Precise Multiple Frequency Identification Based on Frequency-to-Time Mapping and Cross-Correlation

We propose and demonstrate a microwave frequency identification system based on frequency-to-time mapping (FTTM) and cross-correlation. The unknown microwave signals and the bidirectional chirped microwave probe signal are mixed by using a dual-drive Mach-Zehnder modulator. The mixing products are equivalently selected by a dispersion induced photonic filter and converted into electrical pulses in time domain. The unknown frequency is measured by calculating the time interval of the pulses. Moreover, a scheme based on cross-correlation is proposed to eliminate the noise interference for the pulse position acquisition. Experimentally, single and multiple frequency identification from 2–14 GHz is successfully demonstrated, and the measured frequency errors are less than ±3 MHz.