Frequency Response Analyzer


The Frequency Response Analyzer (FRA) is housed in the NaMPET Lab (WL‐110) for measurement and evaluation of dynamic characteristics of Power converters, sensors and electronic amplifier circuits. This instrument obtains the frequency response of the test circuit and evaluates the complex gain in polar form (magnitude and phase). The input excitation in a sinusoidal voltage, the frequency of which is swept over the range of interest and the output is converted to an equivalent voltage signal and read in by the instrument. The associated software interface allows plotting of relevant bode plots, based on this input‐output behaviour, for further analysis of its dynamic behaviour.

This equipment from Solartron Analytical (Model no. 1255B) has a frequency sweep range of 10μHz – 1MHz with a programmable excitation amplitude of 0 to 3 V rms (sensitivity 100μV), being capable of sourcing a maximum current (bipolar) of 100 mA. It has two independent analyzers in parallel allowing simultaneous test of two circuits. With a standard interface impedance of 50Ω

This equipment has been used for determining the actual dynamic behaviour of a physical circuit and the test results are used for either validating or improving the analytical dynamic model of a system or to derive one, in black‐box situations. The test results shown are for a motor drive for aerospace applications, used by the Aerospace Engineering Department. This instrument has also been used to determine the cut‐off frequencies of sensor circuits used for online voltage feedback in power applications.


NaMPET Lab, Department of Electrical Engineering,
IIT Kanpur


Prof.Parthasarathi Sensarma

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Fig: 1