Tektronix RSA6100A Series, Help Manual

Page: 274 / 415

GP Digital Modulation > Common Controls for GP
Digital Modulation Displays Freq & BW Tab
Freq & BW Tab
The Freq & BW tab speci fi es a group of settings that affect how measurements are made.
Freq & BW tab with nFSK or C4FM modulation type selected and Frequency Error readout enabled (Auto selected)
Freq & BW tab with SOQPSK modulation type selected and Frequency Offset enabled (Auto deselected)
Setting Description
Frequency Error / Frequency
Offset When Auto is enabled, this readout displays frequency error and the measurement
is made at the calculated frequency. When Auto is disabled, this setting changes to
Frequency Offset. When set to Frequency Offset, this setting is used to demodulate a
signal that is not at the center frequency. The measurement is made at the user-entered
offset. The Measurement Filter (if any, speci
fi ed on the Modulation Params tab) is applied
about the offset frequency whether set automatically or manually.
Measurement BW This setting allows you to override the automatic bandwidth calculation and directly enter
a bandwidth value. If you enter a value for the measurement bandwidth, be aware that
the actual bandwidth of data provided to the measurement will be at least as wide as
the value you request and may be as much as two times wider than requested. This
override of the selected measurement bandwidth is done so that the instrument uses
suf
fi cient bandwidth relative to the chosen symbol rate to ensure good signal quality
measurements.
Frequency Deviation For nFSK modulation types, this setting speci fi es the frequency deviation. Select Auto to
make the instrument do this automatically. Deselect Auto to enter a value manually.
This setting is present for only nFSK and C4FM modulation types.
xxx
262
RSA6100A Series Real-Time Spectrum Analyzers Help