# Questions tagged [digital-filter]

A digital filter is a system that performs mathematical operations on a sampled, discrete-time signal

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### What are the challenges of designing high Q digital filters?

I am not familiar with digital filters and digital signal processing. I do know that implementing an analog filter with a high quality factor is not practical, because (please correct me if I'm wrong) ...
40 views

### Why is the prewarping not working as it should?

Just playing around with the 'c2d' command from matlab and trying to convert a continuous 2nd - order lowpass butterworth function to a digital one which has the specs of Fc = 20e3Hz and Fs = 44....
446 views

### Anti-Aliasing Filter example

I need help in solving the below question. Bandwidth of the signal is 1KHz. Use a 12-bit ADC with SNR of 78dB for sampling. the sampling frequency is 12KHz. Choose suitable filter order and cut-off ...
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### Digital filtering after analog to digital conversion (ADC)

I am making a PCB that receives a signal with a frequency band of 3-50 Hz and peaks of up to 10's of uV. I have implemented proper analog LP and HP (band-pass) filters and am using a 16-bit isolated ...
53 views

### Digital control stability for more than impulse response stability?

I have a digital control system which is described by the transfer function $$Y(z) = \frac{-\beta}{z - 1 + k \beta} X(z)$$ where $\beta$ is a real parameter I can adjust to modify the ...
118 views

### Same z transformed function, but different answers of inverse z transform?

Given z transformed function is E(z)=1/(z+4) I know there are several ways to get the inverse z transform of this function. use partial fraction E(z)=1/(z+4) E(z)/z=1/z(z+4) apply partial fraction ...
1k views

### Is this alternator W RPM input circuit ok and how can I improve it?

I need a robust and reliable way of taking a RPM signal from the W terminal of a standard automotive alternator. Most of the time the signal will come from a 12V alternator but there is a requirement ...
175 views

### Why use convolution for pulse compression in radar instead of correlation?

I have not understood the way to process pulse compression in radar signal processing. I think it's correct to use correlation for pulse compression, but I saw many materials about pulse compression. ...
104 views

### Software oscilloscope

I have been developing a C language software for software oscilloscope which is part of a control software. From timing point of view the software consists of two execution loops. The first execution ...
10k views

### Why should I use digital filters rather than simply manipulate signals in the frequency domain and then recover them into the time domain?

I'm quite a novice in signal processing and I know this question may be too broad. But I would still like to hear hints from experts. I was taught to use butter (...
731 views

### Linear Phase Response

In many cases, it is demanded that filters have a linear phase response (like in the case of FIR). Why is linearity so important? Why not a constant phase response, or anything else (any other shape)...
465 views

### How to pick correct filter for a given signal processing task?

I did a study on digital signal processing and I found many theories. But I don't know how to figure out which filter to use when I get a practical signal processing task. Is there a procedure for ...
189 views

### Predicting decay time of a resonant bandpass filter?

In a typical resonant bandpass filter, resonance is set as none at 0 and full at 1, such that the filter rings infinitely at 1 and not at all at 0. If there is a two-pole resonant bandpass filter, ...
193 views

### Efficiency of FIR filter in verilog language

Implementing a 4-tap FIR unity coefficients, is this code efficient in power and area ? ...
157 views

### Why does this part of an OLED filter light only when orientated correctly?

Note: The screen is an OLED screen. I had assumed it was LCD, therefore the post mentions it as such. I was disassembling a Samsung phone (GT-I9305) and was able to seperate the LCD into two sections....
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### How to amplify the output of a digital low pass filter?

I have used the transfer function of a RC low pass filter to design a IIR Digital low pass filter. $$H(s)= \frac{1}{sRC+1} ;First \space order$$ H(s)= \...
526 views

### Calculate cutoff frequency of a digital IIR filter

I have an ADC with 1 kS/s and would like to append a digital anti-aliasing filter to it as I have to downsample the data to 10 Hz. As it's on an FPGA and I don't have any multipliers, I thought ...
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### DSP Library not working in MPLAB X

I have to make a digital filter with a dsPIC30F4011 (I'm completely new to microcontrollers). I was reading the documentation about the DSP Library to figure out how to use it. I created a simple C ...
606 views

### FIR filter in dsPIC with DSP Library

I have to make a digital filter with a dsPIC30F, but I don't know much about it. I've read part of the documentation about the dsPIC30F and the DSP Library, and I found a page on Microchip website ...
148 views

### Filtering Audio Signals in MATLAB

I'm trying to apply a filter to an audio signal in MATLAB and having some trouble processing it. So far, I have a transfer function that describes a K-weighted filter, and I am able to create a bode ...
75 views

### Why do we need an (adaptive) equalizer when we have a matched filter at the receiver?

When both can perform the same task of reducing the effects of ISI, why use both and not just one at the receiver end?
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### Understanding digital filters, specifically their effects on time domain information, how to preserve the waveform of a signal being filtered?

According to Steven W. Smith, in his book: The Scientist and Engineer's Guide to Digital Signal Processing, when designing a digital filter, "Good performance in the time domain results in poor ...
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### Digital vs Analogue Filters From an Non-Audio Perspective

Recently I have been reading about the use of digital filters. By deriving the transfer function of the desired filter (in the s-domain) and multiplying holds (ZOH or FOH). What is the general ...
51 views

### Filter gyroscope's error from linear acceleration?

I need to use 3-axis angular velocity data for my application, but the gyroscope outputs angular velocity when under linear acceleration (not rotating). Is there a way to filter this error?