US 12,047,210 B2 · Demodulating frequency-modulated signals

Abstract

A method of, and apparatus for, demodulating a frequency-modulated signal. The method comprises: for each of a plurality of templates, performing a respective cross-correlation operation between the template and data representative of the frequency-modulated signal, each template comprising data representative of a signal that is frequency-modulated with predetermined preamble data using a different respective modulation index; generating frequency-offset data from one or more of the cross-correlation operations, the frequency-offset data being representative of a difference between a reference frequency and a carrier frequency of the frequency-modulated signal; determining a respective peak correlation-coefficient value from each of the cross-correlation operations; identifying a highest peak correlation-coefficient value in the determined peak correlation-coefficient values; determining a modulation index estimate in dependence on which template produced the highest peak correlation-coefficient value; and using the frequency-offset data and the modulation index estimate to demodulate at least a portion of the frequency-modulated signal.

Claims20

Dependent claims

A method of demodulating a frequency-modulated signal, the method comprising:

for each of a plurality of templates, performing a respective cross-correlation operation between the template and data representative of the frequency-modulated signal, wherein each template comprises data representative of a signal that is frequency-modulated with predetermined preamble data using a different respective modulation index;
generating frequency-offset data from one or more of the cross-correlation operations, the frequency-offset data being representative of a difference between a reference frequency and a carrier frequency of the frequency-modulated signal;
determining a respective peak correlation-coefficient value from each of the cross-correlation operations;
identifying a highest peak correlation-coefficient value in the determined peak correlation-coefficient values;
determining a modulation index estimate in dependence on which template produced the highest peak correlation-coefficient value;
and
using the frequency-offset data and the modulation index estimate to demodulate at least a portion of the frequency-modulated signal.

4 more elements

An apparatus for demodulating a frequency-modulated signal, the apparatus comprising:

a preamble correlator;
and
a signal demodulator,
wherein the preamble correlator is configured to:
perform, for each of a plurality of templates, a respective cross-correlation operation between the template and data representative of the frequency-modulated signal, wherein each template comprises data representative of a signal that is frequency-modulated with predetermined preamble data using a different respective modulation index;
generate frequency-offset data from one or more of the cross-correlation operations, the frequency-offset data being representative of a difference between a reference frequency and a carrier frequency of the frequency-modulated signal;
determine a respective peak correlation-coefficient value from each of the cross-correlation operations;
identify a highest peak correlation-coefficient value in the determined peak correlation-coefficient values;
and
determine a modulation index estimate in dependence on which template produced the highest peak correlation-coefficient value,
and wherein the signal demodulator is configured to:
use the frequency-offset data and the modulation index estimate to demodulate at least a portion of the frequency-modulated signal.

9 more elements

Dependencies are inferred from the claim text.

Demodulating frequency-modulated signals

Life of this patent

Demodulating frequency-modulated signals

Life of this patent

Abstract

Claims20