Photonics-assisted two-step microwave frequency measurement based on frequency-to-time mapping

Taking the advantages of photonic technology, such as large bandwidth, good tunability, and immunity to electromagnetic interference, a two-step high-accuracy photonics-assisted microwave frequency measurement method based on frequency-to-time mapping is proposed. Through high-speed optical frequency sweeping and optical filtering, the method maps different signal frequencies to time-domain pulses at different time and can measure multiple frequencies simultaneously. With the assistance of ultra-high-speed frequency sweeping and frequency-to-time mapping, the fast coarse identification of multiple different signal frequencies in the wide bandwidth range of 12 GHz is realized, and the measurement accuracy is better than 100 MHz. After the signal frequency is coarsely determined, low-speed frequency sweeping and frequency-to-time mapping are employed to realize accurate identification of the signal frequency within a small bandwidth. When the sweep rate is 2 and 0.2 GHz/μs, the accuracy of accurate measurement is better than 30 and 20 MHz respectively. Through the two-step measurement, high-accuracy frequency measurement can be achieved in a large bandwidth range while greatly reducing the microwave frequency measurement time.