9
votes
Accepted
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 ...
- 42.5k
5
votes
Accepted
Given an FIR filter coefficients, how can I find coefficients of its equalizer filter?
Assuming that you also want to equalize the filter's phase response (not only its magnitude response), you need an equalizer with a transfer function $E(z)$ that is the inverse of the FIR filter's ...
- 88.8k
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 ‘...
- 1,038
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 ...
- 537
4
votes
Accepted
Design of equalizer for wireless communication
Ok, there is some misconceptions in your question. I strongly recommend you to read a little more about the topics, but I will try to help you a little. My answers and some comments:
...linear ...
- 677
3
votes
Accepted
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 ...
- 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 $...
- 88.8k
3
votes
Accepted
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'...
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 ...
- 31.7k
3
votes
Accepted
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 ...
- 1,056
3
votes
Accepted
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 ...
- 14.9k
3
votes
Accepted
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 ...
- 48.8k
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 ...
- 29.6k
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 ...
- 29.6k
2
votes
Accepted
Matlab: Help in applying equalizer and proper calculation of symbol error rate for QAM modulation in Rayleigh channel
Let's take a look at the cost function of CMA:
$ J(\mathbf{w}) = E[|y_{k}^{2} - 1|^{2}] $,
onde $ y_{k} = \mathbf{w}^{H} \mathbf{x}_{k} $ and $ \mathbf{x}_{k} $ is the filter input.
It says that ...
- 677
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 ...
- 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, ...
- 88.8k
2
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 ...
- 42.5k
2
votes
Accepted
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 ...
- 88.8k
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 ...
- 396
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 ...
- 42.5k
2
votes
Accepted
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}...
- 6,080
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 ...
- 3,012
1
vote
Accepted
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 ...
- 88.8k
1
vote
Accepted
Linear Equalizers Weights
In an initial phase, the training sequence is used to determine the optimal equalizer weights. There is usually no reason to leave the weights fixed because you need an adaptation algorithm to compute ...
- 88.8k
1
vote
Linear Equalizers Weights
The error should be minimized between the equalized signal and what? There is no known sequence in this case.
But there is: if the channel is still good enough so you can decode a packet successfully,...
- 42.5k
1
vote
Accepted
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 ...
- 2,213
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 ...
- 48.8k
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 $...
- 3,012
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 ...
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