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Measurements >> RF Measurements >> Simple help needed for resonance measurement
https://designers-guide.org/forum/YaBB.pl?num=1424333424

Message started by orbitcoms on Feb 19^th, 2015, 12:10am

Title: Simple help needed for resonance measurement
Post by orbitcoms on Feb 19^th, 2015, 12:10am

I need to measure resonant frequency of a small RFID antenna. The device has L = 10mH, RDC = 165 Ohms and Q > 25.
When I attempt to measure the resonant frequency using my sig gen and scope with 10x probe, the measurement system (I think the capacitance of the scope probe or scope input) is changing the frequency.
In my old RF days we used to couple into Tanks using a very low value capacitor. I do also have a Spectrum analyzer with tracking gen and couplers if this helps.
Would someone mind explaining an effective setup I could use to measure this properly. I need the resonance frequency to work out size of Caps on the PCB to resonate with the inductor at 125 kHz.
Thanks in advance
David
engineering@orbitcoms.com