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8) Press [Up] and [Down] to select the frequency point to be modified, and then press the [Edit] soft key to modify the
FDO at the current frequency point;
9) If the FDO at a certain frequency point needs to be deleted, it can be done through the [Delete] soft key;
10) The offset unit in FDO table can be logarithmic or linear of which the former is dB and the latter is %. Press [Edit
Unit] soft key to switch the unit.
When the FDO table is valid, the system displays the mark (1) in all measurement windows that use this channel.
If the frequency entered in the FDO table exceeds the frequency range defined in the sensor calibration table or FDO
table, the microwave power meter will use the highest or lowest frequency point in the corresponding table to set the
calibration factor and offset.
In practical application, if the frequency of the signal to be measured is different from the frequency point in the sensor
calibration table and the effective FDO table, the microwave power meter will use the linear interpolation method to
calculate the calibration factor and offset at that frequency point.
Fig. 3.14 shows the frequency offset edit window in which you can input the frequency point, offset value, etc.
Fig. 3.14 FDO edit window
3.10 Statistic Analysis of Power Measurement
The digital vector modulation method integrates amplitude modulation and phase modulation into a multi-level
structure to represent the bits of a data stream such as CDMA. These modulated signals and noises are very similar no
matter whether in the time domain or in the frequency domain, which leads to new measurement problems especially at
the transmitter end of a digital communication system. Since the peak-to-average power ratio of the modulated signal is
a complex function of the transmitted data rather than a function of the amplitude of the modulated signal, the original
definitions of modulation depth and index make no sense. The encoding and multiplexing methods used further
improve the similarity between the modulated signal and the noise. All these problems require the use of statistic
