Frederick T Zendt

US Patent:

52670716, Nov 30, 1993

Filed:

Sep 3, 1991

Appl. No.:

7/754029

Inventors:

Frank R. Little - Alpharetta GA
John G. Megna - Lilburn GA
Heather H. Rand - Alpharetta GA
Frederick T. Zendt - Norcross GA

Assignee:

Scientific-Atlanta, Inc. - Norcross GA

International Classification:

H04B 1000

US Classification:

359154

Abstract:

A system for signal level control in AM fiber systems is provided. The system provides level controls at both transmitter and receiver ends of the fiber transmission system, utilizing compensation and control techniques at each end to maintain and optimize the performance of the system. The transmitter includes two stage level control based on a composite power level of a detected RF signal. The receiver includes two stage level control based on a pilot channel filtered from the channels transmitted to the receiver.

US Patent:

49127217, Mar 27, 1990

Filed:

Apr 29, 1988

Appl. No.:

7/188478

Inventors:

Rezin E. Pidgeon - Atlanta GA
Frederick T. Zendt - Norcross GA
Leo J. Thompson - Lilburn GA

Assignee:

Scientific-Atlanta, Inc. - Atlanta GA

International Classification:

H04K 100

US Classification:

375 1

Abstract:

Apparatus for transmitting data spread across at least a portion of the bandwidth of a cable television channel comprises a carrier signal oscillator, a frequency divider, a pseudorandom sequence generator and two exclusive OR gates. A first exclusive OR gate serves to spread a data signal across the pseudorandom noise sequence generator having a much higher chip rate than the bit rate of the data signal. The second exclusive OR gate modulates the spread spectrum data signal to a carrier frequency for transmission over the cable television channel. The apparatus may be applied for return path transmission in the 0-30 megahertz band which is high susceptible to interference noise and provides approximately a 20 dB signal to interference ratio advantage over known data coding and transmission schemes. A microprocessor normally present in a cable television terminal may format data for transmission, control the spread spectrum modulation process and control gain control circuitry for introducing an appropriate power level into the cable plant.