A New Digital Frequency Detection Scheme

A new digital frequency detector for discriminating between the location of a noisy sinusoidal signal in one of two frequency bands is presented. Lower performance bounds of the detector are obtained. It is shown that the detector can discriminate between any two frequencies in a wide frequency band, and that these two frequencies can be arbitrarily close. Furthermore, correct decisions will be made in the presence of interference if maximum displacement of the zero crossings of the received signal due to interference satisfy certain loose bounds. For instance, correct decisions can be made even if there exists a spurious tone interference whose frequency and magnitude are close to those of the information signal. It is also shown that the peak of the impulse noises considered can be close to the peak of the information signal without causing a decision error. The detector can be easily implemented with a small number of standard digital circuits. It operates automatically and nonparametrically without requiring a priori knowledge of the statistics of the signal and interference.