Carrier frequency offset compensation circuit and process for a communications receiver
AssigneeSTMicroelectronics International N.V.
InventorGagan Midha
Life of this patent
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Abstract
A frequency demodulated signal includes a frequency modulation in time that is shifted by a DC level corresponding to a carrier frequency offset. A number of different frequency offsets are applied to the frequency demodulated signal to generate a corresponding number of offset frequency demodulated signals. Each offset frequency demodulated signal is correlated against a reference signal and a determination is made as to which correlation produces a highest correlation value. One offset frequency demodulated signal of the number of offset frequency demodulated signals is then selected for output as an offset corrected frequency demodulated signal. The selected signal is the one having the highest correlation value.
Claims14
A circuit, comprising:
- an input configured to receive a frequency demodulated signal comprising a frequency modulation in time that is shifted by a direct current (DC) level corresponding to a carrier frequency offset;
- a plurality of frequency shifting circuits configured to apply a corresponding plurality of frequency offsets to the frequency demodulated signal to generate a corresponding plurality of offset frequency demodulated signals;
- a correlation circuit configured to correlate each offset frequency demodulated signal of the plurality of offset frequency demodulated signals against a reference signal;
- a maximum correlation detection circuit configured to determine which correlation performed by the correlation circuit produces a highest correlation value and generate a selection signal identifying one offset frequency demodulated signal of the plurality of offset frequency demodulated signals which has said highest correlation value;
- and
- a multiplexer circuit configured to receive the plurality of offset frequency demodulated signals, said multiplexer controlled by the selection signal to pass said one offset frequency demodulated signal of the plurality of offset frequency demodulated signals having the highest correlation value for output as an offset corrected frequency demodulated signal.
A method, comprising:
- receiving a frequency demodulated signal comprising a frequency modulation in time that is shifted by a direct current (DC) level corresponding to a carrier frequency offset;
- applying a corresponding plurality of frequency offsets to the frequency demodulated signal to generate a corresponding plurality of offset frequency demodulated signals;
- correlating each offset frequency demodulated signal of the plurality of offset frequency demodulated signals against a reference signal;
- determining which correlation produces a highest correlation value;
- and
- selecting one offset frequency demodulated signal of the plurality of offset frequency demodulated signals which has the highest correlation value for output as an offset corrected frequency demodulated signal.
Dependencies are inferred from the claim text.