SPRUI33H November 2015 – June 2024 TMS320F280040-Q1 , TMS320F280040C-Q1 , TMS320F280041 , TMS320F280041-Q1 , TMS320F280041C , TMS320F280041C-Q1 , TMS320F280045 , TMS320F280048-Q1 , TMS320F280048C-Q1 , TMS320F280049 , TMS320F280049-Q1 , TMS320F280049C , TMS320F280049C-Q1
The data filter is a configurable Sinc filter which supports the following filter types: Sinc1, Sinc2, Sinc3, and SincFast. The data filter OSR (DOSR) settings can be configured from 1 to 256 and is independent of the comparator filter. Effective resolution of the data filter (ENOB) depends upon Data filter type, DOSR, and sigma-delta modulator frequency. By default, the data filter is disabled and setting of SDDFPARMx.FEN = 1 enables the data filter. The data filter output is represented in 26-bit signed integer in two’s complement format. This filter unit translates a low input signal as ‘-1’ and a high input signal as ‘1’. The resulting calculation gives both positive and negative values for the output of the data filter. Table 17-3 shows the different full scale values that the data filter can store using different OSRs.
See Section 17.4.1 to understand how to calculate data rate and latency of data filter.
| DOSR | Sinc1 | Sinc2 | Sinc3 | SincFast |
|---|---|---|---|---|
| x | x | x2 | x3 | 2x2 |
| 4 | –4 to 4 | –16 to 16 | –64 to 64 | –32 to 32 |
| 8 | –8 to 8 | –64 to 64 | –512 to 512 | –128 to 128 |
| 16 | –16 to 16 | –256 to 256 | –4096 to 4096 | –512 to 512 |
| 32 | –32 to 32 | –1024 to 1024 | –32,768 to 32,768 | –2048 to 2048 |
| 64 | –64 to 64 | –4096 to 4096 | –262,144 to 262,144 | –8192 to 8192 |
| 128 | –128 to 128 | –16,384 to 16,384 | –2,097,152 to 2,097,152 | –32,768 to 32,768 |
| 256 | –256 to 256 | –65,536 to 65,536 | –16,777,216 to 16,777,216 | –131,072 to 131,072 |