminal () is E7 and the delay time of the delay line (2) is TD, then the non-inverting input (8) of the differential amplifier (6) is E7.
and the non-inverting input of the differential amplifier (6) (reflected at 81,
The reflected wave further delayed by time TD from E8 is combined and attenuated by the attenuator (4) to obtain a waveform]11i9 at the inverting input (9) of the differential amplifier (6). Then, the output of the differential amplifier (6) (in 11, a waveform Ell with a narrower pulse width than K7) is obtained.

In this way, in the conventional equalizer, the amplitude of both edges of the input signal is calculated using the delay time TD of the delay line (2) and the attenuator (4).
The pulse width is narrowed by attenuating the pulse symmetrically with respect to the peak point of the pulse to a degree determined by the attenuation rate. Therefore, this waveform equalizer can narrow the pulse width without damaging the symmetry for pulses that are symmetrical about the peak point, such as E7, and reduce mutual interference between adjacent pulses. It is effective.

[Problems to be solved by the invention] Since the conventional waveform equalizer is configured as shown in 5 above,
The input waveform must be symmetrical with respect to the peak point, and K is inappropriate for handling asymmetrical waveforms.
Alternatively, since the asymmetry is exacerbated, there is a problem in that the effect of reducing mutual interference between adjacent pulses cannot be obtained.

This invention was made to solve the above-mentioned problems, and when dealing with front-back asymmetrical pulses as input waveforms, it is possible to make them as symmetrical as possible, narrow the pulse width, and prevent mutual interference between adjacent pulses. It is an object of the present invention to obtain a waveform equalizer that can reduce the amount of noise and has a high 2-equalization effect.

[Means for solving problems]

The waveform equalizer according to the present invention includes a delay line that delays a matched input signal for a predetermined time, an attenuator that attenuates either the output signal of the delay line or the input signal at a predetermined rate, and the attenuator. and a differential amplifier that inputs the output signal of the delay line or the force signal that is not input to the attenuator among the matched input signals through a pairing resistor and performs analog calculation, and the delay line A terminating resistor is provided to terminate the line.

[Effect]

The attenuator in this invention attenuates the output signal of the delay line or the matched input signal at a predetermined rate, and the differential amplifier performs an analog calculation using the attenuated signal f, and the unattenuated signal shifted by one time. Therefore, for an input pulse whose waveform is asymmetrical with respect to the peak point, by attenuating the amplitude of the part with a gentle slope, the output pulse can be made closer to a symmetrical shape and the pulse width can be narrowed. The terminating resistor also prevents reflected waves from the differential amplifier.

[Embodiments of the invention]

An embodiment of the present invention will be described below regarding a prisoner. 1st
The figure is a block diagram of an embodiment of the present invention. In this figure, an input signal (7) is received by a matching resistor (1);
This output is branched to a pairing resistor (5) and a delay line (21. The output of the pairing resistor (5) is branched to a differential amplifier (6).
) is connected to the non-inverting input of -Power.

The output of the delay line (2) is terminated by a single terminating resistor (3). Furthermore, the intermediate tap of the delay line (2) is an attenuator (4).
and is led to the inverting input of the differential amplifier (6).

An output signal a1 corresponding to the input of the differential amplifier (6) can be obtained from the output of the differential amplifier (6).

Note that the terminating resistor (3) has a value equal to the characteristic impedance value of the delay line (2), and terminates the delay line to prevent signal reflection. It is paired with the attenuator (4:) with a value equal to .

Next, I will explain the trap operation. FIG. 2 shows the waveforms of each part of 1-. In the figure, the input waveform at input point (7) is E7
If the slope of the trailing edge is gentler than that of the leading edge, and the delay time of the delay line (2) is TD, then at the inverting input (9) of the differential amplifier (6).

A waveform E9 is obtained which is delayed by the time TD from IC7 and attenuated by the attenuator (4).

Furthermore, no reflection occurs at the inverting input (9) of the differential amplifier (6) due to the termination resistor (3) K, and the input E7 is obtained as it is as a waveform E8 in which reflected waves are not synthesized at the non-inverting input (8). In the output OQ, the pulse width is narrower than that of E7, and the waveform IJo is close to being symmetrical with respect to the peak point.
get.

In this way, with the equalization amount of this invention, the delay ffM (z)
The pulse width is narrowed by attenuating the amplitude of the trailing edge of the pulse to a degree determined by the delay time Tl) and the attenuation rate of the attenuator (4). Therefore, this equalization amount can make an input pulse, such as E7, whose trailing edge has a gentler slope than the leading edge, become more symmetrical and narrow the pulse width.

This is effective in reducing mutual interference between adjacent pulses.

In the above embodiment, the input pulse was treated as an input pulse in which the slope of the trailing edge was gentler than that of the leading edge, but FIG. This will be explained with reference to an example.

In Figure 3, the output from the matching resistor (1) is the attenuator (
4) and delay i (21K branched, and the output of the attenuator (4) is connected to the inverting input of the differential amplifier (6) from the intermediate tap of the delay line (2) through the pairing resistor (5) to the differential amplifier ( 6
) is input to the non-inverting input.

FIG. 4 shows waveforms at various parts in FIG. That is, the same symbols in the figures indicate the same or equivalent parts.

If the input waveform is E7, the waveform at the non-inverting input (8) of the differential amplifier (6) is E8, and the waveform at the inverting input (9) is E9. The output α@ becomes ]lJo.

〔Effect of the invention〕

As described above, according to the present invention, the pulse width is narrowed by attenuating the amplitude of the part where the slope of the input pulse is gentle. This has the effect of reducing interference between adjacent pulses by narrowing the pulse width while approaching the shape.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of this invention, FIG. 2 is a diagram showing waveforms of each part of FIG. 1, FIG. 3 is a block diagram of another embodiment of this invention, and FIG. FIG. 5 is a block diagram of a conventional waveform equalizer, and FIG. 6 is a diagram showing waveforms of each part in FIG. 5. In the figure, (1) is a matching resistor, (2) is a delay line, and (3
) is the termination resistor, (41 is the attenuator, (5) is the pairing resistor, and (6) is the differential amplifier.

Claims (3)

[Claims] (1) A delay line that matches and inputs an input signal using a matching resistor and delays it for a predetermined time, a terminating resistor that terminates the delay line with a value equal to the characteristic impedance value of this delay line, and the matching resistor. or the output amplitude of the delay line and attenuates it at a predetermined rate, and the output of the matching resistor or the output of the delay line, and the non-input side output of this attenuator is input. and a pairing resistor that pairs with this attenuator with a value equal to the series resistance value of this attenuator, the output of this pairing resistor as a non-inverting input, and the output of the above attenuator as an inverting input. 1. A waveform equalizer comprising: a differential amplifier that performs analog calculations and outputs the results. (2) The waveform equalizer according to claim 1, wherein the attenuator inputs the output of the delay line and attenuates it at a predetermined rate, and the pairing resistor inputs the output from the matching resistor. . (3) The waveform equalizer according to claim 1, wherein the attenuator inputs the output of the matching resistor and attenuates it at a predetermined rate, and the pairing resistor inputs the output of the delay line. .