Title: Direct digital synthesis of precise, stable angle modulated RF signal
Application Number: 99804405 Application Date: 1999.02.23
Publication Number: 1294775 Publication Date: 2001.05.09
Approval Pub. Date: 2003.08.27 Granted Pub. Date: 2003.08.27
International Classifi-cation: H03C3/08;H03C3/09
Applicant(s) Name: Tropian, Inc. Address:
Inventor(s) Name: Earl W. Mccune;Wendell Sander
Attorney & Agent: fu jianjun
Abstract:
    An RF modulator that allows precise, stable phase shifts to be obtained. The modulator uses a PLL structure including an auxiliary feedforward path including an adaptive gain amplifier (411) used to inject a modulation signal into the PLL at a point past a loop filter (403). A phase demodulator (419) recovers from the output of the PLL phase information which is compared in a comparator (417) to the phase information of the modulation signal. A resulting error signal is used to control the gain of the adaptive gain amplifier (411). The modulator compensates for variability of the VCO (405) and other components of the PLL.
Time: 11
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