| 摘要 |
A method of identifying frequency data for use in adjusting a frequency offset of a receiver is described. A signal is received, comprising a set of slots, at least one of the slots comprising a preamble portion and being transmitted at a predetermined transmission frequency. The predetermined frequency is within a known range of frequencies. The method comprises dividing the range of frequencies into a plurality of frequency bands. For each data item contained within the preamble portion, a magnitude of signal received within each frequency band is identified, and a plurality of pairs of frequency bands identified. For at least some of the plurality of pairs of frequency bands, a first signal magnitude identified for one of the frequency bands is subtracted from a second signal magnitude identified for the other frequency band, whereby to demodulate the signal within at least part of said preamble portion. The subtracted signal magnitudes are combined with output from an oscillator tuned to a fundamental of a period associated with the preamble portion. For each pair frequency bands, the signal magnitudes are accumulated over the preamble portion, whereby to identify frequency data for use in adjusting a frequency offset of the receiver. |
