Timeline for Inter-filter bit width
Current License: CC BY-SA 3.0
11 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jul 18, 2016 at 22:01 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Jun 18, 2016 at 14:44 | answer | added | John McGrath | timeline score: 0 | |
| Jun 17, 2016 at 20:00 | history | edited | robert bristow-johnson | CC BY-SA 3.0 | deleted 98 characters in body |
| Jun 17, 2016 at 19:46 | comment | added | Dan Boschen | In general as a rule of thumb, to maintain a 90 dB signal path SNR, the number of bits in the signal path must be 15 bits ((90-1.76)/6 if a sine wave, more if the peak-avg ratio in your signal is higher), so 16 bits sounds right. The coefficients should be 2 bits larger to ensure the filter rejection will exceed the 90dB (so 18 bits), and then all taps are accumulated with extended precision (at least $log_2(K)$ for a K-tap FIR. The final accumulated result can be scaled back to 16 bits, and you should have no problem with achieving your rejection and SNR requirements. | |
| Jun 17, 2016 at 18:24 | answer | added | Dan Boschen | timeline score: 1 | |
| Jun 17, 2016 at 3:23 | history | edited | Gilles | CC BY-SA 3.0 | improved formatting |
| Jun 17, 2016 at 0:04 | comment | added | Arnfinn | Does the output from the first stage look alright after re-quantizing to 16-bit? It could be a quantization artifact, so depending on how you measure, it could include non-linear effects. Have you tried dithering when re-quantizing? | |
| Jun 16, 2016 at 22:25 | comment | added | Fat32 | ok. I suspect if it's $20 \log_{10}(2^{15}) = 90.30$, very roughly, is the reason why you'll have difficulty in representing a 90 dB dynamic range under 16-Bit uniform quantization. For nonuniform quantization (FPU) things can change. | |
| Jun 16, 2016 at 22:03 | comment | added | John McGrath | This is a fixed-point implementation. I used floating point only to check the delta between the ideal case and the fixed-point case. | |
| Jun 16, 2016 at 21:37 | comment | added | Fat32 | Looking at the question I cannot see if it's a floating point or fixed point or an integer implementation. I think it matters in defining the dynamic range... | |
| Jun 16, 2016 at 21:17 | history | asked | John McGrath | CC BY-SA 3.0 |