LeCroy AP034, Instruction Manual

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ISSUED: January 2000 AP034-OM-E Rev D
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When the AP034 Active Differential Probe is first connected to
the oscilloscope, the following message will appear:
“WARNING: Probe offset buttons are locked.” This alerts you
that offset control must be made through the oscilloscope, rather
than through the buttons located on the probe. It does not
indicate a failure in the probe or oscilloscope.
Note:
Correct display of scale factor with the ÷20
attenuator installed and correct operation of
probe offset require that software version 8.1 or
higher be loaded. Refer to the manual section
“Oscilloscope Software Compatibility” for
additional information.
AP034 USE WITH THE ADPPS POWER SUPPLY
The optional ADPPS Power Supply allows the AP034 Active
Differential Probe to be used with instruments that are not
equipped with the ProBus interface. When used with the ADPPS,
the AP034 must be terminated into 50
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input impedance is not 50
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between the ADPPS and the instrument input. If a coaxial
extension cable is used, the terminator should be located at the
instrument end of the cable. Note that the additional parasitic
losses of extension cables may reduce the usable bandwidth of
the system below the AP034 specification.
To prevent signal distortion, it is necessary to keep the AP034
output less than 400 mV at all times.
With the ProBus interface (see note on following page), the
oscilloscope O
FFSET
control actually controls the AP034 offset.
Without the ProBus, it is acceptable to use the oscilloscope to
position the waveform at high sensitivities, but it is a practice that
can lead to erroneous measurements when the probe output
exceeds ±400 mV. Therefore, when the ADPPS is used, it is
preferable to use the AP034 offset function to perform all
waveform positioning.
The AP034 offset allows you to measure signals up to 2.0 V
(1.6 V of offset plus 400 mV of output signal). With accessory
plug-on attenuators, the effective offset is increased, and input
signals of 20 V (÷10) or 40 V (÷20) may be viewed. The peak