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 Title: |
US4800341:
Fast switching frequency synthesizer
[ Derwent Title ]
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| Country: |
US United States of America
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| Inventor: |
Johnson, Edgar A.; Tujunga, CA
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| Assignee: |
Eaton Corporation, Cleveland, OH
other patents from EATON CORPORATION (161150) (approx. 4,296)
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| Published / Filed: |
1989-01-24
/ 1987-11-02
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| Application Number: |
US1987000115027
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| IPC Code: |
Advanced:
H03L 7/22;
Core:
H03L 7/16;
IPC-7:
H03L 7/16;
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| U.S. Class: |
Current:
331/002;
327/105;
331/025;
Original:
331/002;
331/025;
307/529;
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| Field of Search: |
331/002,25
307/529
455/091,103,113
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| Priority Number: |
| 1987-11-02 |
US1987000115027 |
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| Abstract: |
A synthesizer produces step frequencies by multiplying the frequency of a reference oscillator and stimulating an SRD comb frequency generator, then adding or subtracting a reference frequency. The selected step frequency can be placed on either side of each picket of the comb's spectrum. A fine adjustment frequency is then added in a translation oscillator. The fine frequency component can also be placed on either side of the selected step frequency.
Frequency dividers, which would result in noisy final outputs, are not employed. Instead, the frequency of a reference signal is multiplied up in a narrowband channel to serve as a local oscillator, and the VCO signal frequency is reduced by heterodyning it down from its ultra-high frequency. The down-converted difference frequency is compared as to phase with the reference oscillator. The loop gain and bandwidth are so high in the phase lock loops that output noise is low and switching time is fast.
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| Attorney, Agent or Firm: |
Grace, C. H. ;
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| Primary / Asst. Examiners: |
Laroche, Eugene R.; Pascal, Robert J.
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| Maintenance Status: |
E2 Expired Check current status
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| INPADOC Legal Status: |
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| Family: |
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First Claim:
Show all 15 claims |
What is claimed is:
1. A frequency generator comprising:
- reference frequency means for providing a reference signal of stable frequency and phase;
- frequency multiplier means receiving said reference signal for providing a signal having a multiplied frequency that is at least four time said reference frequency;
- voltage controlled oscillator means (VCO) for providing an AC signal whose frequency is of the same order of magnitude as said multiplied frequency and is controllable by a DC control voltage at a control terminal, said AC signal being perturbed by some phase noise that is manifested as phase angle excursions of said AC signal;
- heterodyne means receiving (a) said VCO AC signal and said noise and (b) said multiplied frequency signal, for providing a down-converted signal and phase noise of undivided phase angle excursions, whose frequency is the difference of the frequencies of said VCO and multiplied signals;
- phase comparator means receiving
- (c) said reference signal and
- (d) said down-converted signal and said phase noise of undivided phase angle excursions,
- for providing a phase error signal indicative of the phase difference between said reference and down-converted signals; and,
- filter means receiving said phase error signal for providing said DC control voltage, with predetermined bandwidth and loop again, to said control terminal of said VCO;
- whereby a phase lock loop is established in which the phase noise perturbing said VCO signal is effectively translated to the phase comparator means with undivided phase angle excursions, to enable corrective feedback of the phase lock loop to effectively reduce the noise.
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| Background / Summary: |
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| Drawing Descriptions: |
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| Description: |
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| Forward References: |
Show 4 U.S. patent(s) that reference this one
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