Research and Implementation for Key Technologies of Low Frequency Testers

The number of foreign professional digital tester designed for frequency characteristic is not large and the cost is too high as well. What´s more, homemade equipments are complex and bulky with low-accurate attenuator and no phase-frequency characteristic testing functions. To solve these problems, we studied on some key techniques such as the attenuation network design, phase difference measurement, control circuit and so on in low frequency digital frequency tester, two piece AD8302 chip combining with AD9854 is recommended to be a new phase difference polarity measurement techniques. Both system control and data processing could be achieved only by one piece of ARM9 S3C440 chip. When it is introduced into sweep tester, simplified circuit construction and more accurate attenuation as well as low producing cost. Finally, it is tested to be right with the help of system testing.