TE5251
User Manual
4-58
Hopping
Modulation
Programming
parameters. Hop control is internal. The frequency will hop from
frequency to frequency at a rate determined by the dwell time value
and controlled by a sequence of frequencies in the HOP data table.
There are two hop modes: Fixed Dwell, where the rate of which the
generator hops from frequency to frequency is constant and
Variable Dwell, where the rate of which the generator hops from
frequency to frequency is programmable for each hop.
The commands for programming the frequency hopping function
are described below. Note that the carrier waveform frequency
(CW) setting is common to all modulation schemes.
FHOP:DWELl:MODe(FIXed|VARiable}(?)
Description
This selects between fixed or variable dwell-time for the frequency hops. Select the fixed option if you want
each frequency to dwell equally on each step. The variable option lets you program different dwell times for
each frequency hop. The 5251 output hops from one frequency to the next according to a sequence given
in a hop table. The variable dwell time table contains dwell time data for each step however, the fixed dwell
time table does not contain any dwell time information and therefore, if you select the fixed option, make
sure your dwell time is programmed as required.
Parameters
Name
Type
Default
Description
FIXed
Discrete
FIX
Selects the fixed dwell time frequency hops mode
VARiable
Discrete
Select the variable dwell time frequency hops mode
Response
The 5251 will return FIX, or VAR depending on the selected dwell setting.
FHOP:DWELl<dwell_time>(?)
Description
This selects the dwell time for frequency hops when the selected mode is Fixed dwell time hops. The dwell
time table in this case does not contain the dwell time per step parameters and therefore, the value which is
programmed with this command remains constant for the entire hop sequence.
Parameters
Name
Range
Type
Default
Description
<dwell_time>
200e-9
to 20
Numeric
200e-9
Programs dwell time for the fixed dwell-time
frequency hop function. The same dwell time will be
valid for each frequency hop. Dwell time is
programmed in units of s.
Response
The 5251 will return the present dwell time value. The returned value will be in standard scientific format (for
example: 100mHz would be returned as 100e-3 – positive numbers are unsigned).
FHOP:FIX:DATA<fix_hop_data>
Summary of Contents for 5251
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