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9 votes
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How do software equalizers work?

This depends a lot on how you implement it. A single biquad takes about 10 arithmetic operations. (To be precise a Transposed Form II takes 4-5 multiplies and 3 adds, depending on how the gain ...
Hilmar's user avatar
  • 46.2k
5 votes

How do software equalizers work?

I don’t think you’re alone, but essentially this is simply a problem of optimization. Let’s say you have a processor with a 88MHz clock. That’s 2k clocks per sample at 44kHz. If we take the term ‘...
Dan Szabo's user avatar
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5 votes

Least Squares Solution Using the DFT vs Wiener-Hopf Equations

Following Royi's derivation, we want to show that, $$\begin{align} \hat{h} = \arg \min_h||Xh - y||^2 = (X^T X)^{-1} X^H y = IDFT(Y \oslash X) \end{align}$$ where $X$ is a circular convolution matrix ...
orchi_d's user avatar
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3 votes
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Distortion of OFDM signal when using RRC filter

I checked your code in my PC, you need just to delete the delay added before the filter. For example, you can use: U_aft_fil = U_aft_fil(fil_delay+1:end); Then ...
Zeyad_Zeyad's user avatar
  • 1,056
3 votes
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Does zero-forcing equalizer need known channel impulse response?

If the received signal can be written as $$\mathbf{y} = \mathbf{H}\,\mathbf{x} + \mathbf{n}$$ where $\mathbf{H}$ is the channel matrix, $\mathbf{x}$ is the transmitted vector, and $\mathbf{n}$ is ...
BlackMath's user avatar
  • 675
3 votes

Deciding an EQ's Center Frequencies

The audible range is about 10 octaves, and usually the center frequencies of a graphic equalizer would be distributed equally spaced on a log scale to cover that range. Common equalizers have either $...
Matt L.'s user avatar
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3 votes

Equalize Speaker using impulse response

This depends a bit on what you want to get out of this and how much effort/work you are willing to put in. Doing a room EQ that actually works and makes it sound consistently better is quite ...
Hilmar's user avatar
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3 votes
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Calculate Q factor of a Low Shelf and High Shelf filter

it looks like this eq10q uses cascaded parametric EQs, initially set up to be bell, but switchable to other types (like shelving). i wouldn't doubt that they're using the audio EQ cookbook. if you'...
robert bristow-johnson's user avatar
3 votes

Does an audio equalizer consist of a perfect-reconstruction filterbank?

A filter bank system is generally composed of: an analysis filter bank, that split an input signal into components with filters and may reduce their rate a synthesis filter bank (FB), that takes the ...
Laurent Duval's user avatar
3 votes
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where we use estimation and detection in communication system?

Don't worry too much about defining these terms too precisely, because they are used in many contexts with slightly different meanings. In very general terms, "estimation" is the calculation ...
MBaz's user avatar
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3 votes
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Square Root MMSE

This is just a nice way to rewrite Equation (2). Using Block matrix interpretation: \begin{align} \underline{H}^H\underline{H}=\begin{bmatrix}H_{R\times T}^H&\sigma I_T\end{bmatrix}\begin{bmatrix}...
AlexTP's user avatar
  • 6,605
3 votes
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Requirements on Signal Spectrum for Fractionally Spaced Equalization

As far as equalizer performance and possible limitations I provide two key points below about the span of the equalizer and the number of samples per symbol to use. The equalizer duration in time is ...
Dan Boschen's user avatar
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3 votes

request pointers on beginner DSP board for making an EQ simulating hearing aid prescription with TV sound

So, first off: ebay is never a good source for electronics. There's various large electronics distributors (digikey, mouser, farnell/element14…) in India, so that's really not a problem. But: For ...
Marcus Müller's user avatar
2 votes

Does an audio equalizer consist of a perfect-reconstruction filterbank?

