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-1
votes
2answers
31 views

glitches when performing EQ on an OLA FFT

i'm trying to filter a signal with a FFT. I window each block of signal (i use a 4096 points signal) and then remove some high frequencies by just multiplying the magnitude response. the result is : ...
-1
votes
2answers
106 views

C;audio; manipulating with frequencies through fftw

I'm using portaudio for I/O audio streaming, and I wanted to apply some equalization on audio input from microphone. I found that most people refer to fft for task like that, so I use FFTW library in ...
4
votes
4answers
221 views

Why is histogram equalization called as “equalization”?

When output histogram is not same as reference histogram, why is the method called histogram equalization? For example below are two figures from http://en.wikipedia.org/wiki/Histogram_equalization. ...
2
votes
1answer
194 views

Image Contrast Enhancement based Sub-histogram Equalization Technique without Over-equalization Noise

I'm a computer science student and I have an assignment requiring me to implement the algorithm proposed by this paper but I'm hitting a roadblock trying to understand the implementation of one of the ...
2
votes
0answers
223 views

Remove a frequency and all its multiple (harmonics)

In a soundfile, I'd like to remove a frequency and all its harmonics. What is the best solution in your opinion ? 1) Do a loop with 20 notch filters, one after another. ...
0
votes
0answers
61 views

ISI - intersymbol interference

I'm trying to calculate ISI for blind equalizer. Input is $x[n]$ which is complex and $E(x[n])\not =0$. $p[n]$ is defined as convolution noise and $z[n]$ is the equalizer output. $$z[n]=x[n]+p[n]$$ ...
1
vote
2answers
156 views

Berchin's FDLS arbitrary filter design algorithm

i'm trying to use Berchin's FDLS methods (for those that don't know what it is, it's a way to design arbitrary magnitude and phase of an IIR Eq) I tried different things but neither gave me what i ...
0
votes
2answers
187 views

Making an EQ from cascading filters

I hope this isn't a dublicate . I checked but maybe didn't see everything. Here goes : I've been scratching my head over some EQ related questions. I read a lot of papers but my limited math and ...
4
votes
1answer
546 views

What does the one-tap equalizer used with OFDM accomplish?

I've read that OFDM normally uses a one-tap equalizer. It seems that a one-tap equalizer could only scale and delay a signal. Why is this useful? I thought multipath was handled through the ...
3
votes
2answers
221 views

Conditions for precoding matrix to preserve complex conjugate symmetry on DFT vector

Suppose there is a DFT vector $\mathbf{X}$ with length N, which presents complex conjugate symmetry around its middle point, i.e., $X(1) = X(N-1)^*$, $X(2) = X(N - 2)^*$ and so forth. X(0) and X(N/2) ...
1
vote
0answers
85 views

Why histogram equalization fail in ehnanche images for bimodal hisogram?

I'm on histogram equalization process. I have quite well understood the math but i don't understand why an histogram on bimodal image fails in image enhancment and what tecniques can i use in this ...
1
vote
0answers
119 views

Local histogram equalization

I want to learn computer vision and so I downloaded image processing slides from my university archive. I'm on histogram equalization. Learning about local histogram equalization points me out to this ...
5
votes
1answer
479 views

importance of using histogram equalization

I'm reading opencv tutorials and I'm diving into histogram equalization. i have looked in wikipedia, there is a nice example that sums up exactly the problem: original: equalized: but for getting ...
0
votes
1answer
76 views

How best to digitize a noisy phone recording for filtering?

How do I digitize an analog telephone recording and filter it with a Chebyshev filter?
4
votes
1answer
488 views

What methods can be used to remove ringing artifacts in the output of a digital filter?

I'm using digital filters to apply spectral mangling-type special effects to audio. When using a digital filter (vsts/standalone DSP programs/outboard digital filter, etc.), especially when using ...
8
votes
1answer
313 views

General questions on the CMA equalizer

So I recently implemented a CMA equalizer in MATLAB that uses method of steepest descent to converge to the minimal cost. (Im on an equalizer implementation binge). My questions are the following: ...
5
votes
1answer
389 views

How exactly to implement the fractional part of a 'fractional equalizer'?

I have written my own LSE equalizer (that works on the bit level), and literature I have read says that 'fractional' based ones are much better. So how exactly does one get 'fractional' bits? Is it as ...