| CPC H03K 5/00006 (2013.01) [H03D 7/00 (2013.01); H03K 2005/00286 (2013.01)] | 16 Claims |
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1. A synthesizer comprising:
an oscillator configured to output an oscillator output signal;
a coarse frequency adjustment circuit for the oscillator and a fine adjustment circuit for the oscillator;
a frequency multiplier for receiving a first analog signal, wherein the frequency multiplier is configured to multiply the first analog signal for generating a multiplied output signal;
a first mixing stage having two input ports connected with the frequency multiplier and the oscillator, respectively, the first mixing stage being configured to mix the multiplied output signal and an oscillator output signal of the oscillator, thereby generating an intermediate frequency signal;
a phase detector circuit configured to receive the intermediate frequency signal and a second analog signal, wherein the phase detector circuit is further configured to output a first control signal indicative of a phase difference between the second analog signal and the intermediate frequency signal; and
a second mixing stage configured to receive the second analog signal and the intermediate frequency signal, and configured to output a second control signal indicative of a phase difference between the second analog signal and the intermediate frequency signal;
wherein the coarse frequency adjustment circuit and a fine frequency adjustment circuit are controlled by the first control signal and second control signal, respectively, for generating the oscillator output signal of the oscillator.
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