3M ScanEM-QC CTK019, Руководство пользователя

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11
Operation as a Probe
Basics
The 3M
™
ScanEM-QC Electromagnetic Near-Field Probe provides AC and
DC outputs to virtually any piece of test equipment: spectrum analyzer,
oscilloscope, frequency counter or multimeter. Output is provided via an
SMB connector and the supplied cable. For some types of test equipment
you may need to use additional adaptors (typically, BNC-to-N or BNC-to-
banana plugs). Such adaptors are widely available.
The DC voltage that the ScanEM-QC Electromagnetic Near-Field Probe
provides has high output resistance—60 kOhms. While it doesn’t present
any problem when using the ScanEM-QC Probe with a multimeter with high
input impedance, connecting the ScanEM-QC Probe to a 50 Ohms input of
a spectrum analyzer limits the DC signal to a maximum of 2.5mV without
affecting the AC performance.
Always Set the Level Dial to zero When Using the ScanEM-QC as a
Probe
Î
When the Level dial is set to zero, it disables the ScanEM-QC Probe’s own
indication—the LEDs and the speaker—preventing any influence on the output
signal.
Do not load the ScanEM-QC Probe’s output with less than 50 Ohms load
(such as connecting it in parallel to the inputs of a spectrum analyzer and 50
Ohms input of an oscilloscope). The ScanEM-QC Probe’s performance will
be reduced.
Though the ScanEM-QC Probe has a wide dynamic range, a very strong
field may overload it. This may result in harmonic distortions of the output
signal. The overload condition can be clearly seen on the screen of a
spectrum analyzer or an oscilloscope. Should this occur, simply move the