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SPPDF-01 Development Suite
User’s Manual
Introduction
Chapter I
1.2 Software Description
Users can define and configure filters using FREQUENCY DEVICES’ SPPDF-01 Filter
Coefficient Generator (FCG) software. The FCG - GUI is invoked from within the MatLab
TM
(User Supplied) environment and sends commands to the MatLab
TM
engine using the specific fil-
ter values loaded into the FCG – GUI. The MatLab
TM
engine responds to FCG commands and
calculates coefficient sets for the indicated FIR filters. These coefficient sets are temporarily
stored in the MatLab
TM
workspace environment. The filter response is displayed graphically with-
in MatLab
TM
for verification of program convergence and acceptability. To prevent loss, the coeffi-
cients sets can be stored as files on the PC in a designated folder, before exiting MatLab
TM
.
Note: the FCG software is provided as a convenience to the user. It is a tool to
facilitate standard FIR filter design. Experienced MatLab
TM
users may design their own
custom FIR filters for the SPPDM-01 using the appropriate MatLab
TM
FIR design tools, as
long as SPPDF-01 design constraints are met.
Design constraints on the SPPDM-01 FIR Filter Platform are:
•
Frequency Range: 100 Hz to 20 kHz
•
Maximum Number of Taps: 300.
Note: Low-pass and high-pass filters are easily configured but some versions of band-
pass and band-reject filters might not converge mathematically within some of the con-
straints. User may be required to try other parameter combinations until a converging
implementation is found.
Chapter II of this document will be directed to MatLab
TM
users who wish to use Frequency
Devices’ FCG-GUI to design standard FIR filters for the SPPDM-01. The experienced MatLab
TM
filter designer may skip Chapter II and go right to Chapter III, the Filter Coefficient Loader (FCL)
section.
The FCG software is a design tool for FIR filters to be used within the MatLab
TM
environ-
ment. The FCG software provides for the entry of specific filter parameters into the MatLab
TM
environment allowing the MatLab
TM
engine to calculate coefficients that approximate the given fil-
ter descriptions.
User must first determine filter type, followed by selection of various specification parame-
ters. Based on the selected values, MatLab
TM
creates a best approximation set of coefficients.
This set of coefficients corresponds to a single or multiple number of filters and may be managed
in two modes: Immediate and Batch.
•
Immediate Mode of operation relies on the MatLab
TM
workspace to present the set of
coefficients as an M x N matrix where M is the number of filters and N is the number
of coefficients for each filter. See Appendix A - Examples 2 and 3.
•
Batch Mode of operation creates a text batch file where the system saves the set
of coefficients uniquely identified by the various filters. See Appendix A – Examples
4 and 5.
5
