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1500 questions
9
votes
1 answer
Compensating Loudspeaker frequency response in an audio signal
I have been working on a project in which I was required to work on the audio signals recorded from the loudspeaker kept in front of a filter. So, to simply explain it:
$$\boxed{\rm LoudSpeaker} \longrightarrow \boxed{\rm Filter}…
Styal
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9
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3 answers
Frequency resolution of DFT
I know that the frequency resolution in a DFT is given by sampling rate upon the total number of samples. $$\Delta f = \frac{f_s}{N}$$
But, what I want to know is where does this relation comes from? Or What criteria(like Nyquist criteria limiting…
Rhinocerotidae
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9
votes
1 answer
Plotting the magnitude response of a biquad filter
I've put together a multi-band audio EQ using biquad filters. I'm getting the coefficients using the methods from the RBJ cookbook.
Now I want to plot the curve showing the magnitude response. I'm using an equation from this source
Here is my…
MVTC
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9
votes
2 answers
How to estimate the number of taps needed for subsequent channel estimation algorithms?
I recently implemented an MMSE channel equalizer, and I have read about many other types of channel estimation/compensation algorithms out there. However, one thing that is never talked about it how to estimate the number of taps in your model of…
Spacey
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9
votes
2 answers
How to measure a lung nodule in a CT Scan DICOM image?
In this question, I would like to focus on intensity value of the CT Scan. First, take a look at the image below:
The upper image is the original image, while the lower image is the thresholded version. In order to measure volume of any shape,…
Karl
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9
votes
4 answers
Do we use closed loop or open loop information in Bode plot, Nyquist plot and Root Locus?
When analyzing a control system via Bode, Nyquist and Root-Locus, are we using open or closed loop information? I'm not able to understand when the poles of the open loop are used and when the one of the closed loop are. I think that what interests…
Tendero
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9
votes
2 answers
What is a $BT$ (Bandwidth-Time) product with reference to modulation?
I would like to know what does Bandwidth-Time product mean. I understand that Bandwidth ($B$) = 1/Symbol Time ($T$), hence $BT = 1$.
But how can it vary?
What is its significance?
e.g. When we say GFSK is GMSK when $BT = 0.5$, what does that mean…
eecs
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9
votes
1 answer
Large spike at the center frequency when using Ettus X310
I am using the Ettus X310 SDR and GNU radio. On the GNU radio schema I have a standard UHD USRP source block connected to a GUI FFT sink - basically I'm just displaying the spectrum of the raw signal from the device.
Parameters for the USRP source…
Tihomir Meščić
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9
votes
2 answers
Can a narrowband beamformer be used for speech separation
In my master thesis I am trying to implement a beamformer.
I've already done the delay-sum part 1 year ago. I have been told:
in FIR filtering we can do
FFT --> null the unwanted frequency bin --> IFFT .
We can to the same in beamformers. If we…
Kadir Erdem Demir
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9
votes
5 answers
What's the meaning of a complex zero/pole?
I have been studying signal processing and control for a while now, and I use Laplace and Fourier transforms almost everyday. Also another tools such as Nyquist or Bode plots.
However, I had never thought of this until today: what is the physical…
Tendero
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9
votes
3 answers
Extract Sine Phase and Amplitude - accurate and robust method
This is a followup question to one I asked earlier based on the chat after the answer given by @hotpaw2, and cross-posted from stackoverflow since it was suggested it is more relevant to DSP. I have a signal which will be a single cosine wave, with…
KBriggs
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9
votes
2 answers
Why is Gaussian noise called so?
Can you please explain: why is a specific type of noise called "Gaussian noise"? Why is it relevant to call it Gaussian? Please, explain in layman's terms.
user18425
9
votes
4 answers
Zero, First, Second ... nth-order Hold
The rectangular function is defined as:
$$\mathrm{rect}(t) = \begin{cases}
0 & \mbox{if } |t| > \frac{1}{2} \\
\frac{1}{2} & \mbox{if } |t| = \frac{1}{2} \\
1 & \mbox{if } |t| < \frac{1}{2}. \\
\end{cases}$$
The triangular function is defined…
Mark
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9
votes
5 answers
Why Do I Get This Crackling Noise on Zeroing out the High Frequencies?
I recently started playing with the Fourier transform (after spending a few weeks learning about the mathematics behind it). I decided to try hacking together a low-pass filter on the following sound bite:
In particular, I took the Fourier…
JeremyKun
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9
votes
2 answers
Filtering a digital signal online in real-time using python
I am currently trying to apply a bandpass filter to a signal in real-time. There are samples coming in with a constant sampling rate and i would like to calculate the corresponding bandpass filtered signal.
What would be the best way to do this? Do…
BStadlbauer
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