Abstract: An apparatus for confirming a frequency measurement of a received signal includes a discrete Fourier transform (DFT) module for receiving a sampled digital signal. The DFT module is configured to analyze the received sampled digital signal, and output amplitude values at different frequency components. A threshold comparator is included for receiving the amplitude values of the frequency components and outputting a thresholded-amplitude value exceeding a predetermined threshold value. A frequency confirmation is provided based on the thresholded-amplitude value. The sampled digital signal is sampled at a sampling frequency of fs, and the DFT module is configured to analyze the received sampled digital signal at a frequency bandwidth that is equal to or less than fs. The frequency bandwidth is equal to the sampling frequency of fs, when the received sampled digital signal includes I and Q signals.

Abstract: An IFM receiver includes a hybrid for outputting I and Q signals from a received input signal; a first ADC for digitizing the I signal to produce a first digital signal at a sampling rate of 1/?, and a second ADC for digitizing the Q signal to produce a second digital signal at the same sampling rate. A processor is configured to (a) delay the first and second digital signals by at least one sample time of ?, (b) count the number of samples produced having predetermined phase shifts, and (c) determine the frequency of the received input signal, based on the number of samples having the predetermined phase shifts. The first and second ADCs are each 1-bit analog-to-digital converters. The predetermined phase shifts of 0°, 90°, ?90° and 180° are counted by the processor over a predetermined time interval.