1k views

### Difference between bandpass filter and using fast fourier transform to extract power of frequency bands

In signal processing, I have heard of two terms: Using band-pass filter to extract some frequency bands. Using Discrete/Fast Fourier Transform (DFT/FFT) to extract some frequency bands. Are these ...
1k views

### How do I apply a binary mask and STFT to produce an audio file?

So here's the idea: you can generate a spectrogram from an audio file using shorttime Fourier transform (stft). Then some people have generated something called a "binary mask" to generate different ...
902 views

### Complex output after inverse FFT of a real signal

I have a real one dimensional signal s (light absorbance in a flow cell), which has significant noise and some periodic noise after performing a deconvolution of $S$ from $S_o$. Basically fft($S$) was ...
733 views

### FFT and IFFT : filtering frequencies

I am sampling at $30 Hz$. I have a sample of $N=150$. Here is an example of how my sample looks like, which starts at 54 and ends on 203 on the X Axis I am interested in observing frequencies ...
1k views

### Filter to add 3dB per octave?

If I want to add 3dB per octave to signal (e.g. to flatten out the power spectrum of an exponential sine sweep), is it really just as simple as... Take the Fourier transform of the time-domain signal,...
760 views

### Jack buffer size and FFT frequency resolution

In my actual Jack Audio setup (almost default values), Fs = 48kHz the buffer size is 1024 samples. I'm planning to do some filtering (lowpass, highpas, ...) and ...
857 views

### FFT frequency bands and filtering

I don't really understand FFTs, and filtering neither. I hope I can explain my confusion in a way that is not too confusing for you to understand. consider the following example: I have an EEG signal,...
508 views

### How do Anti-Aliasing Filters filter the signal?

I have programmed a anti-aliasing filter that uses the fourier-transformation and makes a perfect cutoff on my desired cutoff frequency for downsampling without aliasing. I have read about other ...
1k views

### Filtering on time or frequency domain?

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

### Easy Filter with FFT and Convolution

I'am pretty new to this topic so i dont have much experience with DSP. I want to filter(highpass) a WAVE file, i have already programmed the FFT, and now want to filter the FFT vector via convolution (...
645 views

### Removing frequency using FFT

So if I were to have an $n$ length sample of a given sample rate and were to run it through an FFT, resulting in $n$ complex elements. How would I obtain the frequency bins, such that if I know the ...
460 views

### Amplifying part of a signal

If I want to amplify a certain frequency in a digital signal, can I just take the FFT, increase the real part of the value for the frequency I want (leaving the imaginary part alone), and then take ...
730 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, ...
I'm working on a 10-second sound, sampled at 44.1 khz. I want to do filtering, and have a desired EQ (equalization) curve that varies over time, as suggested here (here $f0=250\ Hz$) How to ...