PLL-based frequency discriminator using the loop filter as an estimator

In this paper we present a new phase-locked-loop-based frequency discriminator architecture that performs both A/D conversion and frequency demodulation. In addition, the loop filter is designed as a linear estimator. Two forms of linear estimators are investigated. Simulation results show that for a minimum shift key signal at 400 MHz IF, the proposed frequency discriminator achieves an SNR improvement of up to 5 dB over a large variety of noise/fading conditions.