04009450 is referenced by 15 patents and cites 4 patents.

In a tracking filter, which includes a conventional phase locked loop having a phase detector, a filter and a voltage controlled oscillator adapted to track a wanted signal and attenuate unwanted signals and noise from an incoming spectrum of signals, there is provided a phase modulator and an additional filter adapted to attenuate further the unwanted signals and the noise without degrading the ability of the loop to track the wanted signal.

Title
Phase locked loop tracking filter having enhanced attenuation of unwanted signals
Application Number
5/568073
Publication Number
4009450
Application Date
April 14, 1975
Publication Date
February 22, 1977
Inventor
Arthur J Kline Jr
Scottsdale
AZ, US
Don R Holcomb
Phoenix
AZ, US
Agent
Harry M Weiss
Eugene A Parsons
Assignee
Motorola
IL, US
IPC
H03B 3/04
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