Oscillators – Automatic frequency stabilization using a phase or frequency... – With reference oscillator or source
Patent
1997-01-08
1998-05-26
Pascal, Robert
Oscillators
Automatic frequency stabilization using a phase or frequency...
With reference oscillator or source
331 25, 331 2, 327105, 327106, 327107, 375376, H03K 380
Patent
active
057572399
ABSTRACT:
A frequency synthesizer which uses a direct digital synthesizer (DDS) to generate a highly accurate periodic signal of a frequency selected from a plurality of reference frequencies. The DDS output signal is bandpass filtered utilizing a clean-up phase lock loop (PLL) to produce a spectrally pure reference signal and promote overall fast settling time. A second or primary phase lock loop, having a much faster settling time than the first PLL, adjusts the frequency of the reference signal generated by the clean-up PLL. In one embodiment, the DDS frequency synthesizer has a digital to analog (DAC) converter coupled to the clean-up PLL. Another embodiment uses a modified DDS (without a DAC or lookup table) and feeds the most significant bit (MSB) or overflow bit from the DAC accumulator into the "clean-up" PLL. In both embodiments, the resulting synthesizer has high spectral purity, fine frequency resolution and a fast settling time. Yet another embodiment uses a switching apparatus to bypass the "clean-up" PLL while it is settling on a new frequency. Once the "clean-up" PLL settles on the new frequency the switches are set to couple the "clean-up" PLL back into the synthesizer apparatus.
REFERENCES:
patent: 4114110 (1978-09-01), Nossen
patent: 4263565 (1981-04-01), Astle
patent: 4410954 (1983-10-01), Wheatley, III
patent: 4413236 (1983-11-01), Sochor
patent: 4516084 (1985-05-01), Crowley
patent: 4835491 (1989-05-01), Coster
patent: 4841256 (1989-06-01), Gastgeb
patent: 4868524 (1989-09-01), Costlow et al.
patent: 4965533 (1990-10-01), Gilmore
patent: 5028887 (1991-07-01), Gilmore
patent: 5152005 (1992-09-01), Bickley
patent: 5353311 (1994-10-01), Hirata et al.
patent: 5541929 (1996-07-01), Jokura
Bryan Bergeron "Direct Digital Synthesis", Communications Quarterly, Summer 1993, pp. 13-28.
Elizabeth C. Kisenwether et al., "Performance Analysis Of The Numerically Controlled Oscillator", 40TH Annual Frequency Control Symposium 1986, IEEE, New York, pp. 373-378.
V. Reinhardt et al., "A Short Survey Of Frequency Synthesizer Techniques", 40TH Annual Frequency Control Symposium 1986, IEEE, New York, pp. 355-365.
Kinkead Arnold
Martin Roger W.
Miller Russell B.
Pascal Robert
Qualcomm Incorporated
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