| US 7,576,615 B2 | ||
| Multi-point modulation and VCO compensation | ||
| Thomas E. Biedka, San Jose, Calif. (US) | ||
| Assigned to Panasonic Corporation, Osaka (Japan) | ||
| Filed on Aug. 06, 2007, as Appl. No. 11/890,597. | ||
| Claims priority of provisional application 60/836612, filed on Aug. 08, 2006. | ||
| Prior Publication US 2008/0055007 A1, Mar. 06, 2008 | ||
| Int. Cl. H03L 7/00 (2006.01) | ||
| U.S. Cl. 331—16 [331/34; 331/177 R] | 12 Claims |
| 1. A circuit including a feedback loop for tracking an input signal having modulation applied thereto, comprising:
a controlled oscillator producing an output signal;
a slow modulation circuit, including a loop filter, coupled to the input signal and to the controlled oscillator; and
a fast modulation circuit coupled to the input signal and to the controlled oscillator, the fast modulation circuit including
a compensation circuit configured to output an altered input signal, the compensation circuit referring to predetermined information
to alter the input signal in accordance with an output frequency characteristic of the controlled oscillator, thereby improving
linearity of the output signal.
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