Experimental Transversal Equalizer for TD-2 Radio Relay System

Bellows, B. C.; Graham, R. S.

doi:10.1002/j.1538-7305.1957.tb01517.x

Cited by 7 publications

(2 citation statements)

References 7 publications

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“…. (12) which represents a cosine series, apart from a phase shift which is independent of the coefficients a m and irrelevant here. The cosine shapes refer to the transfer ratio rather than to its logarithm (or gain), but this is without significance, since the whole series is produced in one single network and not in a tandem connection of separate networks, each producing one term.…”

Section: + 2 a N C O S Nb)mentioning

confidence: 99%

Residual attenuation equalisation of broadband systems by generalised transversal networks

Linke

1967

Proc. Inst. Electr. Eng. UK

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SynopsisResidual attenuation equalisation of broadband coaxial-cable systems has been achieved elsewhere by a set of harmonic cosine characteristics based on an almost linear frequency scale. This method is, however, not efficient for systems which exhibit high distortion near the bandedges. A simple analysis of measured characteristics yields the requirements for suitably transforming, or 'warping', the frequency scale. Generalisations of the transversal-equaliser principle offer the realisation of cosine characteristics with frequency scales which match particular problems. The investigation on which the paper is based was concerned with the coaxial-cable network of the British Post Office, and led to novel designs, of which the 'twin cosine equaliser' has been accepted for service use. This device enables residual distortion of up to 6dB to be reduced to rather less than 1 dB, with a minimum of auxiliary instrumentation. List of symbolsa, b, c = coefficients m, r, s, u,v = indexes v = integer n = order oil = Irfi = lower frequency limit of system a> h = 277-//, = upper frequency limit of system a>1 ~~ J 7 ''} > = limits of approximation interval o; 2 = 277/ 2 J co 0 , 00 r = reference frequenciesx(f) = transformation ('warping') of frequency scale y = normalised frequency F(x) = function to be approximated S n = trigonometric sum of nth order S n = truncated Fourier series of nth order M(d) = modulus of convergence d = limit to modulus of increment of variable /difference or differential quotient Islope of polygon side = constant in Jackson's theorem = quantisation step q = upper limit to equalisation error, dB A + jB = propagation coefficient A o = In k = flat loss of variable equaliser R = resistance W = characteristic impedance K = impedance ratio N = number of components E, U = signal amplitudes T = time constant G(co) = transfer function (output/input ratio) m = shape parameter (j) af (f) b = pair of quadrature phase-shift functions

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Section: + 2 a N C O S Nb)mentioning

confidence: 99%

Residual attenuation equalisation of broadband systems by generalised transversal networks

Linke

1967

Proc. Inst. Electr. Eng. UK

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“…Y( » IS THE MATHEMATICAL EXPRESSION C FOR THIS DELAY AS USED IN THE EQUALIZER EVALUATION. IF(KZ.GE.KVARI GO TO 502 KZ=KZ+1 WRITE(3,190) KZ,N,AM,SD,REJ 190 FORMAT*'1',# DELAY SECTION VARIATION SUB-RUN NO. ',13,', FOR',13,' ITOTAL TAP POINTS.…”

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confidence: 99%

Automatic amplitude and phase equalization derived from frequency-domain data

Bliss

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frequency-domain measurements of the channel characteristic. The equalizer is to be utilized in a data communication system as shown in Figure 1. The frequency-domain measurements are assumed to be made in an interval of 1 to 3 minutes after the channel routing has been established. An accurate computercontrolled measurement device capable of accomplishing this, assuming suitable switching automation, has been recently described by Reynolds [38]. This investigation considers the feasibility of converting such measurements into equalizer adjustment values. The method chosen for evaluating the conversion algo rithm is to simulate the equalizer and its control routine using a digital computer program. Special test cases to verify proper solution via the routine are reported, follow ed by equalization simulation results for typical channel characteristics. The effects of some implementation hardware parameters are investigated. Unique operational features of the scheme are also modeled, to establish the utility of the technique. The tapped delay line equalizer simulation model is identified as program EQLR.

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A Transversal Equalizer for Television Circuits

Sperry¹,

Surenian²

1960

Bell System Technical Journal

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Transmission of television signals over long systems requires a fine degree of equalization. An adjustable type of equalizer to supplement fixed equalizers is discussed. It provides both gain and delay characteristics in the form of harmonically related cosine shapes which are independently adjustable. The design and operation of the equalizer is explained on the basis of paired echo theory. The 336A equalizer used in the L3 coaxial system is discussed as an example of this equalization technique.

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Experimental Transversal Equalizer for TD-2 Radio Relay System

Cited by 7 publications

References 7 publications

Residual attenuation equalisation of broadband systems by generalised transversal networks

Residual attenuation equalisation of broadband systems by generalised transversal networks

Automatic amplitude and phase equalization derived from frequency-domain data

A Transversal Equalizer for Television Circuits

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