SPRUIZ1B July 2023 – August 2024 TMS320F28P650DH , TMS320F28P650DK , TMS320F28P650SH , TMS320F28P650SK , TMS320F28P659DH-Q1 , TMS320F28P659DK-Q1 , TMS320F28P659SH-Q1
The following equations can be used to derive a theoretical filter output of an SDFM filter output for both a comparator filter and a data filter.
Where:
For example, when using the AMC1306x25 modulator:
AMC1306x25 | Vclipping = | 320mV |
Input voltage (AINP - AINN) = | 100mV | |
SDFM filter settings | Filter type = | 3 |
Comparator OSR (COSR) = | 32 | |
Data filter OSR (DOSR) = | 100 |
Density of 1s in bit stream | Using Equation 30 | 0.65625 |
Comparator filter output | Using Equation 31 | 21504 |
Filter type = Sinc3 | ||
COSR = 32 | ||
Data filter output (32-bit) | Using Equation 32 and Equation 33 | 312500 |
Filter type = Sinc3 | ||
DOSR = 100 | ||
Data filter output (32-bit) | Using Equation 34 | 9765 |
Filter type = Sinc3 | ||
DOSR = 100 | ||
(Right shift by 5) |