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US 6,608,529 B2Granted
Frequency synthesis apparatus, systems, and methods
AssigneeIntel Corporation
InventorLuiz M. Franca-Neto
Life of this patent
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Abstract
A frequency synthesizer, a multi-channel carrier generator, and a transceiver, as well as a method for generating a sub-carrier frequency are described. The frequency synthesizer includes two directly-connected, sequential chains of flip-flops, the first chain having N flip-flops, and the second chain having M flip-flops. The first chain of N flip-flops is clocked by a reference frequency input. Each chain provides a clocked output to an optional duty-cycle recovery circuit, which is in turn coupled to a frequency-update module. There is a sub-threshold low-pass filter included in the frequency-update module which feeds into an oscillator, providing, in turn, the generated frequency as an input to the second chain of M flip-flops, and a sub-carrier frequency output.
Claims29
A frequency synthesizer, comprising:
- a first directly-connected sequential chain of N flip-flops including a reference frequency input and a clocked output;
- a second directly-connected sequential chain of M flip-flops including a generated frequency input and a clocked output;
- a frequency-update module having a reference signal input and a comparison signal input coupled to the clocked outputs of the first and second directly-connected sequential chains of flip-flops, respectively, and a sub-threshold low-pass filter;
- and
- an oscillator coupled to the sub-threshold low-pass filter and the generated frequency input.
2 more elements
A multi-channel carrier generator, comprising:
- a first frequency synthesizer having a common reference frequency input, comprising:
- a first directly-connected sequential chain of N flip-flops coupled to the common reference frequency input and a clocked output;
- a second directly-connected sequential chain of M flip-flops including a generated frequency input and a clocked output;
- a frequency-update module having a reference signal input and a comparison signal input coupled to the clocked outputs of the first and second directly-connected sequential chains of flip-flops, respectively, and a sub-threshold low-pass filter;
- and
- an oscillator coupled to the sub-threshold low-pass filter and the generated frequency input;
- and
- a second frequency synthesizer coupled to the common reference frequency input, comprising:
- a first directly-connected sequential chain of N flip-flops coupled to the common reference frequency input and a clocked output;
- a second directly-connected sequential chain of O flip-flops including a generated frequency input and a clocked output;
- a frequency-update module having a reference signal input and a comparison signal input coupled to the clocked outputs of the first and second directly-connected sequential chains of flip-flops, respectively, and a sub-threshold low-pass filter;
- and
- an oscillator coupled to the sub-threshold low-pass filter and the generated frequency input.
10 more elements
A transceiver, comprising:
- a transmitter;
- a receiver;
- and
- a multi-channel carrier generator coupled to the transmitter and receiver, comprising:
- a first frequency synthesizer having a common reference frequency input, comprising:
- a first directly-connected sequential chain of N flip-flops coupled to the common reference frequency input and a clocked output;
- a second directly-connected sequential chain of M flip-flops including a generated frequency input and a clocked output;
- a frequency-update module having a reference signal input and a comparison signal input coupled to the clocked outputs of the first and second directly-connected sequential chains of flip-flops, respectively, and a sub-threshold low-pass filter;
- and
- an oscillator coupled to the sub-threshold low-pass filter and the generated frequency input;
- and
- a second frequency synthesizer coupled to the common reference frequency input, comprising:
- a first directly-connected sequential chain of N flip-flops coupled to the common reference frequency input and a clocked output;
- a second directly-connected sequential chain of O flip-flops including a generated frequency input and a clocked output;
- a frequency-update module having a reference signal input and a comparison signal input coupled to the clocked outputs of the first and second directly-connected sequential chains of flip-flops, respectively, and a sub-threshold low-pass filter;
- and
- an oscillator coupled to the sub-threshold low-pass filter and the generated frequency input.
14 more elements
A method of generating a sub-carrier frequency, comprising:
- providing a reference frequency to the reference frequency input of a first directly-connected sequential chain of N flip-flops;
- feeding back the sub-carrier frequency from an oscillator to a second directly-connected sequential chain of M flip-flops;
- providing a clocked output of the first directly-connected sequential chain of N flip-flops as a reference signal input to a phase detector, and a clocked output of the second directly-connected sequential chain of M flip-flops as a comparison signal input to the phase detector to produce a phase output including high-frequency signal components;
- filtering out some portion of the high frequency signal components from the phase output using a sub-threshold low-pass filter to produce a filtered phase output;
- and
- providing the filtered phase output to the oscillator.
3 more elements
Dependencies are inferred from the claim text.