Frequency Offset Correction
AssigneeST-Ericsson SA
InventorFranck Castex
Life of this patent
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Abstract
The invention relates to a radio-frequency circuit comprising: a control unit; and a phase-locked loop; wherein the control unit is arranged to determine an offset between an actual value of a reference frequency at the input to the loop on the basis of a measurement of the signal output from the filter of the loop, and a theoretical value of said frequency known to the control unit, via a relation known to the control unit, and to control a correction of said offset.
Claims12
1-9. (canceled)
A radio-frequency circuit comprising:
- an output operative to deliver a radio-frequency output signal;
- a control unit;
- a memory;
- an input operative to receive an input signal at a given reference frequency;
- and
- a phase-locked loop comprising
- a comparator having an output and a first input coupled to the radio-frequency circuit input;
- a filter having an output and an input coupled to the output of the comparator;
- a controlled frequency generator having an output coupled to the radio-frequency circuit output and an input coupled to the output of the filter;
- and
- wherein the comparator has a second input coupled to the output of the controlled frequency generator;
- wherein the memory is operative to store a relation between signal values at the filter output and reference frequency values, and wherein the control unit is arranged to determine an offset between an actual value of the reference frequency obtained on the basis of a measurement of the signal output from the filter and a theoretical value of said frequency known to the control unit, via the relation stored in the memory, and to control a correction of said offset.
A mobile telecommunications terminal comprising:
- a radio-frequency circuit comprising
- an output operative to deliver a radio-frequency output signal;
- a control unit;
- a memory;
- an input operative to receive an input signal at a given reference frequency;
- and
- a phase-locked loop comprising
- a comparator having an output and a first input coupled to the radio-frequency circuit input;
- a filter having an output and an input coupled to the output of the comparator;
- a controlled frequency generator having an output coupled to the radio-frequency circuit output and an input coupled to the output of the filter;
- and
- wherein the comparator has a second input coupled to the output of the controlled frequency generator;
- wherein the memory is operative to store a relation between signal values at the filter output and reference frequency values, and wherein the control unit is arranged to determine an offset between an actual value of the reference frequency obtained on the basis of a measurement of the signal output from the filter and a theoretical value of said frequency known to the control unit, via the relation stored in the memory, and to control a correction of said offset.
A method of controlling a radio-frequency circuit comprising an output operative to deliver a radio-frequency output signal, a control unit, a memory, an input operative to receive an input signal at a given reference frequency, and a phase-locked loop comprising a comparator having an output and a first input coupled to the radio-frequency circuit input, a filter having an output and an input coupled to the output of the comparator, a controlled frequency generator having an output coupled to the radio-frequency circuit output and an input coupled to the output of the filter, and wherein the comparator has a second input coupled to the output of the controlled frequency generator, wherein the memory is operative to store a relation between signal values at the filter output and reference frequency values, the method comprising steps performed by the control unit, the method steps comprising:
- measuring a signal value at the filter output;
- calculating an actual value for the reference frequency;
- comparing the calculated value to a theoretical value for the frequency;
- estimating an offset between the actual value of the reference frequency and the theoretical value for said frequency;
- and
- correcting the offset.
A computer-readable medium including program instruction operative to cause a control unit in a radio-frequency circuit comprising an output operative to deliver a radio-frequency output signal, the control unit, a memory, an input operative to receive an input signal at a given reference frequency, and a phase-locked loop comprising a comparator having an output and a first input coupled to the radio-frequency circuit input, a filter having an output and an input coupled to the output of the comparator, a controlled frequency generator having an output coupled to the radio-frequency circuit output and an input coupled to the output of the filter, and wherein the comparator has a second input coupled to the output of the controlled frequency generator, wherein the memory is operative to store a relation between signal values at the filter output and reference frequency values, to perform the steps of:
- measuring a signal value at the filter output;
- calculating an actual value for the reference frequency;
- comparing the calculated value to a theoretical value for the frequency;
- estimating an offset between the actual value of the reference frequency and the theoretical value for said frequency;
- and
- correcting the offset.
Dependencies are inferred from the claim text.