Telecommunications – Receiver or analog modulated signal frequency converter – Local control of receiver operation
Reexamination Certificate
2000-05-30
2003-11-25
Nguyen, Lee (Department: 2682)
Telecommunications
Receiver or analog modulated signal frequency converter
Local control of receiver operation
C455S232100, C455S234100, C455S234200, C455S240100, C375S345000
Reexamination Certificate
active
06654594
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to radio automatic gain control circuits (AGC), and more particularly to digital AGC circuits.
BACKGROUND OF THE INVENTION
Many conventional narrow band zero intermediate frequency (ZIF) receivers have slow AGC loop settling times, such as on the order of 6 to 10 milliseconds (msec.), and dynamic ranges that are too narrow, e. g., 85 decibels (dB). These characteristics lead to less than desirable performance in the fading conditions found in mobile and portable radio communication systems, such as paging, personal communication systems, and cellular communication systems. Furthermore, inexact gain control by prior art AGC's increases the difficulty of reducing DC offset, which reduces signaling performance. What is needed is a low cost, low power AGC that is fast, has a dynamic range in excess of 110 dB and provides more exact gain control.
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Hughes James David
Oakley John Richard
Powell, II Clinton C
Chen Sylvia
Dulaney Randi L.
Motorola Inc.
Nguyen Lee
Tran Tuan
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