Instantaneous frequency estimation using an adaptive short-time Fourier transform

Instantaneous frequency estimation is important in many applications, including FM demodulation. Time-frequency-based methods have been widely studied for IF estimation, particularly for low SNR, where they prove to be the most effective methods. We propose a new adaptive short-time Fourier transform algorithm, with chirping windows which is tailored for near-optimal time-frequency-based IF estimation. Extensive performance evaluations with both synthetic and real data demonstrate modest (1-2 dB) improvements in the threshold SNR over the best fixed-window STFTs. The computational cost of the new method is about ten times that of a fixed-window STFT.