The AD5934 is a high precision impedance converter system solution that combines an on-board frequency generator with a 12-bit， 250 kSPS， analog-to-digital converter （ADC）。 The frequency generator allows an external complex impedance to be excited with a known frequency. The response signal from the impedance is sampled by the on-board ADC and a discrete Fourier transform （DFT） is processed by an on-board DSP engine. The DFT algorithm returns a real （R） and imaginary （I） data-word at each output frequency. Once calibrated， the magnitude of the impedance and relative phase of the impedance at each frequency point along the sweep is easily calculated using the following two equations： Magnitude = 2 2 R + I Phase = tan?1（I/R） A similar device， available from Analog Devices， Inc.， is the AD5933， which is a 2.7 V to 5.5 V， 1 MSPS， 12-bit impedance converter， with an internal temperature sensor， available in a 16-lead SSOP.