Frequency Discrimination Based on the Different Number of Peaks in Envelope Detection of Two-Tone CW Radar

A method for distinguishing the baseband signal for each frequency in two-tone radar is proposed by using the difference in the number of peaks of the envelope detected signal. The proposed method is based on the characteristic that the baseband signal for each frequency has a different number of peaks depending on the operating frequency at the fixed sampling frequency in data acquisition. The phase difference between the transmitting and receiving signals for each frequency can be obtained by using envelope detection of the baseband signals in the two-tone radar, and the proposed method can effectively match the phase difference and the operating frequency without using additional control and synchronization. This makes it simple to estimate the absolute range up to the maximum unambiguous range, corresponding to a phase difference of 2 $\pi$. Measurement results show that the absolute range using the two-tone radar with a frequency spacing of 150 MHz can detect the distance with an accuracy of 97.8% up to the maximum unambiguous range by using the proposed method.