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SPPDF-01 Development Suite
User’s Manual
Filter Coefficient Generator
Chapter II
The main panel GUI is divided into five functional groups. Note: All entries or selections must
be completed in all groups before the "Apply" command (which initiates the filter coeffi-
cient generation) is executed.
2.2.1 Group A, Filter (Items 1 - 5) - contain the controls necessary to specify the parameters
used in the generation of sets of coefficients for single or multiple filters over a predefined
bandwidth.
1. Filter Type List Control: Is used to select filter type. Select Low-Pass, High-Pass,
Band-Pass or Band-Stop. The default value shown at startup is Low-Pass. When
selecting Low-Pass or High-Pass Filter Type, the Second Pass-band Cutoff Input
Control (Fp2) and the Second Stop-band Cutoff Input Control (Fs2) will be disabled.
2. Sampling Frequency Input Control: Specifies the sampling frequency. Sampling fre-
quency must be entered. Required sampling rate for the SPPDM-01 family of prod-
ucts is always 48000Hz.
3. Frequency Step Input Control: Enters a constant that represents the frequency steps
for the generation of the sets of filter coefficients over the bandwidth for a particular fil-
ter. Since there is a limit to the maximum number of steps, small step sizes may limit
bandwidth. The Frequency Step (Fstep) represents a positive number limited by
SPPDM-01 family parameters such as the Maximum Bandwidth (MB) (100 to 20,000
Hz) and the Maximum Number of Filters (MNF = 512). For a specific filter, the Per Step
Maximum Number of Filters (PSMNF) is calculated to be PSMNF = MB / Fstep. This
value must be greater than one and less than MNF. The frequency step value is mean-
ingless when only one set of filter coefficients is generated. A valid Fstep must be
entered.
4. From: Range Input Control is used to enter a numeric value for the lowest bandwidth
limit. It represents the starting point in the generation of the sets of filter coefficients.
The “To” (Item 5) is enabled when a valid number is entered into From. The number
must be between 1 and the MNF of 512.
5. To: Range Input Control enters a numeric value for the highest bandwidth limit. It rep-
resents the end point used in the generation of the sets of filter coefficients. The num-
ber must be between 1 and 512 for the frequency step. The number must be equal or
greater than the “From” number (Item 4). This control remains disabled until a valid
From value is entered. Then a valid To value can be entered.
2.2.2 Group B, Signal (Items 6 - 11) - are the controls used to input the relative specifications
for the filter(s) described in Group A.
6. Fp/Fp1: First Pass-band Cutoff Input Control enters a numeric value interpreted as
Pass-band Cutoff Frequency (Fp in Hz) for low-pass and high-pass type filters and as
First Pass-band Cutoff (Fp1) frequency for band-pass and band-stop type filters.
7. Fp2: Second Pass-band Cutoff Input Control enters a numeric value interpreted as
Second Pass-band Cutoff Frequency (Fp2 in Hz) for band-pass and band-stop type fil-
ters. This control is enabled only when the Filter Type (Item 1, Figure 1) selected is
either Band-Pass or Band-Stop.
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