Sensor impedance measurement

[Sradio]

Hey guys,

I'm currently doing the circuit for impedance measurment, particular for sensor use. Have anyone ever done this kind of circuit design? I have found an old paper dedicated in the measurement of complex impedance of incoming data. The question is, what topology do you guys use? I currently come up an idea, which is employing the VCO to generate a certain freq wave, and by using the cap to figure out the resonate freq, and that might be able to get input impedance from the equ as follow, R=1/(freq*Cap)

Hope to know more abt this topic, thanks in advance.
Attachment is the paper I found.

 

[kender]

There are impedance analyzers on a chip AD5933 and AD5934. They can analyze up to 100kHz and 250kHz respectively. What frequency range do you want to analyze your impedances at? If it’s not a secret, what type of sensor do you want to analyze the impedance of?

BTW, here’s another good place to post your question: **broken link removed**.

 

[FvM]

Vectorial impedance measurement is used in electronics since ages. The said Analog chips are a very interesting solution for a specific frequency and impedance range, based on todays DSP tecnlogy. Basically you would be able to design vectorial impedance measurement for any frequency up to GHz (with respective effort). But the topic can hardly be discussed without a clue of intended frequency and impedance range and required resolution.