Agilent Technologies E4406A VSA Series Programmer's Manual page 184

Language Reference
CALCulate Subsystem
Example: Select the spectrum measurement.
Use CALC:DATA4:PEAK? -40,10,FREQ to identify the
peaks above -40 dBm, with excursions of at least 10 dB,
in order of increasing frequency.
Query Results: Returns a list of floating-point numbers. The first value
in the list is the number of peak points that follow. A
peak point consists of two values: a peak amplitude
followed by the its corresponding frequency (or time).
If no peaks are found the peak list will consist of only
the number of peaks, (0).
The peak list is limited to 100 peaks. Peaks in excess of
100 are ignored.
Remarks: This command uses the data setting specified by the
FORMat:DATA command and can return real 32-bit,
real 64-bit, or ASCII data. The default data format is
ASCII.
History: Added in revision A.03.00 and later
184 Chapter 5