Instrument Configuration 3Keysight U8903A User’s Guide 79Digital filtersDigital filters are used to bandwidth limit the input signals before applying ameasurement function. There are three selectable filter types consisting of lowpass, high pass, and weighting as shown in the figure below. Up to three filters,one from each type, can be applied to the signal simultaneously. The U8903A alsoallows user-defined filters to be uploaded to the device. Refer to “Appendix C:User-defined Filter File Format” on page 162 for more information on theuser-defined filter file format.Figure 3-5 Digital filter selectionThe low pass, high pass, and weighting filter selection is as follows.Table 3-1 Filter selectionLow pass filter High pass filter Weighting fil ter15 kHz 22 Hz A-Weighting20 kHz 100 Hz CCIR-1k weighted30 kHz 400 Hz CCIR-2k weightedUser-defined User-defined C-MessageCCITTUser-defined
