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R&S FSH
Power Meter
Performing Pulse Power Measurements (R&S FSH-K29)
Operating Manual 1173.6275.12 - 30
149
Defining reference levels for pulse timing calculation
To calculate pulse timing parameters, like the rise and fall time of the pulse, you have
to define several reference levels. All reference levels are a percentage of the pulse
amplitude, either expressed in terms of power (Watt) or voltage (Volt).
The "Low Reference Power" and "High Reference Power" are required to calculate the
fall and rise times of the measured pulse. The "Low Reference Power" defines the
level at the start of the rising edge and the level at the end of the falling edge of the
pulse. The "High Reference Power" defines the level at end of the rising edge and the
level at the start of the falling edge.
The "Reference Power" is required to calculate the pulse width, its start time and its
stop time.
► Press the MEAS key.
► Press the "Ref Power Config" softkey.
► Define the reference levels as required.
You can always reset the reference levels to their default value with the "Set to
Default" menu item.
All the reference levels can be relative to the power or the voltage of the signal.
Depending on this selection, different measurement points are being analyzed, so the
results may be different.
► Press the MEAS key.
► Press the "Ref Power Config" softkey.
► Select either the "Power" or the "Voltage" menu item as the reference.
4.4.2.2 Selecting the Video Bandwidth
When you are using a wideband power sensor, you can change the video bandwidth
used for the measurement. The main effect of using a small video bandwidth is that it
reduces the displayed inherent noise.
Using a small video bandwidth thus increases the measurement sensitivity and allows
you to accurately determine the pulse peak power even for weak pulses. Reducing the
video bandwidth also increases the trigger sensitivity of the power sensor.
Note however that the video bandwidth should not be smaller than the RF bandwidth of
the measured signal. Otherwise, measurement results may become invalid.