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 ...
- 31.4k
6
votes
Adaptive equalizer for IIR channel?
Note that the inverse of an FIR system is IIR, and the same is true for the inverse of an IIR system, unless it is an all-pole system, the inverse of which would be FIR. So in most cases the ideal ...
- 80.2k
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 ...
- 80.2k
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 ‘...
- 1,028
4
votes
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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 ...
- 657
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 ...
- 29.9k
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'...
- 16.9k
3
votes
Viterbi equalizer in a GSM system
Thanks for the answer. You are correct - the training sequence is known by the time you establish any communication.
In case if somebody stumbles upon this in the future, here's how to get this done:
...
- 61
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 ...
- 1,046
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 ...
- 13.8k
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 ...
- 37.1k
2
votes
Accepted
2
votes
Viterbi equalizer in a GSM system
From the referenced description and also from [1] it seems to me that the training sequence (here: midamble) is assumed to be known already. This knowledge has probably been acquired before in the ...
- 4,071
2
votes
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On the application of chaos in signal processing
A typical communications system is composed of the following parts:
...
- 10.1k
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 ...
- 31.4k
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 ...
- 26.1k
2
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 $...
- 80.2k
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 ...
- 1,046
2
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 ...
- 665
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 ...
- 80.2k
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 ...
- 386
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 ...
- 31.4k
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}...
- 5,760
1
vote
Programming a parametric equalizer - preventing clipping
There's no universally acclaimed correct design of equalizers. Just like there are multiple car designs per brand, there are also multiple techniques for achieving desired effects.
It's true that ...
- 26.7k
1
vote
Does zero-forcing equalizer need known channel impulse response?
You need an estimate of the channel to receive the sequence but the zero-forcing equalizer does not need the channel response as an input. The zero forcing equalizer estimates the channel response. ...
- 37.1k
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 ...
- 80.2k
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,...
- 31.4k
1
vote
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, ...
- 80.2k
1
vote
Accepted
Equalizer coefficients and channel coefficients
With a blind equalization technique like the constant modulus algorithm (which is often implemented using a least mean squares (LMS) filter as you indicated), you aren't directly estimating the ...
- 23.7k
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