Does an audio equalizer consist of a perfect-reconstruction filterbank? Short answer: No. It's a bit unsharp what you're asking here, since reconstruction filterbanks are usually things that combine ...
Marcus Müller's user avatar
2 votes
Accepted

Is the Channel shortening similar to Time domain Equalizer (TEQ)

Most likely people use different words to describe the same concept. This happens quite often. The TEQ is the more general term and also used to equalize other methods that OFDM, while CS is related ...
Zeyad_Zeyad's user avatar
  • 1,056
2 votes

Inter Symbol Interference (ISI) / Equalization in Digital Signal Processing

If the channel just adds noise and does not cause any distortion (as in the first figure), you can design the transmit filter $g(t)$ such that, when combined with its matched filter at the receiver, ...
Matt L.'s user avatar
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2 votes
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Approximate IIR filter with FIR filter with energy restrictions

This could be homework, so I'll only give you a few hints to help you solve the problem yourself. Remember that a ZF equalizer just inverts the channel, so if $D(z)$ is the equalizer's transfer ...
Matt L.'s user avatar
  • 90.6k
2 votes

Study materials for Decision feedback equalizer

Not a comprehensive source of details, but for me this paper/tutorial has been the most helpful in terms of principles explanation. Also here you can find a basic working example of DFE implementation ...
megasplash's user avatar
2 votes

Peaking filter (loudness) cutoff frequency in an equalizer

The purpose of the loudness filter is to compensate for the level dependency of the a human's "frequency response". Most music is mixed at pretty high levels, say at 80-90 dB SPL. If you ...
Hilmar's user avatar
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1 vote
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ZP-OFDM vs. CP-OFDM channel equalization

Hint: you could convert zero padded ofdm into cyclic ofdm at the receiver, and use the same equalization. Though there will be more noise on this scheme. I had asked a puzzle some time back on this ...
Dsp guy sam's user avatar
  • 2,620
1 vote
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What's the computational complexity of MMSE equalizer in OFDM system

For a SISO channel, assuming you have estimated channel coefficients for each sub-carrier $k$, the MMSE equalizer is $$ \hat{h}_k=\frac{h_k^*}{|h_k|^2 + \frac{N_0}{\sigma_x^2}} $$ So you can see ...
jithin's user avatar
  • 2,263
1 vote

Is DFE equalizer always blind or can we use reference signal?

I can answer for adaptive filter containing feedback path alone as I have implemented it recently (both Blind DFE and with Reference Symbols), but it should work for DFE containing feed-forward path ...
jithin's user avatar
  • 2,263
1 vote

How to use matlab toolbox for 2qam dfe equalizer?

From the MATLAB documentation (https://uk.mathworks.com/help/comm/ref/comm.decisionfeedbackequalizer-system-object.html): "The equalizer uses the reference tap location to track the main energy of the ...
Engineer's user avatar
  • 3,042
1 vote
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Whitening Matched Filters for Equalizer

You are right that in scenarios where the channel is unknown and/or time-varying, we cannot implement a fixed matched filter. The first filter in the signal chain is usually an analog band pass filter ...
Matt L.'s user avatar
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1 vote
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Channel estimation and interpolation by vector in OFDM

You can use various methods to interpolate the channel - Linear, Polynomial, Sinc Interpolation etc. But what you need to keep in mind is synchronization. You have to make sure that frequency and ...
jithin's user avatar
  • 2,263
1 vote
Accepted

Frequency-specific Delay?

Yes it does exist and these are called "all-pass" filters in that over the band of interest the magnitude does not change (other than a possible fixed gain at all frequencies) but modify the phase ...
Dan Boschen's user avatar
  • 52.8k
1 vote

How to understand MIMO zero forcing as a bank of decorrelators?

It seems like you understand your question already but are unsure it is correct? Let the decorrelator be $\mathbf{D}=(\mathbf{H}^T\mathbf{H})^{-1}\mathbf{H}^T$, then the symbols post-decorrelator are $...
Engineer's user avatar
  • 3,042
1 vote

Programming a parametric equalizer - preventing clipping

kinda funny, i have never seen this post/question before and i was named in a comment, but because it wasn't quite spelled right, SE never notified me. using cascaded biquad parametric EQs to ...
robert bristow-johnson's user avatar
1 vote

Programming a parametric equalizer - preventing clipping

This looks like a graphic equalizer to me, not parametric, because the filter parameters are fixed. Changing your terminology might give you better results from a search engine. It also looks like ...
Dan Szabo's user avatar
  • 1,038

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