Abstract:

In view of the adverse effects brought by the noise in mine on the signal detection, we put forward a digital phase sensitive detection optimization algorithm which does not need external same frequency reference signal. And from the simulation experiment system of PED, effectiveness of digital phase sensitive detection algorithm has been verified on the receiving part. The algorithm samples measue signal many cycles, then the calculated value is got by multiply accumulating and averaging the number of sampling and reference value which is stored in array. After calculating the cophase and orthogonal component, we get the result of signal amplitude.Supposing that the standard of receiving signal in PED receiving system is judged by signal dependency over 0. 6
in the environment, the least SNR received by the system is -58 dB. The method can improve accuracy rating of receiving useful signal to some extent. Furthermore, the receiving instrument is made more miniaturizing and is convenient to the benefit of the algorithm.

Key words: personal emergency device(PED), phase sensitive detection, filtering, A / D conversion