Pulse or digital communications – Repeaters – Testing
Patent
1989-08-11
1991-07-09
Olms, Douglas W.
Pulse or digital communications
Repeaters
Testing
375101, 375 12, 333 28R, H03H 730
Patent
active
050311948
ABSTRACT:
A digital decision feedback equalizer is disclosed in which compensation for the post-cursors of the impulse response of the transmission channel is divided up into two regions. A first region encompasses the initial rapidly changing unpredictable transient response, possibly oscillatory, of the transmission channel. A fast acting, close-tracking linear filter is used to compensate for this largely unpredictable initial transient. The second region of the impulse response is the slowly changing, easily predictable asymptotic tail of the impulse response. This second region can be compensated for by a relatively slow acting, simple pole-zero filter. Together, the two equalizer sections provide an overall equalizer design far less complicated and less expensive than an equalizer based on a single linear compensating filter. A finite impulse response (FIR) filter is used to compensate for the unpredictable, rapidly changing initial transient portion of the impulse response, while an infinite impulse response (IIR) filter is used to compensate for the slower acting tail portion of the impulse response.
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Crespo Pedro M.
Honig Michael L.
Bell Communications Research Inc.
Falk James W.
Olms Douglas W.
Smith Ralph
Suchyta Leonard Charles
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