Application of Rectangular Pulse in Measurement of Analog Circuit´s Bandwidth

In order to improve the measurability for design of analog ICs and board-level analog systems, a method that uses rectangular pulse as actuator to achieve functional test for analog circuits was brought forward. With the analysis of frequency spectrum and some research on the relationship between analog circuits´ bandwidth and settling time, the idea of timing the rising time of response pulse signal so as to figure out the bandwidth of the circuit under test was put forward, an analog equivalent model was brought in and all test module was validated through experiments. Theoretical and empirical results show that the steeper rising edge a rectangular pulse has, the more accurate the test result is. In practice, we choose rectangular pulse circuit whose bandwidth is 3 to 5 times of that of the circuit under-test. This new method for bandwidth test of analog circuit will predigest the test process and improve the test precision when functional test is carried out. And compared with the traditional test methods, it´s more fitter for the dependable and measurable design of the analog circuit system.