[54] OSCILLATOR MODE SUPPRESSION
APPARATUS HAVING BANDPASS EFFECT
[75] Inventor: John R. Burgoon, Campbell, Calif.
[73] Assignee: Hewlett Packard Company, Palo Alto, Calif.
[21] Appl. No.: 296,746
[22] Filed: Aug. 27,1981
Related U.S. Application Data
[63] Continuation of Ser. No. 26,276, Apr. 2, 1979.
[51] Int. C1.3 H01P 1/18
[52] U.S.' CI 331/158; 331/116 R
[58] Field of Search 331/117 R, 116 R, 158,
331/159, 160, 164
[56] References Cited
U.S. PATENT DOCUMENTS
2,608,648 8/1952 Magnuski 331/164
3,560,879 2/1971 Fuchs 331/158
Primary Examiner—David K. Moore
Attorney, Agent, or Firm—Jon R. Stark; Allston L. Jones
[57] ABSTRACT
An apparatus utilizing the basic oscillation characteristics of the Colpitts or Pierce and Hartley oscillator configurations. In this embodiment the basic shunt reactive shunt arms are replaced with a selected pair of tank circuits or one of the shunt arms with a series-parallel tank circuit.
These tank circuits are tuned such that the sign of their effective reactances are the same between the range of resonant frequencies of the individual tank circuits or of the series and parallel resonant frequencies of the seriesparallel tank. When this occurs and their sign differs from the sign of the effective reactance of the series reactive element, there is a 180° signal phase shift in the feedback loop, and therefore oscillation.
14 Claims, 15 Drawing Figures
