Simple frequency rate estimator

Frequency-rate estimation of a linearly frequency modulated signal is addressed. A simple estimation procedure that yields accurate estimates for moderately high signal-to-noise ratios is proposed. By transforming the original sequence into a sequence that is the phase data differenced twice, the problem becomes equivalent to estimating a constant in colored noise. Computer simulations verify the expected performance and show that the estimator achieves the Cramer-Rao bound for signal-to-noise ratios above 8 dB.