| US 7,545,847 B2 | ||
| Frequency synthesizer applied to frequency hopping system | ||
| Chi-Tung Chang, Taipei (Taiwan); Chih-Hao Lai, Taipei (Taiwan); and Chieh-Tsao Hwang, Taipei (Taiwan) | ||
| Assigned to Alcor Micro, Corp., Nangang District, Taipei (Taiwan) | ||
| Filed on Jul. 06, 2007, as Appl. No. 11/773,963. | ||
| Claims priority of application No. 96117102 A (TW), filed on May 14, 2007. | ||
| Prior Publication US 2008/0285625 A1, Nov. 20, 2008 | ||
| Int. Cl. H04B 1/38 (2006.01) | ||
| U.S. Cl. 375—133 [331/4; 375/260] | 19 Claims |
| 1. A frequency synthesizer applied to a frequency hopping system comprising:
a voltage controlled oscillator (VCO) for generating an oscillating frequency according to a voltage control signal;
a phase lock loop system comprising a first frequency divider, the phase lock loop system being used for dividing the oscillating
frequency by a first even number with the first frequency divider to generate a first dividing signal and generating the voltage
control signal according to the first dividing signal;
a second frequency divider connecting to the VCO, for dividing the oscillating frequency by a second even number to generate
a second dividing signal and a third dividing signal;
a first single-side-band mixer (SSB mixer) connecting to the second frequency divider, for mixing the second dividing signal
and the third dividing signal to generate a first mixing signal;
a second SSB mixer connecting to the phase lock loop system and the first SSB mixer, for mixing the first mixing signal and
the first dividing signal to generate a second mixing signal according to a first band selection signal; and
a multiplexer connecting to the first SSB mixer and the second SSB mixer, for selecting the first mixing signal or the second
mixing signal to output according to a second band selection signal.
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