3 IQ Analyzer (Basic) Mode
3.1 Complex Spectrum Measurement
[n]?
the measurement, then retrieves the data specified by n
:READ:SPECtrum[n]?
Starts the measurement, then retrieves the data specified by n
Remote Command Results
The following table lists results returned by the :FETCh, :MEASure, and :READ
queries, depending on the specified value of n. Note that the marker values are x, y
pairs.
n Return Value
0 Returns unprocessed I/Q trace data, as a series of trace point values, in volts. The I values are listed first in
each pair, using the 0 through even-indexed values. The Q values are the odd-indexed values
Not specified
or 1
Returns the following comma-separated scalar results:
1 FFT peak is the FFT peak amplitude
2 FFT frequency is the FFT frequency of the peak amplitude
3 FFT points is the Number of points in the FFT spectrum
4 First FFT frequency is the frequency of the first FFT point of the spectrum
5 FFT spacing is the frequency spacing between the FFT points of the spectrum
6 Time domain points is the number of points in the time domain trace used for the FFT. The
number of points doubles if the data is complex instead of real. See the time domain scalar
description below
7 First time point is the time of the first time domain point, where time zero is the trigger
event
8 Time spacing is the time spacing between the time domain points. The time spacing value
doubles if the data is complex instead of real. See the time domain scaler description
below
9 Time domain returns a 1 if time domain is complex (I/Q) and complex data will be returned.
It returns a 0 if the data is real. (raw ADC samples) When this value is 1 rather than 0
(complex vs. real data), the time domain points and the time spacing scalers both increase
by a factor of two
10 Scan time is the total scan time of the time domain trace used for the FFT. The total scan
time = (time spacing) x (time domain points − 1)
11 Current average count is the current number of data measurements that have already been
combined, in the averaging calculation
2 Returns the trace data of the log-magnitude versus time (that is, the RF envelope)
3 If "Invert Spectrum" on page 267 is INVert, returns conjugated I and Q trace data, otherwise (Invert
Spectrum is NORMal) returns I and Q trace data, represented by I and Q pairs (in Volts) versus time
4 Returns spectrum trace data. That is, the trace of log-magnitude versus frequency (the trace is computed
using an FFT)
5 Returns the averaged trace data of log-magnitude versus time (that is, the RF envelope)
6 Not used
7 Returns the averaged spectrum trace data (that is, the trace of the averaged log-magnitude versus
IQ Analyzer Mode User's &Programmer's Reference 144
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