Detection processes for a 9600 bit/s modem

Clark, A.P.; Fairfield, M.J.

doi:10.1049/ree.1981.0069

Cited by 5 publications

(15 citation statements)

References 9 publications

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“…2.2.a, whereas the attenuation and group delay characteristics of a poor telephone circuit could be as shown in Fig. 2.2.b [23]. The latter circuit is described in Chapter 3.…”

Section: Telephone Circuitsmentioning

confidence: 99%

“…2 , which now becomes a minimum phase sequence with all the roots of its z-transform lying inside or on the unit circle of the z-plane. So the linear filter here concentrates the energy of the sampled impulse response Y towards the earliest samples and at the same time removing the phase distortion introduced by the channel, without, however, changing any amplitude distortion [22,23]. Thus the signaVnoise ratio at the output of the linear filter is not changed and so this arrangement is optimum in terms of its tolerance to additive white Gaussian noise (since the signaVnoise ratio is unchanged through the pure nonlinear equalizer as described earlier).…”

Section: Nonllnear Equalizermentioning

confidence: 99%

“…These are detectors operating with fewer stored vectors (possible data sequences) and, therefore, with less computation requirements than the Viterbi algorithm detector [23,[43][44][45][46][47][48][49][50][51][52][53][54][55][56][57]. Many of these detectors come close to achieving the maximum likelihood detection (minimum distance) of the received signal, and so they are known as near maximum likelihood detectors.…”

Section: Near-maximum Likelihood Detectorsmentioning

confidence: 99%

“…Many of these detectors come close to achieving the maximum likelihood detection (minimum distance) of the received signal, and so they are known as near maximum likelihood detectors. an adaptive allpass linear filter that is adjusted to make the sampled impulse response of the channel and the filter minimum phase [23,57). The adaptive linear filter here is similar to the linear filter which forms the first part of the optimum nonlinear equalizer [23,[44][45][46][47].…”

Section: Near-maximum Likelihood Detectorsmentioning

confidence: 99%

“…The equipment filters used here are models of practical filters that have been designed for 43 an actual modem by M. J. Fairfield [23,47]. The attenuation and group-delay characteristics of the filters are shown in Fig.…”

Section: @The Equipment Filters and Telephone Circuitsmentioning

confidence: 99%

See 4 more Smart Citations

Detection of coded and distorted QAM signals

Clark

Kadhim

1988

J. Inst. Electron. Radio Eng. UK

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“…2.2.a, whereas the attenuation and group delay characteristics of a poor telephone circuit could be as shown in Fig. 2.2.b [23]. The latter circuit is described in Chapter 3.…”

Section: Telephone Circuitsmentioning

confidence: 99%

Section: Nonllnear Equalizermentioning

confidence: 99%

Section: Near-maximum Likelihood Detectorsmentioning

confidence: 99%

Section: Near-maximum Likelihood Detectorsmentioning

confidence: 99%

Section: @The Equipment Filters and Telephone Circuitsmentioning

confidence: 99%

See 3 more Smart Citations

Detection of coded and distorted QAM signals

Clark

Kadhim

1988

J. Inst. Electron. Radio Eng. UK

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Improved channel estimator for an HF radio link

Clark

McVerry

1983

Signal Processing

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Detection process of a 9600 bit/s serial modem for HF radio links

Clark¹,

Najdi²

1983

IEE Proc. F Commun. Radar Signal Process. UK

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The paper describes a near-maximum-likelihood detection process suitable for use in a synchronous serial digital data transmission system that operates at 9600 bit/s over an HF radio link. The data signal at the input and output of the HF radio link is here a 2400 baud 16-level QAM signal with a bandwidth (measured between the 6 dB points) from about 600 to 3000 Hz. The detector is a development of a technique that operates at 2400 bit/s with a four-level QAM signal and which itself originated from a reduced-state Viterbialgorithm detector. Results of computer simulation tests are presented, showing the tolerance to additive white Gaussian noise of a 9600 bit/s data transmission system employing the new detector and operating over a model of an HF radio link. The latter has two independent Rayleigh fading sky waves that introduce frequency spreads of 0.5 or 2 Hz into the data signal and have a relative transmission delay of 1 or 3 ms. It is assumed that the correct estimation of the channel is achieved at the receiver. List of principal symbols = component of the cost d k of a vector P k (eqns. 26-28) = component of the cost d' k of a vector P k (eqns. 30-32) = cost of vector P k (eqn. 29) = alternative cost of vector P k (eqn. 33) e(k) flf+1 j m n Q k T = location of component of Y k+f{k) with the greatest absolute value, over the first f(k) components (eqn. 21 and expr. 22) = location of first significant component of Y k+f{k) (eqn. 21 and expr. 22) = number of components of Y { (eqn. 3)

show abstract

Detection processes for a 9600 bit/s modem

Cited by 5 publications

References 9 publications

Detection of coded and distorted QAM signals

Detection of coded and distorted QAM signals

Improved channel estimator for an HF radio link

Detection process of a 9600 bit/s serial modem for HF radio links

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