Study on TWACS modulated signal detecting methodbased on Σ-Δ modulation technique
Hou Zhen-xiu · Ha'erbin gongye daxue xuebao · 2005
There are two common methods to detect the modulated signal of TWACS (two way automatic communication system), the time-domain detecting method and time-frequency analysis. The traditional time-domain detecting method extracts few characters and has low counter-noise ability. The time-frequency analysis has complex calculation and costs high. According to this, the paper presents a new TWACS modulated signal detecting method based on sigma-delta modulation technique and proposes a valid time-domain detecting algorithm. The method adds the bit-stream codes outputted from sigma-delta modulator in modulating area, and then detecting the modulated signal by the difference of the bit-stream summation between nearby two cycles. After applying the method to power distribution network, shows that the method can detect the modulated signals well in a bad noise condition, which expends the application range of TWACS.