# Tag Info

### Does tsa function in matlab assume constant rpm in the same rotation?

The Time Synchronous Averaging (TSA) method was not invented by Matlab - they only implemented it. Therefore, I would ask if it is a good assumption rather than if it is a correct assumption. So, the ...

### Are resolution increase and noise reduction from oversampling mutually exclusive?

Your first point is true: if you oversample, your anti-aliasing low pass filter doesn't have to be as much of a "brick wall." The second point isn't exactly true. First of all, SNR and ...

### Is deep learning killing image processing/computer vision?

A deep network is an approximation function over a set of training examples. It is not a magic bullet. Picking the right training examples for a specific task is the difficult part. For example, I ...

### Meaning of Hilbert Transform

Hilbert Transform: If you have a sampled signal (equally spaced values of amplitude, of a time domain signal stored in an ARRAY), then the HILBERT transform provides the original timedomain signal (...
1 vote
Accepted

### How to interpret arg min in the the following equation?

$\arg\min$ is the argument of the minimum, in this case it is the value for $s_m(n)$ for each index $n$ that would minimize $|\frac{\psi_m^H}{||\psi_m^H||^2}y_m(n)-s_m(n)|^2$. This will result in the ...

### Order analysis on sample vibration data to detect unbalance in python

I think you are doing basically right, you can selectively add two more steps: (1) Check max order for a new sampling rate in order domain, make sure you avoid aliasing. (2) Add some flexibility to up-...

### Are there any order analysis functions in Python?

I am not sure if you can find an implementation to those functions (you might do if you will look long enough). Main point, each of those functions might be implemented in several lines so there is no ...
1 vote

### Standardizing signals from the same experiment setup with different recording tools

I don't think there is a "one size fits all" answer for this. Here is one possible process assuming that your goal is "if I measure a system with both tools I should get the same result&...
1 vote

### When is the Fourier transform of a periodic discrete signal $\mathcal{F}x[k]$ the same as $x[k]$ up to a diagonal matrix

tl;dnr version: No nonzero vector can satisfy the requirement stated in the body of this question. The rest of this answer is a long-winded proof of the assertion above. The Discrete Fourier Transform ...
Accepted

### What is the way in which an audio signal is "cleaned"?

for example to clean up wind noise signals? Wind noise is a relatively good approximation of white noise, i.e. noise that has the same power at all frequencies. So, by filtering the signal with a ...
1 vote

### When is the Fourier transform of a periodic discrete signal $\mathcal{F}x[k]$ the same as $x[k]$ up to a diagonal matrix

Let $\newcommand{\F}{\mathbf{F}_{{}_N}} \F$ be the (unitary) DFT-Matrix of size $N$. Let $\newcommand{\x}{\mathbf x}\x$ be the vector $\x=(x,\ldots x[N-1])$. Your equation says: \begin{align}\...

### The definition of Time Invariant systems

Both definitions mean "It doesn't matter what the clock on the wall says, the system always responds the same to an input." The definition where you're time-shifting both input and output is ...

### Laplace transform of derivative

The existence of $\mathcal L\{x*\delta'\}=\mathcal L\{x\}\cdot\mathcal L\{\delta'\}$ requires the same subexponential behaviour from $x$ (if $\lim_{|t|\to\infty}xe^{-st} \ne 0$, then $\mathcal L \{x\}$...
1 vote

### Transformation of the independent variable of signals

The independent variable denotes here any of the locations or indices at which $x$ is defined. The symbolic name or notation of the independent variable does not matter per se, as long as is a valid ...

### Transformation of the independent variable of signals

As per my understanding, $x$ is a function of $n$, Correct so it is not possible to write lets say $x[n-n_o]$. Why not ? The time variable can be transformed like any other variable so you can ...
Accepted

### Bandwidth of a given function

Good work thus far. First combine the two ratios with a common denominator using: $$\frac{a}{b} + \frac{c}{d}= \frac{ad + bc}{bd}$$ Then you can determine the magnitude using the relationship for the ...
1 vote
Accepted

### Find maximum of a square wave with variable frequency

An easy and robust solution would be to low pass filter with a post-processed "Zero-phase" filter, the result of this will be time aligned with the input waveform and provide an averaged ...
1 vote
Accepted

### Shift of the signal spectrum to the desired frequency

There is no allowance for transition band between the passband of interest (5.5KHz to 6.5 KHz less a notch in the center) and the frequencies in aliasing zones to reject based on the translation ...
Without any restrictions on $h$ you may build some very non real world cases. Especially if we're talking about the correlation function without the removal of the DC component. For instance, think ...