The Frequency Response Analyzer (FRA) is a microcomputer-based instrument that produces Bode (frequency-response) plots of both magnitude and phase of one-port or two-port networks. For one-port networks, the FRA is a RLC meter which can measure series resistance for inductors and capacitors.

The FRA project is on-going. At present, the FRA prototype can do frequency sweeps. It generates a frequency and amplitude programmable sinewave, which drives a power op-amp, which can source several amperes. The output voltage and current are sensed. The measurement side of the FRA includes an input mux and a PGA. The mux is used to autocalibrate the measurement subsystem and to switch in generator output current or voltage, or the output port of a two-port network. Sinewave amplitude is detected with a synchronous peak detector. This non-averaging approach speeds up low-frequency measurements considerably. The phase detector is an XOR gate followed by filtering and input to an ADC.

 If you are interested in participating in this project, contact dennis@innovatia.com.