30 views

### FFT/PSD/IFFT analysis on single axis piezoelectric accelerometer signals for curb impacts

I'm trying to denoise the signal by performing PSD analysis and followed by IFFT. Ultimately, I want to generate Force and Displacement plots from the denoised acceleration signal. Noisy Acceleration ...
44 views

### Time Series processing using fft

I have a set of real data (timestamp and value) with an unstable step between samples (5sec, 30sec etc.). The data is the % of fillage of a vehicle's tank through time. Due to the harsh volatility of ...
774 views

### Curved noise floor and ugly unexplained peaks after FFT

It has been so long since I studied this at University, so I'll better ask here if I'm doing something really wrong here. I'm using a USRP frontend for L1 band surveillance. I want a 20MHz bandwidth, ...
208 views

### Zero padding issue - cut the buffer

I have some issue with zero padding. It's probably because I don't understand it enough. I have buffer size set to 400. And I use radix-2 fft. So I take the input signal 400 samples, and add to them ...
2k views

### MATLAB : How to filter a data signal

I have a data signal (column vector) with N values taken over at specific sample rate (dx) at a fixed frequency. After taking the Fourrier transform of this signal and representing it in the Fourier ...
49 views

### Find signal power in a band by integrating the PSD in a frequency band (and zeroing the out-of-band DFT bins)

I know that directly zero DFT bins outside a frequency band has the side effect of introducing ringing, as this post says Why is it a bad idea to filter by zeroing out FFT bins?. But what about ...
43 views

### Using DFT Rotation for Frequency Down-Mixing

Is it possible to perform Frequency Down-Mixing (sometimes referred to as Down-Conversion) by simply rotating the DFT sequence? If so what are the Advantages and Disadvantages of this method?
117 views

### How many things can they be done with a spectrogram?

I found some things that can be done with a spectrogram. filter frequencies by setting the bins to zero observe what frequencies make up the signal. observe the energy or amplitude of each frequency, ...
24k views

### Why do we use window in time domain rather than do FFT modify the spectrum and than inverse FFT

I thought that DSP would be done by using FFT of portions of a signal, modify the samples that result from FFT (since they represent the spectrum of our signal + noise) and remove any unwanted signals ...
60 views

### How can I generate an ideal 2D low-pass filter in MATLAB?

I've been tasked with creating a 32 x 32 half-band low-pass image filter in MATLAB. My thinking is to generate the ideal filter mask in the frequency domain and compute the corresponding convolution ...
31 views

### filtering difference b/w freq and time domain

When you want to get the specific frequency (ex. around 1000Hz), you might take FFT, remain the frequency you want, and reduce the power of the other frequencies you do not. ex.) if fs=16khz and ...
100 views

### Time domain to frequency domain conversion of audio signals to extract 1/3 octave frequencies

I am writing first time in this forum and I am not expert in programming and FFT. We have developed an android app (Noise Tracker) for noise measurement using smartphones. It displays noise levels in ...
1k views

### Filtering on time or frequency domain?

I'm applying an ideal filter on the frequency domain. My code below: ...