Method And Apparatus For Identifying The Modulation Format Of A Received Signal
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Abstract
A method of identifying the modulation format of a received radio frequency (RF) signal from a plurality of modulation formats is described. The method comprises: (a) sampling the RF signal to generate sampled input data (520); (b) analysing at least first samples of the sampled input data to generate characteristic data (530); (c) comparing the characteristic data with stored information representing each of modulation formats to identify a most probable modulation format (550); and (d) outputting data representing the most probable modulation format (560). The modulation format can therefore be identified without requiring a sequential search until a match is found. In effect all of the modulation formats are being searched concurrently. This reduces the time required to identify the modulation format.
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Citations
18 Claims
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1-14. -14. (canceled)
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15. A synchronisation circuit for synchronising time with a received radio controlled clock signal, the synchronisation circuit comprising a receiver for a RF signal having a bandwidth including the transmission frequency of plurality of modulation formats, and wherein the plurality of formats includes at least two formats which have different transmission frequencies;
the receiver comprising;
an input connected to an aerial for receiving the RF signal; and
an analog-to-digital converter for sampling the RF signal at the frequency for a predetermined period of time to generate input data; and
a processor operative to;
(a) analyse at least one characteristic of the sampled input data to generate characteristic data;
(b) compare the characteristic data with information representing each of the plurality of modulation formats to identify a most probable modulation format from the plurality of modulation formats;
(c) output data representing the most probable modulation format;
wherein if in step (b) a single most probable modulation format cannot be identified, the processor is adapted to repeat steps (a) to (b) in sequence with input data generated for subsequent periods of time until a single most probable modulation format is identified;
wherein during said repetition of steps the processor is adapted to keep an accumulation of the characteristic data and use them in the identification of the most probable modulation format.- View Dependent Claims (16, 17, 18)
Specification