Mark Borgerding 7ec9402d5b Fixed point works (in the loosest sense of the word "works") ...

Fixed point sums are divided by 2 each stage.  This will never overflow for radix 2 ffts.
For mixed radix, it may overflow, but will usually give better SNR.

'make test' output:

### testing SNR for  1024 point FFTs
#### DOUBLE
snr_t2f = 295.30
snr_f2t = 308.25
#### FLOAT
snr_t2f = 146.92
snr_f2t = 143.25
#### SHORT
snr_t2f = 54.645
snr_f2t = 24.677

#### timing 10000 x 1024 point FFTs
#### DOUBLE
Elapsed:0:25.96 user:19.77 sys:0.22
#### FLOAT
Elapsed:0:06.62 user:5.48 sys:0.11
#### SHORT
Elapsed:0:06.01 user:4.75 sys:0.12

2003-10-11 14:34:01 +00:00

6.3 KiB

Raw Blame History

View Raw