4957D/E/F Microwave Analyzer Quick Start Guide
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press [OK] to complete the input.
Min
Press [Amplitude] → [Min Scale], enter the min value with the numeric keys, and
press [OK] to complete the input.
2) Auto Scale
With auto scale function of this mode, the display range of the measured power can be
automatically adjusted in the following steps:
Press [Amplitude] → [Auto Scale].
7. Setting the relative measurement function
The relative measurement function reflects the changes of the power that has been set
as the reference signal. The readings of the power value changes are expressed in dB
and % respectively. When the relative measurement switch is turned on, the analyzer will
measure and store the current power level, while the power measurement will display a
power level relative to the saved value. Follow these steps:
Press [Amplitude] → [Relative Off / On], and switch to [Relative Off / On].
When the relative measurement function is turned on, the power readings will be shown
as 0 dB and 100%. For example, to measure a signal with a power of 5 dBm, when the
relative measurement function is turned on and the signal power is reduced to 2 dBm, the
power readings at this time are -3 dB and 50%.
8. Setting the offset function
When the power of the measured DUT is greater than the maximum power that the
instrument can measure, the measured power can be reduced within the normal
measurement range by connecting an attenuator. The power offset function allows for
setting offset values to offset attenuation values or cable losses for added attenuators or
connecting cables. It also allows for setting power offsets for gains of added amplifiers.
Positive values can compensate losses and negative values can compensate gains. For
example, if a 10 dB attenuator is added to protect the probe, to avoid excessive input
power, the offset value is set to 10 dB. At this time, the power reading of the analyzer is
the actual reading. If an amplifier with a gain of 10dB is added to the measuring end, the
offset value is set to -10 dB, and then the power reading of the analyzer is the actual
reading. The function settings are as follows:
Press [Amplitude] → [Offset Off / On] to enable the power offset function.
9. Setting averaging
The averaging function is generally used to measure low-power signals or signals close
to noise power. It can smooth traces to reduce the influence of random noise on the
measurement and improve measurement accuracy, but at the same time it will reduce
measuring speed. The times of averaging determine the times for reading averaging. The
more averaging times, the more the noise will be reduced. The times of averaging are
displayed at the upper left corner of the measurement data display zone. The times of
averaging can be set between 1 ~ 999. Setting the averaging times will not affect the
calibration accuracy. The averaging function is set as follows:
Press [BW] → [Ava Off / On] to turn on the averaging function, with the times set to 16 by
default. You can also enter the desired averaging times with the numeric keys, and press
[OK] to complete.
3.7 Testing Skills
The test
steps of several test formats have been described in detail above, and now we’ll
introduce some common skills during the measurement below.
