Research on Signal Sampling of Guided Wave Radar Based on Similar Equivalent Sampling

In order to reduce measurement blind areas and improve measurement resolution, the transmitted signal of Guided Wave Radar Level Meter is a kind of high frequency pulse signal with extremely narrow pulse width. Therefore, the real-time signal sampling needs the high-speed AD chip with high performance, which is expensive, so the equivalent sampling method is often used to complete signal sampling at present. Because the equivalent sampling requires very narrow sampling pulse width and it is difficult to design, on the basis of equivalent sampling, the paper adopts a kind of similar equivalent sampling method to sample the signal of the Guided Wave Radar, stretches the transmitted signal and the reflected signal in the time domain, and makes the sampled signal easy to process by Micro Controller. The realization process is that a pair of positive and negative symmetrical sampling pulses control the sampling gate switch to complete the signal sampling. The simulation results and experimental results show that this sampling method can accurately measure the time difference between the transmitted pulse and the reflected pulse, and the sampled signal is easy to process. This method is a kind of high-precision and low-cost sampling method.