Teledyne LeCroy WaveLink Differential Probe Series (8-13 GHz) - Manual (Page 30)

WaveLink Medium-Bandwidth (8-13 GHz) Differential Probe
Using the DC Blocking Adapter
The DC blocking adapter should be used when the common mode voltage of the circuit under test is
unknown or exceeds the maximum common mode voltage specified. Connect the each SMA input
lead to a DC block and the male side of the DC block to the SMA connector of the circuit under test.
When the DC blocking adapter is used, the probe is AC coupled and the LF cut-off frequency is
approximately 10 MHz.
NOTE: When using the DC Blocking Adapter set the Serial Data Analyzer’s offset to zero.
Probe Grounding
In most cases, when the common mode portion of the signal consists mainly of lower frequencies,
the probe does not need to be connected to the ground of the circuit under test. This minimizes the
effects of ground loop currents. Any signal corruption caused by not having the probe connected to
ground of the signal under test is common to both inputs and is rejected by the differential operation
of the probe.
Positioning of the Input Leads
Normally the performance of the solder-in lead and positioner tip is not affected by the position of
the amplifier module. They can be mounted straight upright or on an angle. However, when it is
necessary to mount the module parallel to the board, the maximum performance is obtained when
the + sign (printed near the positive input on both the SI lead and the positioner tip) is upward facing.
NOTE: The flexible cable connecting the input tip to the amplifier module is reasonably insensitive to
placement, but can be affected by large signal emitters on the device under test, so avoid placing it
near these types of signals
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