A Simple Adaptive Equalizer for Efficient Data Transmission

Hirsch, Derrick D.; Wolf, W.

doi:10.1109/tcom.1970.1090325

Cited by 66 publications

(5 citation statements)

References 3 publications

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“…All of the coefficients are controlled independently by the coefficient controller. The controller adaptively handles all of the coefficients in compliance with error £ and tap data, with the modified zero forcing method (M2;F method) [10]. An adaptive digital filter eliminates crosstalk in the main signal, by generating a crosstalk component replica, having an opposite polarity, of the crosstalk component from sub-signals and adding them.…”

Section: Crosstalk Canceller Methodsmentioning

confidence: 99%

“…The controller consists of the error detector and nine correlators. The controller adaptively handles all of the coefficients in compliance with error e and tap data, with the MZF method [10], and changes the filter characteristics through outputting the equalized data at the lowest error rate. This equalizer can eliminate intersymbol interference in high linear density recording and handle various partial response ( PR ) equalization by virtue of the error detector.…”

Section: Prml Methodsmentioning

confidence: 99%

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High Density Land/Groove Recording

Iwanaga

1995

J. Magn. Soc. Jpn.

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In order to achieve higher areal density recording, both land and groove area recording (Land/Groove recording) technology has been developed. In the Land/Groove recording method, the combination with crosstalk canceller and PRML technique has a potential for over achieving lOX MO recording in realizing larger capacity. Moreover, it is also possible to accomplish 16X MO recording, using the blue green laser head combined system.

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Section: Crosstalk Canceller Methodsmentioning

confidence: 99%

Section: Prml Methodsmentioning

confidence: 99%

High Density Land/Groove Recording

Iwanaga

1995

J. Magn. Soc. Jpn.

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“…Up to the 1990s, a channel equalization process was mainly used in coherent acoustic communication to compensate for the ISI [2,[10][11][12]. Furthermore, a single-channel receiver was extended to the multichannel receiver system to improve the communication performance.…”

Section: Introductionmentioning

confidence: 99%

Estimate of Passive Time Reversal Communication Performance in Shallow Water

et al. 2017

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Time reversal processes have been used to improve communication performance in the severe underwater communication environment characterized by significant multipath channels by reducing inter-symbol interference and increasing signal-to-noise ratio. In general, the performance of the time reversal is strongly related to the behavior of the q-function, which is estimated by a sum of the autocorrelation of the channel impulse response for each channel in the receiver array. The q-function depends on the complexity of the communication channel, the number of channel elements and their spacing. A q-function with a high side-lobe level and a main-lobe width wider than the symbol duration creates a residual ISI (inter-symbol interference), which makes communication difficult even after time reversal is applied. In this paper, we propose a new parameter, E q , to describe the performance of time reversal communication. E q is an estimate of how much of the q-function lies within one symbol duration. The values of E q were estimated using communication data acquired at two different sites: one in which the sound speed ratio of sediment to water was less than unity and one where the ratio was higher than unity. Finally, the parameter E q was compared to the bit error rate and the output signal-to-noise ratio obtained after the time reversal operation. The results show that these parameters are strongly correlated to the parameter E q .

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“…Various algorithms have been developed to automatically adjust the tap-gain settings in such an equalizer during a training period in which a train of isolated reference pulses is transmitted [I -3]. Adaptiveness can be achieved during actual data transmission by adjusting the tap-gain settings as a function of estimated channel response [4][5][6][7]. It is clear that, for high-speed data transmission systems, fast convergence in automatic equalization is important to keep the turn-around time small.…”

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confidence: 99%

A New Class of Automatic Equalizers

Sha

Tang

1972

IBM J. Res. & Dev.

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A new class of automatic equalizers with very fast convergence is discussed in this paper. This fast convergence is accomplished by means of an iterative procedure which successively makes higher-order approximations on the desired equalizer function.The iterative procedure can be conveniently realized in the form of transversal filter stages in casSflde. For a given distortion D < 1, the residual distortion at the equalizer output after I'! iterations can be reduced to no more than D 2 in the noise-free cases. When this approach is applied to the feed-forward part of a recursive structure, the front distortion (due to precursors) can be reduced in a similar fashion without unduly increasing the overall distortion. The resulting distortion, mainly in the rear end, can then be cancelled out via feedback paths. Other topics treated include certain generalizations, the truncation error due to limited length in cascaded equalizer sections, and the effect of noise. Several numerical examples are also presented to illustrate the effectiveness of the approach. 556 IntroductionOne of the significant developments in recent years in digital data transmission has been the use of transversal filters as time-domain equalizers. Various algorithms have been developed to automatically adjust the tap-gain settings in such an equalizer during a training period in which a train of isolated reference pulses is transmitted [I -3]. Adaptiveness can be achieved during actual data transmission by adjusting the tap-gain settings as a function of estimated channel response [4][5][6][7]. It is clear that, for high-speed data transmission systems, fast convergence in automatic equalization is important to keep the turn-around time small. In this paper, we describe a new equalization technique with very fast convergence time. The technique is based on an iterative procedure that makes successively higher-order approximations on the desired equalizer transfer function. This procedure can be conveniently implemented in the form of cascaded transversal filter stages. We also describe how this technique can be applied to the feed-forward part of a recursive structure, resulting in the suppression of the front distortion without unduly increasing the overall distortion. Other topics treated include certain generalizations of this technique, the effect of truncation (limiting the number of delay units in an equalizer stage), and the effect of noise. Several examples with numerical results obtained via an APL simulation program are also included

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A Simple Adaptive Equalizer for Efficient Data Transmission

Cited by 66 publications

References 3 publications

High Density Land/Groove Recording

High Density Land/Groove Recording

Estimate of Passive Time Reversal Communication Performance in Shallow Water

A New Class of Automatic Equalizers

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