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Question asked by KennyL on May 7, 2016
Latest reply on May 17, 2016 by KennyL

I recently bought one of these evaluation boards (new), which is an impedance measurement board. I downloaded the manual UG-364.pdf in order to figure out how to use this board. The manual contained no photo that specifically showed where to connect our arbitrary load impedance (to be measured). Eventually, I searched the internet and found a photo (attached) that indicates the load should be connected across a pair of terminals with a 'Z' label next to one of those terminals.


I haven't yet connected a load impedance to this evaluation board yet. I would kindly like to ask whether the load is meant to be connected at the location indicated in the image that I found on the internet.


Also, I understand that the AD5933EBZ evaluation board has a calibration procedure. But the procedure doesn't seem to address the effects of uncalibrated cables that we might use to connect to a capacitor load or an inductor load.


For many measurements, the capacitor load or an inductor load needs to be connected to the measurement device via relatively long lengths of cable. Does this evaluation board have a way to remove the effects of those connecting cables (wire).


If there is no facility for calibrating out the long lengths of connecting cable, then is there an Analog Devices impedance measurement evaluation board that handles that kind of thing?


I just want to add that the user guide UG-364 appears to be cryptic in some ways. For example, the evaluation board block diagram clearly shows an unknown impedance 'Z' connected between two operational amplifier stages (page 1). But, there is some seemingly contradictory information on page 6 that says "The sequence for performing a linear frequency sweep across a 200 kΩ resistive impedance connected across the VOUT and VIN pins". The contradiction is that VOUT and VIN pins are not between those operational amplifier stages.


Also, there is a sentence that doesn't make sense (looks incoherent) on page 20, namely "As an example, if a scaled clock frequency of 4 MHz must be applied to the external clock pin of the AD5933 to correctly analyze a 3 kHz signal that has already been established."


What would be nice in all user manuals is a true basic step-by-step example of how to use the device. Starting from beginning to end, rather than cryptic jigsaw puzzles that users need to try stitch together to work out how to take even a simple measurement with the device.


Thanks for all help and recommendations in advance.