Wireless Passive High-Temperature Sensor Readout System for Rotational-Speed Measurement

Rotational-speed measurement in harsh environments is an important topic. However, the high rotation results in rapid frequency variations in the signals of a sensor and changes in physical properties under extreme thermal circumstances cause significant difficulties in reading signals. To address this problem, we adopt wireless passive measurement methods to design a special characteristic signal circuit module that achieves precise measurement of rotational speed at high temperatures. The sensor and the readout system include a variable frequency source, a readout antenna, and a radio frequency demodulation circuit. Herein, a demodulation detector of the signal conversion circuit is designed and used in the envelope detection module of the single sideband demodulation method. In addition, a conversion circuit test platform for high-temperature environment sensor signal is developed. From the testing, the output signal demodulation of the sensor was observed under a maximum temperature of 700°C with error less than 0.12%. The new sensor and measurement method do not require physical leads and achieve wireless noncontact accurate measurement of rotational speed at high temperature.

Monopulse radar tracking by range and angular coordinates with a broadband sounding signal.

A block diagram of the receiving part of a monopulse radar tracking by range and angular coordinates with a broadband sounding signal is presented. The features of correlation processing of a broadband linear-frequency-modulated signal with full frequency demodulation and algorithms for estimating coordinates are considered. A comparative analysis of the results of calculating errors in measuring the coordinates of air targets in short-range radars using narrow-band and broadband signals and different viewing angles is carried out.