6k views

### Is a notch filter for 50 Hz without delay possible?

I am processing an EEG signal (2 kHz sampling frequency) from hardware and the built-in filter doesn't work as intended. FIR gives a delay, and IIR is unstable. The signal of interest is from 4&...
• 273
12k views

### What does correcting IQ do?

Some software (for example SDR Sharp) has a "Correct IQ" option. This is used to get rid of the DC spike in the middle of the display. What does this setting do to the signal? What is wrong with ...
5k views

### Why do we put poles close to the zeros in notch filter?

In the book I'm studying from "Applied digital signal processing - Manolakis" it says: The problem with FIR notch filters is that the bandwidth of the notches is large. A simple way to create ...
2k views

### Moving Average for Notch filtering

I have a periodic signal(ECG) with period of ~1 seconds. It does not have features that are shorter than 0.04 seconds. For removal of 60Hz, I thought instead of implementing a notch filter, doing a ...
• 263
3k views

### Filter design - Rules of thumb regarding ratio of sampling and stop/pass frequency

The issue: I have a signal in the time domain sampled at 51.2KHz. I want to apply a highpass filter with a pass frequency of 20 Hz. The problem: Using Matlab to do that, the design of the filter ...
4k views

### FFT analysis for Vibration Signal

I am working on balancing an air-spindle. For the unbalance analysis I use an accelerometer (NI device). I have the voltage signal from the accelerometer corresponding to the vibration of spindle at a ...
810 views

### Why a pair of complex-conjugate zeros provide a nulling filter? (FIR filter case)

FIR filter having a pair of complex-conjugate zeros that lie on the unit circle, with zeros of the form: $$z_1 = e^{j\omega_i}\qquad\text{and}\qquad z_2 = e^{-j\omega_i}$$ And transfer function:  ...
• 161
298 views

### DSP Puzzle: What network will create this waveform?

What network consisting of two unit sample delays, three multipliers (with constant gain coefficients), and three adders can we create to convert a square wave into the waveform as shown below: The ...
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1k views

### Remove square-wave pulse artifact

How can I remove a biphasic, square-wave-like artifacts from the signal, so I'll keep as much as possible information "under" the artifact? Below is the signal with artifacts: The artifacts are those ...
• 201
877 views

### Does FIR filter remove DC offset properly?

I was checking FIR and IIR filter for offset removal. But I found that FIR can not remove DC offset properly. I think there's something more to do with the filter coefficients of FIR to remove DC ...
804 views

### Specify notch bandwidth by pole placement

I am trying to implement a notch filter by placing zeros and poles. I found in this thread how to specify the frequency to be filtered out (referred to as $\omega_n$ in previous link,) but it is not ...
1 vote
1k views

### Zero-phase-shift filters must be symmetric about the origin

In reading Rafael Gonzalez Digital Image Processing, second edition, section 4.10.2, the author writes: Notch filters are the most useful of the selective filters. A notch filter rejects (or passes)...
1k views

### What kind of filter I should use to remove the oscillations in this autocorrelation function?

I have an autocorrelation function which is shown as following, I do believe these trailing oscillating wigs are spurious and should be removed by some kind of filter. But I am not familiar with any ...
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1 vote
1k views

### how to create a harmonic mask from fundamental frequency?

Using an algorithm that gives the fundamental frequency across time, example https://www.mathworks.com/help/audio/ref/pitch.html (or some other one?) how would I then use that, to create a harmonic ...
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