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Real-Time I/Q Baseband Generator User’s and Programming Guide
Using Functions
HP ESG Family Signal Generators
Creating User-Defined FIR Filters
Options UN8 and 202
Modifying an Existing FIR Filter with the FIR Table Editor
FIR filters stored in signal generator memory can easily be modified using the FIR table
editor. You can load the FIR table editor with coefficient values from user-defined FIR files
stored in the signal generator’s memory, or from one of the default FIR filters. Then you
can modify the values and store the new file. In this example, you load the FIR table editor
with the values for a default Gaussian filter and then modify it.
Loading the Default Gaussian FIR File
1. Preset the signal generator to normal preset conditions.
2. Press the front panel
Mode
key.
3. In the softkey menu, press
Real Time I/Q BaseBand
(if it appears) >
TDMA
>
EDGE (Rev 8.3.0 Release 1999)
>
More (1 of 2)
>
Modify Standard
>
Filter
>
Define User FIR
>
More (1 of 2)
>
Load Default FIR
>
Gaussian
4. Set the filter BbT to 0.300 (if
Filter BbT
is not already set to this value): Press
Filter BbT
and rotate the front panel knob until 0.300 is displayed.
5. Set the number of filter symbols to 8 (if
Filter Symbols
is not already set to this value):
Press
Filter Symbols
and rotate the front panel knob until 8 is displayed.
6. Press
Generate
. The FIR table editor should now contain the coefficient values for the
specified Gaussian filter.
NOTE
The actual oversample ratio during modulation is automatically selected by
the instrument. A value between 4 and 16 is chosen dependent on the symbol
rate, the number of bits per symbol of the modulation type, and the number of
symbols.
7. Press
Display FFT
for a graphic representation of the filters frequency response as
shown on the following page.
8. To return to the menu keys, press
Return
.
Summary of Contents for ESG series
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