科研之友
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摘要
To meet the boot-strap self-test requirements of electromagnetic prospecting systems, the characteristics of self-test signals of commonly used geophysical instruments and measurement systems are analyzed. Through doing comparison and analysis on existing mechanisms, a novel method is proposed with low-power consumption, high precision, as well as easy realization. A set of implementation circuit is designed and simulated. The circuit is shown to have a strong stability on the basis of Bode and Nyquist diagrams. The simulation and test results show that a self-test pulse with a range of 20 mu V similar to 2 V amplitude and 1 Hz similar to 100 kHz frequency can be generated through switches. And the signal frequency stabilizes at 1%; phase stability is no more than 1. 5% through repeated test, and amplitude error can be optimized to less than 1%. Using the stable harmonic component of the self-test pulse signal, a response in wider band of the measurement system can be obtained. The practical application demonstrates that the boot self test model has a power consumption less than 0. 3 Watt; and an amplitude between 20 mu V and 2 V, and frequency range of 1 Hz similar to 100 kHz. This is consistent with the simulation. The self test model is applied to a monitoring system. The model has the advantages of stable performance, convenient operation, low cost, and easy-to-design. It can improve present self-test models.
