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Monitoring the Signals
You can monitor the signal on the traces or wires without contact with the
3M
™
ScanEM-C Electromagnetic Near-Field Probe. Connect the output of the
ScanEM-C Probe to an oscilloscope. Set the scope input coupling to AC. Bring
the tip of the ScanEM-C Probe to the trace or wire you need to test and observe
the waveform of the signal on the screen. Keep in mind that the waveform
of the radiated signal is different from that of the signal on the trace itself.
You won’t be able to measure distortion of the signal, nor will you be able to
precisely assess undershoot/overshoot of pulses. However you should be able
to reliably detect the signal, estimate its waveform, measure the frequency of
the signal, for example.—all without influencing the signal. This is especially
important for tuned circuits, crystals or high-impedance circuits—anywhere
where direct contact with the circuit disrupts its normal operation.
Locating Bad Connections
The ScanEM-C Probe can help in locating bad connections and broken
traces by showing sharply different radiation levels and patterns before and
after the connection in question.
Identifying Defective ICs and Other Components
Quite often it is difficult to identify a defective chip on a board by just
measuring the signals on its pins since the chip receives signals from the
other components. You can determine whether the IC is functional by
comparing its radiation pattern with a good IC on a similar working board.
Identifying Wires and Traces Carrying RF Signals
By monitoring radiation patterns of individual wires or traces in a live circuit,
you should be able to (1) follow the specific trace on a complex circuit board
or the wire in a cable assembly and (2) check whether that trace or wire is
connected properly. the ScanEM-C Probe can save you hours of guesswork.
