Matlab is an excellent tool to use when analyzing sampled signals in ways that the various Real-Time Spectrum Analyzer models do not currently support. This document is intended to be used by users who are familiar with Matlab, but need to “bridge the gap” between the data format produced by the RTSA and their analysis software.
This document is a work in progress. Currently, the topics covered are:
n Importing IQ data which is saved as a . MAT file from the RSA6100 or RSA3000
n Using the correct calculation for power in both time and frequency domains
Importing I/Q samples into Matlab
The RTSA can save samples in multiple formats, including .MAT. This .MAT file format includes the I and Q samples and enough information for Matlab to import the data and various other ancillary parameters easily. The file format is intended to be suitable for importing into the Agilent 89600 software.
To import the .MAT file (in this case “reference.mat”), use the “load” command:
>> load reference.mat
You can also find out what variables are in the .mat files (which ones will be assigned when the load command is used) with “whos -file”:
>> whos -file reference.mat
Name Size Bytes Class Attributes
InputCenter 1x1 8 double
InputZoom 1x1 1 uint8
XDelta 1x1 8 double
Y 6966x1 55728 single complex
For now, we’ll be mostly concerned with Y, the actual I/Q samples. As “whos” shows, this is a single-dimensioned array of complex values. The Real part of each value is I and the Imaginary part is Q. The other values in the file are:
n InputCenter: The center frequency of the acquisition band.
n InputZoom: A flag. Indicating that the I/Q samples have been converted to baseband (“Zoomed”).
n XDelta: The sample period. SamplingRate = 1/XDelta.
This document is a work in progress. Currently, the topics covered are:
n Importing IQ data which is saved as a . MAT file from the RSA6100 or RSA3000
n Using the correct calculation for power in both time and frequency domains
Importing I/Q samples into Matlab
The RTSA can save samples in multiple formats, including .MAT. This .MAT file format includes the I and Q samples and enough information for Matlab to import the data and various other ancillary parameters easily. The file format is intended to be suitable for importing into the Agilent 89600 software.
To import the .MAT file (in this case “reference.mat”), use the “load” command:
>> load reference.mat
You can also find out what variables are in the .mat files (which ones will be assigned when the load command is used) with “whos -file”:
>> whos -file reference.mat
Name Size Bytes Class Attributes
InputCenter 1x1 8 double
InputZoom 1x1 1 uint8
XDelta 1x1 8 double
Y 6966x1 55728 single complex
For now, we’ll be mostly concerned with Y, the actual I/Q samples. As “whos” shows, this is a single-dimensioned array of complex values. The Real part of each value is I and the Imaginary part is Q. The other values in the file are:
n InputCenter: The center frequency of the acquisition band.
n InputZoom: A flag. Indicating that the I/Q samples have been converted to baseband (“Zoomed”).
n XDelta: The sample period. SamplingRate = 1/XDelta.
