Hi, I am trying to implement leaky NLMS for adaptive beamforming, but I found that the noise reduction performance is worse than that of NLMS. The data I used are simulated data, and I assume the noise and speech sources are well seperated. Can anybody give me some suggestions about applying leaky NLMS for GSC? Is Leaky really better than that of NLMS? Thanks a lot! Best Regards, Jing
Can anybody tell me sth. about Leaky NLMS
Started by ●January 10, 2006
Reply by ●January 10, 20062006-01-10
"Jing" <jing.deng@gmail.com> wrote in message news:9sWdnSfENbOQg1nenZ2dnUVZ_s-dnZ2d@giganews.com...> Hi, > > I am trying to implement leaky NLMS for adaptive beamforming, but I found > that the noise reduction performance is worse than that of NLMS. The data > I used are simulated data, and I assume the noise and speech sources are > well seperated. Can anybody give me some suggestions about applying leaky > NLMS for GSC? Is Leaky really better than that of NLMS? > > Thanks a lot! > > Best Regards, > Jing > > >I suspect that leaky anything won't be as good as pure integrators in an algorithm. For stationary data NLMS woudl come out on top. Try non-stationary data - the leaky one may track better. Naebad
Reply by ●January 10, 20062006-01-10
Jing wrote:> Hi, > > I am trying to implement leaky NLMS for adaptive beamforming, but I found > that the noise reduction performance is worse than that of NLMS.Yes, this is what expected.> The data > I used are simulated data, and I assume the noise and speech sources are > well seperated. Can anybody give me some suggestions about applying leaky > NLMS for GSC? Is Leaky really better than that of NLMS? >It depends. The amount of leak is the tradeoff between the stability and the accuracy. You should optimize it for your application. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Reply by ●January 11, 20062006-01-11
Jing wrote:> Hi, > > I am trying to implement leaky NLMS for adaptive beamforming, but I found > that the noise reduction performance is worse than that of NLMS. The data > I used are simulated data, and I assume the noise and speech sources are > well seperated. Can anybody give me some suggestions about applying leaky > NLMS for GSC? Is Leaky really better than that of NLMS?Leaking will always make the adaption accuracy poorer than not leaking. Think about it - you keep shrinking the coefficients, so the adaption is always fighting to reach its target. It never quite gets there. Leaking is a way to stop coefficients wandering off to extreme values. This can happen at places where the signal is always close to zero (think of things like the mid-point between symbols in a channel equalizer). No matter how far off the coefficient wanders big_coeff*tiny_signal is always very small, and never coaxed the wandering coefficient back towards zero. If you face wandering coefficients, leaking is a huge benefit. If you don't, leaking is a looser. The level of leaking you should use is a compromise between stopping the coefficient wandering (big leak is better) and avoiding detuning of the adaption (small leak is better). Regards, Steve