Frequency synthesizer, coupled divide-by-N circuit, current-reuse multiply-by-M circuit
AssigneeNational Taiwan University
InventorsChe-Wei Fan, Shen-Iuan Liu
Life of this patent
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Abstract
A frequency synthesizer is provided in the present invention. The frequency synthesizer includes a single phase-locked loop having a reference frequency signal input, a first output, a second output and a pair of divide-by-N circuits coupled with each other and electrically connected to the second output; a multiply-by-M circuit having a first input electrically connected to the first output and a third output; and a combination of a buffer and a mixer having a second input electrically connected to the second output and a third input electrically connected to the third output generating a frequency signal output.
Claims11
A frequency synthesizer, comprising:
- a single phase-locked loop having a reference frequency signal input, a first output, a second output and a pair of divide-by-N circuits coupled with each other and electrically connected to the second output;
- a multiply-by-M circuit having a first input electrically connected to the first output and a third output;
- a combination of a buffer and a mixer having a second input electrically connected to the second output and a third input electrically connected to the third output generating a frequency signal output;
- and
- a plurality of inverters connected to each of the pair of divide-by-N circuits so as to reduce a mismatch generated therefrom.
A frequency synthesizer, comprising:
- a single phase-locked loop having a reference frequency signal input, a first output, a second output and a pair of voltage controlled oscillators (VCOs) coupled with each other and electrically connected to the first output, wherein each VCO has N circuit cells, each of which has a digital multiband selective load circuit selecting a band among different oscillating bands;
- a multiply-by-M circuit having a first input electrically connected to the first output and a third output;
- and
- a combination of a buffer and a mixer having a second input electrically connected to the second output and a third input electrically connected to the third output, and generating a frequency signal output.
A frequency synthesizer, comprising:
- a single phase-locked loop having a reference frequency signal input, a first output and a second output, and including:
- a frequency detecting circuit having the reference frequency signal input and a feedback frequency input, and generating a detecting signal output:
- a voltage controlled oscillator (VCO) having a detecting signal input electrically connected to the detecting signal output, a third output and the first output, wherein the pair of divide-by-N circuits further comprise a first input electrically connected to the third output and a fourth output;
- and
- a divide-by-P circuit having a second input electrically connected to the fourth output and a feedback frequency output electrically connected to the feedback frequency input,
- a current-reuse single multiply-by-M circuit having a third input electrically connected to the first output and a fifth output, wherein the multiply-by-M circuit comprises a first sub-circuit and a second sub-circuit driven by the same current;
- and
- a combination of a buffer and a mixer having a fourth input electrically connected to the second output and a fifth input electrically connected with the fifth output generating a frequency signal output.
Dependencies are inferred from the claim text.