To direct against system noise and drift as well as background radiation influence on signal on space radiation measuring

this paper describes a singal detecting method ——numeral synchronous accumulation and demodulation. This method realized real time deducting background noise and improved measuring sensitivity

is of one order of magnitude. Meanwhile

constituent of electric system and key link are introduced. The compared measuring results between this metod and general method show that this method deduct backgrond noise about 80% especially small signal.