Design And Implementation Of Testing System For 100mhz~400mhz Frequency-Hopping Filter

Frequency-hopping filter is widely used in large-scale communications systems, especially in military, such as aircraft, ship, tank and so on. There are many filters in frequency-hopping filter. The communication quality is associated with every filter's states. We can find problems in time by detecting the filter's states, so it's very important. In fact the frequency-hopping filter is constructed with many band-pass filters. The band pass filters are controlled by a switch array when hopping. So detecting the frequency-hopping filter equates to detecting the band-pass filters. It is especially important to detect the frequency performance in the pass band. Usually the frequency performance can be detected by frequency performance tester. But it's not fit for automation because of its cumbersome testing process. At the same time, it's not fit for system integration because of its large scale and high price.The most purpose of this subject is to design a automatic testing system of small scale, low price and fast speed for frequency-hopping filter. To filter, the most important indicators includes center frequency, insertion loss, VSWR, passband, ripple and shape factor etc. It is very hard to detect all those indicators and what we need is the state of the frequency filter. Insertion loss is one of the most important indicator. So we propose a proposal which only need to detect the insertion loss .This testing system is made up with SCM, DDS, low-pass filter, RF switch, detector and ADC. The principles of those parts, the problems and solutions are introduced. At last, the system achieved the desired results.