Joint design of signal detection, demodulation classification, channel estimation and automatic gain control for multi speed HART

Traditionally, signal detection, demodulation classification, channel estimation and automatic gain control are designed separately and stabilization of those functions takes lots of symbols. In this paper, we propose a joint design of all those functions for multi-speed HART, which can adaptively demodulate HART FSK and HART C8PSK signals. According to the characteristics of HART channel and HART preamble, we employ sliding windowed DFT to estimate the power spectrum of HART preamble signal. Spectrum leakage and barrier effect, which are side effects of widowed DFT, are employed. In order to estimate the power at certain frequency lines fast and alleviate the interference of noise, we employ variable coefficient low pass filer. Simulations have shown that joint design of those functions can converge fast and work very well in low SNR.