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SPPDF-01 Development Suite
User’s Manual
Introduction
Chapter I
3
The SPPDF-01 is a FIR Filter Design Suite for the SPPDM-01 dual channel, FIR filter plat-
form with analog I/O that utilizes Frequency Devices MatLab
TM
GUI with MatLab
TM
V5.3 or
MatLab
TM
V6.0.
The SPPDF-01 Suite consists of:
•
An SPPDM-01 dual channel signal processing platform containing a MatLab
TM
compatible
FIR filter algorithm
•
An SPPDB-01 development board for the SPPDM-01,
•
An RS232, DB9 cable, and
•
A CDRom with CDDF-01 software containing this manual, data sheets for the SPPDF-01,
SPPDM-01 and SPPDB-01, and the following utilities:
1. Filter Coefficient Generator (FCG) Software – This FCG software provides coeffi-
cient data conversion for FIR filters in the frequency domain and generates sets of
coefficients for single or multiple filters between 100 Hz and 20.0 kHz. From a set of
specifications, FCG produces a data set that approximates the given filter characteris-
tics in the frequency domain. The FCG software is a tool compatible with MatLab
TM
V5.3 or MatLab
TM
V6.0 and allows the user to evaluate and modify low-pass, high-
pass, band-pass, and band-reject filters.
2. Filter Coefficient Loader (FCL) Software – FCL software is the communication and
translation interface that loads single or multiple sets of coefficients for various FIR fil-
ter types into the SPPDM-01 platform’s flash memory implementing the direct applica-
tion, physical realization, and usage of the FIR filters. Coefficient loading utilizes the
RS232 interface on the SPPDB-01 development board to communicate with MatLab
TM
V5.3 or MatLab
TM
V6.0 FIR filter coefficient library files
Appendix C of this manual has information on how to add field programming capabili-
ty. A circuit diagram is provided that may be added to the field application of the SPPDM-01
which emulates the SPPDB-01 development board and permits field loading of new filter
coefficient sets.
1.1 Hardware Description
The SPPDM-01 has a double precision FIR filter algorithm programmed into its EEPROM that
provides two channels of FIR filtering. Each channel is independently programmed and the FIR
algorithm can be configured, shaped or altered in terms of; corner frequency, number of taps
(shape factor) and filter type simply by loading different sets of coefficients. The FIR filter data
comes from a dual 24-bit sigma-delta ADC on the SPPDM-01. This 24-bit data is left-shifted to
automatically become a 32-bit double word. The on-board DSP reads a 32-bit coefficient set
from Flash Memory for each channel according to the user’s selection. Finally, the digital output
of the DSP is filtered and fed sequentially into a dual 24-bit DAC for conversion of the now fil-
tered analog signals. The 2 Megabits Flash Memory permits many coefficient sets to be stored
and user addressed for maximum flexibility.
Many FIR filter types can be implemented with the DSP algorithm, provided the MatLab
TM
utili-
ty converges mathematically and the user stays within the 100 Hz to 20.0 kHz frequency range.
The number of filter channel taps for each filter channel must be
≤
300.
