Keysight U8903B, User Manual

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Appendixes A
Keysight U8903B User’s Guide 561
Appendix 18: User-defined Filter File Format
Selecting Custom in either the low-pass, high-pass, or weighting filters menu enables you
to load a user-defined filter file.
The available user-defined filter types are IIR (Infinite Impulse Response) and FIR (Finite
Impulse Response). You need to specify the coefficients or sections as well as group delay
for the respective filter type. Use the following examples to configure the filter file format.
The file is saved in the *.juf format.
Example of an FIR filter file format is as follows.
#Type: FIR
#Delay: 250
#Coefficients:
0.00023394
-1.69E-05
-1.61E-05
-1.57E-05
…
The coefficients of the FIR filter are described as follows.
0.00023394 //A[0]
-1.69E-05 //A[1]
-1.61E-05 //A[2]
-1.57E-05 //A[3]
NOTE
The FIR filter transfer function, H(z), is defined as:
H(z) = A[0] + A[1]z
–1
+ A[2]z
–2
+ A[3]z
–3
+ ...
where z = complex variable