To Create A User-Defined Filter - Agilent Technologies 89410A Operator's Manual

Creating User-defined Signals (Options AYA and AYH)

To create a user-defined filter

This task shows you how to create filters that you can use as the
measured or reference filter. This task uses digital demodulation. If you
want to perform this task using video demodulation, choose video
demodulation instead of digital demodulation in step 4.
1.
Create a file defining your desired filter:
You may use common software packages such at MATLAB or Mathcad to
define the filter shape. For digital demodulation, you must use 20 points
per symbol and you may use a maximum of 20 symbols. For video
demodulation, you must use 40 points per symbol and you may use a
maximum of 20 symbols. A good choice for a total number of defined
points is 401 for digital demodulation and 801 for video demodulation (this
allows you to define a center point symbol in order to achieve symmetry)
2.
Convert the file to SDF using the Standard Format Data Utilities supplied with
the analyzer:
As an example, use a PC to convert an ASCII file to SDF:
asctosdf <source file> <destination file>
The destination disk must be compatible with your analyzer's disk drive
(DS,HD).
3.
View the filter's impulse response:
Press [ ], [
Save/Recall
Press [
Measurement Data
trace.
4.
Apply the filter to your signal:
Press [
Instrument Mode
[ ], [
Instrument Mode demod type
Press
[demodulation setup
Pre ss [ ] or [
meas filter
Select a user data register Dx.
The Signals Disk contains an example of a user defined filter. The trace
version of the filter is stored as "GAUSS1.DAT" and the ASCII version is
stored as "GAUSS1.ASC" It is a Gaussian filter 6 symbols (121 pts) wide,
with 20 points per symbol, and a BT of 1.0. You might use this type of
filter on an MSK signal.
The documentation for the Standard Data Format Utilities which
accompanies this analyzer also includes a section (Mathcad Examples)
describing how to create waveforms and filters for use with this analyzer.
11 - 6
], [ ].
recall trace from file into Dx
], [ ]; select the data register that has your
data reg
], [ ] (with option AYH, press
Digital Demodulation
], [ ], [
Digital Demodulation
].
], [ ].
ref filter user defined
).
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