Keysight EXG and MXG X-Series Signal Generators User’s Guide 131Optimizing Performance for All ModelsUsing Filters (N5162A and N5182A Only)Finite Impulse Response filters can be created and used with both dual arbitrary waveformgenerated waveforms and real-time baseband generated waveforms. For this example, the filter isdefined within the CDMA2000 digital communications format, a dual arbitrary waveform generatedstate.Dual ARB Modulation Filter TypesArb Custom Modulation Filter Types on page 133Dual ARB Modulation Filter TypesIn 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 inthe 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” onpage 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 modulationfilter effectively compresses a single carrier I/Q waveform down to just the I/Q constellation pointsand then controls the transitions similar to the modulation filter in Arb Custom modulation. The keydifference 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 canbe internally generated, using a default equalization FIR filter that can either be selected on its ownor convolved with the selected User FIR Filter. The default equalization FIR Filter is an 80% ofNyquist filter. Refer to “Using the Equalization Filter” on page 217.The Dual ARB Modulation mode uses complex and real filters. Refer to Creating Complex Filterswith Dual ARB Modulation and to “Creating Complex Filters with Dual ARB Modulation” onpage 131.Creating Complex Filters with Dual ARB ModulationThe complex filter applies user-defined coefficients (I + jQ) to a waveform that defines thetransitions between the symbol transition points. The complex filter is only available for Dual ARBwaveforms.NOTE If a complex correction filter calibration is required, the user can provide thecomplex filter values consisting of the complex real (R) and the imaginary (I)coefficients to implement the output filter corrections. Correction coefficientscan be generated by tools such as Matlab and then uploaded into the MXG.Filter coefficients cannot be generated internally in the MXG. Refer to Matlabsample in the Programming Guide. For more on equalization filters, refer to“Using the Equalization Filter” on page 217.
