| US 7,336,134 B1 | ||
| Digitally controlled oscillator | ||
| Stephen T. Janesch, Greensboro, N.C. (US); and Paul G. Martyniuk, Somerville, Mass. (US) | ||
| Assigned to RF Micro Devices, Inc., Greensboro, N.C. (US) | ||
| Filed on Jun. 25, 2004, as Appl. No. 10/877,295. | ||
| Int. Cl. H03B 5/12 (2006.01); H03I 7/099 (2006.01) | ||
| U.S. Cl. 331—36C [331/117 R; 331/57; 331/177 V; 331/185] | 11 Claims |
| 1. A digitally controlled oscillator comprising:
a first controllable component controlling a first parameter affecting an output frequency of the digitally controlled oscillator,
wherein:
said first controllable component comprises a bank of capacitors;
said first parameter comprises capacitance; and
said first controllable component is adapted to be controlled by a first digital word to effectuate coarse tuning of the digitally
controlled oscillator;
a current digital to analog converter (CDAC) controlling a second parameter affecting the output frequency of the digitally
controlled oscillator, wherein said CDAC is adapted to be controlled by a second digital word to effectuate fine tuning of
the digitally controlled oscillator and the second parameter includes a variable bias current provided to the first controllable
component; and
a third controllable component controlling a third parameter affecting the output frequency of the digitally controlled oscillator,
wherein:
said third controllable component comprises a bank of varactors;
said third parameter comprises capacitance; and
said third controllable component is adapted to be controlled by a third digital word to effectuate an intermediate level
of tuning of the digitally controlled oscillator.
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