Pulse or digital communications – Repeaters – Testing
Patent
1984-03-27
1987-10-20
Griffin, Robert L.
Pulse or digital communications
Repeaters
Testing
364724, H03H 730, H03K 5159
Patent
active
047019360
ABSTRACT:
Filters are provided at the outputs of data transmission links to overcome attenuation distortion and phase distortion but such filters tend to increase the noise content of received signals. In the present invention a filter coupled to a linear baseband channel is constrained to be an all pass network, thus avoiding any noise enhancement at its output. The filter is adjusted using a channel estimator and an adjustment system to give the channel plus the filter an impulse-response that rises rapidly to its peak, thus simplifying the detection process needed for a satisfactory tolerance to noise. The required response is obtained by finding those roots (zeros) of the z transform of the sampled impulse-response of the channel, which have a modulus greater than some given value which is not less than unity, and adjusting the filter such that, in the z transform of the sampled impulse-response of the channel and filter, the roots are replaced by the complex conjugates of their reciprocals, the remaining roots of the channel z-transform being left unchanged.
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Clark Adrian P.
Hau Sau F.
Chin Stephen
Griffin Robert L.
National Research Development Corporation
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