Keysight EXG and MXG X-Series Signal Generators User’s Guide 131
Optimizing Performance for All Models
Using Filters (N5162A and N5182A Only)
Finite Impulse Response filters can be created and used with both dual arbitrary waveform
generated waveforms and real-time baseband generated waveforms. For this example, the filter is
defined within the CDMA2000 digital communications format, a dual arbitrary waveform generated
state.
Dual ARB Modulation Filter Types
Arb Custom Modulation Filter Types on page 133
Dual ARB Modulation Filter Types
In addition to the default filter formats (examples: Root Nyquist, Nyquist, Gaussian, etcetera),
customized user FIRs can be created using the User FIR tables to create the filter coefficients in
the MXG or the filter coefficients can be created and downloaded using programs like MatLab.
For information on using default filters and FIR filters in Dual ARB Modulation mode refer to:
“Using Finite Impulse Response (FIR) Filters in the Dual ARB Real-Time Modulation Filter” on
page 219.
“Modifying a FIR Filter Using the FIR Table Editor” on page 225.
The Dual ARB Modulation mode also has arb real-time modulation filters. The real-time modulation
filter effectively compresses a single carrier I/Q waveform down to just the I/Q constellation points
and then controls the transitions similar to the modulation filter in Arb Custom modulation. The key
difference is that this filter is applied as the waveform plays, rather than in the waveform data itself.
The real-time modulation filter is only available for Dual ARB waveforms.
Refer to “Setting the Real-Time Modulation Filter” on page 232.
The Dual ARB Modulation mode also has equalization filters. An internal I/Q path optimization can
be internally generated, using a default equalization FIR filter that can either be selected on its own
or convolved with the selected User FIR Filter. The default equalization FIR Filter is an 80% of
Nyquist filter. Refer to “Using the Equalization Filter” on page 217.
The Dual ARB Modulation mode uses complex and real filters. Refer to Creating Complex Filters
with Dual ARB Modulation and to “Creating Complex Filters with Dual ARB Modulation” on
page 131.
Creating Complex Filters with Dual ARB Modulation
The complex filter applies user-defined coefficients (I + jQ) to a waveform that defines the
transitions between the symbol transition points. The complex filter is only available for Dual ARB
waveforms.
NOTE If a complex correction filter calibration is required, the user can provide the
complex filter values consisting of the complex real (R) and the imaginary (I)
coefficients to implement the output filter corrections. Correction coefficients
can be generated by tools such as Matlab and then uploaded into the MXG.
Filter coefficients cannot be generated internally in the MXG. Refer to Matlab
sample in the Programming Guide. For more on equalization filters, refer to
“Using the Equalization Filter” on page 217.
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