Browse Prior Art Database

EQUALIZER CIRCUIT FOR DATA TRANSMISSION SYSTEM

IP.com Disclosure Number: IPCOM000022899D
Original Publication Date: 1976-Apr-30
Included in the Prior Art Database: 2004-Mar-27
Document File: 2 page(s) / 425K

Publishing Venue

Xerox Disclosure Journal

Abstract

An equalization apparatus is shown above for use in a trans~ mission system in which a train comprising a predetermined number of discrete test pulses is transmitted either from a separate pulse source 11 or from a data source 12 prior to the transmission of any data. The series train of pulses may be modulated by an FM modulator 14 and transmitted over a channel 15 having a limited bandwidth capability, such as an ordinary telephone line. The transmission channel 15 introduces frequency dependent phase delay and amplitude attenuation to the test pulses before they are received by the receiver.

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Page 1 of 2

XEROX DISCLOSURE JOURNAL

EQUALIZER CIRCUIT FOR DATA
TRANSMISSION SYSTEM
N, G, Vinter

Proposed Classification
U.S. CL 333/18
mt. CL H03g 11/04

An equalization apparatus is shown above for use in a trans~
mission system in which a train comprising a predetermined
number of discrete test pulses is transmitted either from a
separate pulse source 11 or from a data source 12 prior to
the transmission of any data. The series train of pulses
may be modulated by an FM modulator 14 and transmitted over
a channel 15 having a limited bandwidth capability, such as
an ordinary telephone line. The transmission channel 15
introduces frequency dependent phase delay and amplitude
attenuation to the test pulses before they are received by
the receiver.

At the receiver, the incoming pulses are transmitted through
an adjustable equalization network 20, demodulated to base~
band by a suitable demodulator 21 and then applied to a data
utilization means or data sink 22, The adjustable equaliza~
tion network 20 comprises an amplifier 25, all pass~delay

networks Fl F5 and switches Sl S5 connected in series
cascade as shown, The apparatus also includes a carrier

Volume 1 Number 4 April 1976 71

[This page contains 1 picture or other non-text object]

Page 2 of 2

EQUALIZER CIRCUIT FOR DATA TRANSMISSION SYSTEM (Cont~d)

detector 27 for detecting the modulated carrier signal. The
detected carrier signal is used to actuate a control logic

circuitry 29. The apparatus also includes a peak-to-average
difference (PAD) detector 31 for deriving signals represen-

tative of the phase and amplitude distortion suffered by the
test pulses. The PAD detector 31 is coupled to the output
of the demodulator 21 so that the combined effects of the
transmission line 15 and the adjustable e...