implement AEC on DSP

Started by June 13, 2007
I have implement an AEC algorithm (Frequency Domain NLMS) on DSP (TI c5509), but when I test it in real room the ERLE is 16dB(with white noise), will test by compositive speech source with line_in the ERLE is 25dB.
But, I always see that some AEC product's ERLE can get 25dB-30dB, So I want to konw the method they test.
1,what's the test source. white noise or speech signal?
2,what's the test environment of there test?
3,commonly, with a 16bit fixed-point DSP,what's the highest performance can it get?
thanks a million!!!