Rank: 1510 based on 89 downloads (last 30 days) and 2 files submitted
photo

Wessel Lubberhuizen

E-mail
Company/University
Dialog Semiconductor BV

Personal Profile:

 

Watch this Author's files

 

Files Posted by Wessel Lubberhuizen View all
Updated   File Tags Downloads
(last 30 days)
Comments Rating
07 Jun 2010 Screenshot Near Perfect Reconstruction Polyphase Filterbank a near perfect reconstruction polyphase filterbank with two times oversampling Author: Wessel Lubberhuizen filter design, filter analysis, near perfect reconstr... 77 19
  • 4.77778
4.8 | 9 ratings
07 Apr 2008 Screenshot FIRQUEST FIRQUEST optimizes the quantization of FIR coefficients. Author: Wessel Lubberhuizen filter design, filter analysis, fir quantized coeffic... 12 0
Comments and Ratings by Wessel Lubberhuizen View all
Updated File Comments Rating
05 Mar 2011 Near Perfect Reconstruction Polyphase Filterbank a near perfect reconstruction polyphase filterbank with two times oversampling Author: Wessel Lubberhuizen

The Root Raised Error Function (RREF) is defined as sqrt(1-erf(x)), where erf(x) is the well known error function. It is used to shape the frequency response of the subband filters in such a way that neighboring filters are power complementary. It is quite similar to a Root Raised Cosine Function. The RREF is a smooth, rapidly decreasing function. The RREF gives better results than the RRCF when approximated by a finite number filter coefficients.

08 Nov 2009 Near Perfect Reconstruction Polyphase Filterbank a near perfect reconstruction polyphase filterbank with two times oversampling Author: Wessel Lubberhuizen

Hi Wu Liangming, Vlad,

The two statements:
x2(i,:) = x2(i,:) * exp(sqrt(-1)*pi*(i-1)/N);
x2(i,2:2:M) = -x2(i,2:2:M);

Are equivalent to:

x2(i,j) = x2(i,j) * exp(sqrt(-1)*pi*((i-1)+j*N)/N)

Indeed, this corresponds to a frequency shift by 0.5 times the subband width.

Vlad, you are right, this can also be done by the fft. In that case, you would first combine x1 and x2 to a single matrix, which is passed though the fft. I'll try to update the code so it incorperates this idea, and also check whether it works with dct instead of fft.

For an approach to reduce the delay of a filter bank, see:
http://iwaenc05.ele.tue.nl/proceedings/papers/S04-05.pdf

30 Aug 2009 Near Perfect Reconstruction Polyphase Filterbank a near perfect reconstruction polyphase filterbank with two times oversampling Author: Wessel Lubberhuizen

Hua, you can make a complex signal real by upsampling and frequency shifting. But why would you want to do that?

15 Feb 2009 Near Perfect Reconstruction Polyphase Filterbank a near perfect reconstruction polyphase filterbank with two times oversampling Author: Wessel Lubberhuizen

That is correct. A high spectral resolution inherently requires a large temporal delay.

Comments and Ratings on Wessel Lubberhuizen's Files View all
Updated File Comment by Comments Rating
23 Sep 2014 Near Perfect Reconstruction Polyphase Filterbank a near perfect reconstruction polyphase filterbank with two times oversampling Author: Wessel Lubberhuizen Xianhai

Very nice jobs!

01 Mar 2014 Near Perfect Reconstruction Polyphase Filterbank a near perfect reconstruction polyphase filterbank with two times oversampling Author: Wessel Lubberhuizen Homa Esfahanizadeh

18 Apr 2013 Near Perfect Reconstruction Polyphase Filterbank a near perfect reconstruction polyphase filterbank with two times oversampling Author: Wessel Lubberhuizen Yang

Hi Wessel,

Thank you for your perfect job!

I have a question here. You mentioned that this is an oversampling implementation (two-times. For the output of npr_analysis, is it already decimated? Similarly, for the output of npr_synthesis, is it already interpolated?

Thank you very much!

30 Nov 2012 Near Perfect Reconstruction Polyphase Filterbank a near perfect reconstruction polyphase filterbank with two times oversampling Author: Wessel Lubberhuizen Ken

Hello,Wessel Lubberhuizen!
I am a student of Chinese Academy of Sciences.It is really great share your work.I have run your Matlab code on Near Perfect Reconstruction Polyphase Filterbank, but I don't quit understand the principle on this algorithm.Would you please share the paper about the algorithm.
Your response will be appreciated!

04 Jun 2012 Near Perfect Reconstruction Polyphase Filterbank a near perfect reconstruction polyphase filterbank with two times oversampling Author: Wessel Lubberhuizen Kanishk

Hello Mr Wessel,
I studied your code and I must commend you for your wonderful work.
However, I am not able to understand how it works. All the scripts and references I have read, speak about two analysis IDFT filter banks where the input signal is fed with and without delay of M/2 (M = number of polyphase components).
In your code, you introduced a frequency shift for the lower filter bank signal and inverted the sign for every alternate column. Could you perhaps provide your reference. I would very much appreciate it.

Also, the rref function was genius :)

Contact us