Compensation for modulation distortion
First Claim
1. A phase locked loop with modulation distortion compensation system comprising:
- a phase detector, a loop filter including a tuning voltage output, a voltage controlled oscillator (VCO) configured to provide a modulated radio frequency signal, and a feedback divider with a modulation input all intercoupled as a phase locked loop;
a compensation function coupled to the tuning voltage output and configured to select a filter response from a plurality of filter responses, the filter response selected in accordance with a tuning voltage signal at the tuning voltage output; and
a filter configured to distort a modulation signal in accordance with the filter response and provide a distorted signal to the modulation input, the distorted signal used by the feedback divider in the phase locked loop to facilitate modulation of the VCO and effect compensation for modulation distortion resulting from the phase locked loop.
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Accused Products
Abstract
A modulation distortion compensation system for a phase locked loop 109 includes a compensation function (115) that is arranged to be coupled to a tuning voltage signal (117) corresponding to a tuning voltage from the phase locked loop and is configured to select a filter response from a plurality of filter responses, where the filter response corresponds to the tuning voltage. The distortion compensation system further includes a filter 224 that is configured to distort a modulation signal in accordance with the filter response and provide a distorted signal suitable for being coupled to a modulation input 211 of a feedback divider 209 included with the phase locked loop, wherein the distorted signal when used by the feedback divider will facilitate modulation and compensation of a radio frequency signal provided by the phase locked loop. Various environmental measurements in addition to the tuning voltage can also be used in selecting the filter response.
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Citations
20 Claims
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1. A phase locked loop with modulation distortion compensation system comprising:
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a phase detector, a loop filter including a tuning voltage output, a voltage controlled oscillator (VCO) configured to provide a modulated radio frequency signal, and a feedback divider with a modulation input all intercoupled as a phase locked loop;
a compensation function coupled to the tuning voltage output and configured to select a filter response from a plurality of filter responses, the filter response selected in accordance with a tuning voltage signal at the tuning voltage output; and
a filter configured to distort a modulation signal in accordance with the filter response and provide a distorted signal to the modulation input, the distorted signal used by the feedback divider in the phase locked loop to facilitate modulation of the VCO and effect compensation for modulation distortion resulting from the phase locked loop. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A modulation distortion compensation system for a phase locked loop, the modulation distortion compensation system comprising:
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a compensation function arranged to be coupled to a tuning voltage signal corresponding to a tuning voltage from the phase locked loop and configured to select a filter response from a plurality of filter responses, the filter response corresponding to the tuning voltage; and
a filter configured to distort a modulation signal in accordance with the filter response and provide a distorted signal suitable for being coupled to a modulation input of a feedback divider included with the phase locked loop, wherein the distorted signal when used by the feedback divider will facilitate modulation and compensation of a radio frequency signal provided by the phase locked loop. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A method of facilitating compensation for modulation distortion in a phase locked loop, the method comprising:
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providing a tuning voltage from the phase locked loop;
selecting, responsive to the tuning voltage, a filter response from a plurality of filter responses; and
filtering a modulation signal in accordance with the filter response to provide a distorted signal, the distorted signal suitable for modulation and compensation of a radio frequency signal provided by the phase locked loop. - View Dependent Claims (19, 20)
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Specification