Installation guide

9
Instructions
3. Press {Zeroing ►} to perform the Internal or External Zeroing if necessary (see
Figure 15).
Internal Zeroing
Internal zeroing uses an electronic switch to isolate the power sensor bulkhead
from the internal measurement circuitry during the procedure, thereby allowing the
sensor to be physically connected to an active RF source when internally zeroing.
Therefore, you do not need to disconnect the RF source or power off the external
source during an internal zero procedure. This feature makes internal zeroing more
convenient, but you may only use internal zeroing if zero set (Internal) is within the
application requirements.
External Zeroing
In external zeroing, the sensor does not utilize the electronic switch to isolate
the measurement circuitry from the bulkhead. In this case, the RF power must be
removed from the bulkhead either by turning the source off or physically removing
it from the sensor during the external zero procedure. External zeroing generally
has better zero set performance. The INT or EXT zeroing selection should be made
based on the measurement needs.
By default, internal zeroing is performed by the fi rmware when the USB sensor is
connected to N9340A HHSA.
Figure 15 External and Internal Zeroing are performed to reduce the zero offset
and noise impact in order to measure power accurately