Cables or other metal (antenna-like) structures can couple to sources of common mode currents and end up radiating, causing product failures during compliance testing. During the troubleshooting process, it would be helpful to determine the resonant frequency of these cables or structures to confirm they are the source of certain harmonic signals. Often, as you probe a circuit board or measure the emissions from a product, you may notice a group of individual harmonics, which peak in amplitude over a given frequency range. This may indicate that a metal structure or cable is resonant at these peak frequencies. By analyzing whether the cable or structure is a halfwave or quarter-wave long, it might be identified and remediated in some way. To do so, you will need to convert the frequency into a corresponding quarteror half-wavelength.

Inspec keywords: antenna testing; frequency estimation; telecommunication cables; failure analysis

Other keywords: compliance testing; common mode current; frequency conversion; resonant structure measurement; circuit board; resonant frequency determination; cable structure; harmonic signals; troubleshooting process; product failure

Subjects: Reliability; Wires and cables; Single antennas; Other topics in statistics