Patent ID: 7006797
Filing Date: 2006-02-28
Classification: H04B

Abstract:
1. An apparatus for determining frequency of a radio frequency signal comprising: a counter for counting zero amplitude transitions of a radio frequency signal in each of a plurality of time periods of identical duration; a first register for storing counted zero amplitude transitions for a selected one of the time periods; a second register for storing an accumulated count of zero amplitude transitions counted during a total counting time including the plurality of time periods; and comparing means for comparing counted zero amplitude transitions for each time period other than the selected time period with the counted zero amplitude transitions for the selected time period, the second register discarding the accumulated count if the counted zero amplitude transitions for any of the time periods other than the selected time period are different from the counted zero amplitude transitions for the selected time period by more than a quantization error, wherein the frequency of the radio frequency signal is indicated by the accumulated count stored in the second register when the total counting time ends.