In modern complex battlefield environment, it is important to obtain the frequency spectrum precisely. We propose an operational method of instantaneous frequency measurement (IFM) assisted by photonics, which can achieve high precision based on stimulated Brillouin scattering (SBS), giving the credit to the narrow linewidth of gain spectrum of SBS. By setting the scanning frequency, the amplitude comparison function (ACF) can be formed in the narrow lineband based on SBS effect. And the measurement of full frequency band is realized through a reference signal, the measured frequency range is limited only by photoelectric device. Estimation of multiple RFs can also be achieved with a resolution of 250MHz. In the numerical simulation, the average measurement error less than 1MHz is achieved in this scheme.
This paper proposes a channelized receiver based on microwave photonic, the system generated two coherent optical frequency comb with different free spectral ranges. By adjusting carrier frequency, a different frequency interval is formed between the local frequency comb and the optical comb modulating the signal to be measured. After the two optical combs pass through the optical demultiplexer respectively, the corresponding channel is beat frequency and the heterodyne detection is realized by converting the signal to intermediate frequency.The scheme proposed in this paper realizes the measurement frequency range of 2GHz~18GHz, has the instantaneous bandwidth of more than 7GHz, and the average error is less than 50MHz