A.V. Filatov, A.V. Ubaychin, N.O. Zhukov

A two-channel radiometer with automatic settings of zero balance was considered. A combined pulse modulation (amplitude and pulse-duration) is being used in scheme. Algorithm of the follow-up system of auto regulation of the zero balance was developed by changing the duration of the signal. A linear transfer characteristic of the system was obtained. This characteristic lets indirectly determine antenna signal without conversions of signals in low frequency tract by the duration of pulse reference noise signal generator. A two-channel zero radiometer uses two alternately operating receivers that allows measuring the antenna signal without passes. The results of experimental tests were received and obtained. The aim was to check the radiometer on fluctuation sensibility throughout the dynamic range, temperature and long time stability. Tests of zero two-channel radiometer on the characteristics stability were being held in comparison with classic modulation radiometer. Temperature stability was increased by 22 times, long time stability was increased by 2.2 times. Using of synchronously working two channels have led to decrease of threshold for detecting a signal and improving the dynamic properties of the system. Measurements sensitivity has increased by 21/2. Dynamic characteristics of two-channel radiometer are twice better then single-channel scheme.