Simulation and optimization study of signal sampling for double-interface guided wave radar level gauge based on similar equivalent sampling

Guided wave radar level gauges are known for their high measurement accuracy, low maintenance costs, and high reliability, making them suitable for challenging conditions such as high temperature and pressure. In order to use guided wave radar for measuring oil, water, and gas interfaces, the transmitted signal employs high-frequency pulse signals with extremely narrow pulse width. By combining the similar equivalent sampling method and using a pair of positive and negative symmetric sampling pulses to control the sampling gate switch, the high-frequency radar signal is extended into a low-frequency signal that can be collected by a microcontroller. The four-diode bridge sampling circuit utilizes HSMS- 285P, resulting in a significant reduction in the output signal noise of the circuit. Simulation results indicate that this circuit is applicable for a double-interface measurement system.