# Questions tagged [digital-filter]

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

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### Digital Signal Processing vs. Analog Signal Processing for 100kHz DAQ project

I have a dumb question to ask (for a lot of you) but it has been bugging me for a while and I need someone who can give me a clear answer... (I'm a second-year in electrical engineering) So, I am ...
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### Filter signal on oscilloscope using math functions

Is there a way to do a time domain low pass filter, in software, on a Siglent SDS2000X Plus series oscilloscope using these math functions? The ones that stand out the most are ...
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### Adaptive Particle Filter: unknown process Equation

In my design and implementation of a SIR particle Filter, I don't have the state process equation of the actual system, which would have given a very good estimation of the real signal. I was ...
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### decimator circuit using dflipflops

I am studying about DPLL. There are questions among CDR papers written by the same researchers. Is the symbol likes step symbol after Adder a quantizer? The output of Decimator by factor 2 is -1,0,+1 ...
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### Laplace of third-order lead-lag filter

For Butterworth low-pass filters, the Laplace function of the third-order filter is $$H(s)= \frac {1}{\left(1+\frac{s}{\omega_c}\right)\left(1+\frac{s}{\omega_c}+\frac{s^2}{\omega_c^2}\right)}$$ ...
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### How to implement digital filter that will attenuate the voltage over certain ranges in my voltage-temperature plot

I have a temperature sensing circuit that has a "somehow linear" output voltage over the range 20-80 °C. I plan to use an 8-bit ADC to have a digital representation of the voltages. However,...
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### Is there a way to convert a time delay into a sample delay?

I have been given a time delay of a signal and the sampling frequency, however, I am trying to calculate the delay in samples. My logic is: delay frequency divided by sampling frequency, however, this ...
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### Digital filters that can be applied to both static and dynamic measurements

Is there a digital filter that can be applied to both static and dynamic measurements WITHOUT changing the parameters of the digital filter? For example I made a temperature measuring device that can ...
205 views

### Creating a digital PLL

I want to drive a quartz crystal resonator at its resonant frequency so I need to stay locked on to its resonant frequency as its resonant frequency changes. I'm using an FPGA to do this. I want to ...
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### IIR digital filter: samples not matching the frequency response

I am working on a small project in Mathematica involving a Chebyshev 4th order highpass filter, trying to obtain its digital IIR filter with the bilinear transformation. I implemented the differential ...
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### Apply S-Domain Notch to Time Signal

I have a signal in time domain which shows an 8Hz oscillation. I've designed a notch (band-stop) filter in frequency domain (S domain) to filter this 8Hz oscillation. Notch design parameters are Width,...
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I looked through lots of questions, but I didn't find a suitable answer for the project I'm working on. The project can be thought of as a simple control box, water valve, and scale. The mcu control ...
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### How to identify low pass, high pass, band pass, and band stop filters?

I'm taking a course dealing with signal processing which includes filters. In a certain task I got these two filters h and g: These parameters are given: A1=159 A2=138 theta C = 0.26pi N=337 Both ...
1 vote
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### How to properly implement an IIR High-Pass filter with a cut off frequency ~20Hz

I am trying to implement a digital High-Pass filter (IIR) with a cut off frequency around ~20Hz on a STM32H753ZI with the CMSIS DSP API. Every time I try to go test it, the output is no longer ...
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### Why using a pi filter when the applied voltage is DC?

We had to simulate this circuit for an assignment but I still don’t understand why c1, c2, c3 are used in this converter. Are they used as a filter?
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### MATLAB filter designer giving out filters with huge DC gains

hope y'all beings safe out here and doing well. I am trying to create a single stage biquad (2nd Order) butter worth filter using MATLAB's filter designer tool. Just to see, I tried plugging back the ...
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### Simple low pass digital filter implementation for non-uniform sampling?

I have a system sampling an analog input and I want to filter that value using a simple, first order filter. EG something of the form: Yn = A*Xn + B*Yn-1 However I have no control over the ...
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### DC filtering for digital audio amplifiers

I am working with digital amplifiers and from what I can see there is a DC blocking filter that is placed at the start of the signal chain. Why is this DC filter placed at the start of the signal ...
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### Filter for rotary encoder

I'm attempting to use PID for DC motor control. The motor is geared, with a magnet on the motor shaft coupled with a single hall effect sensor to help measure speed. This is all wired up to a capture ...
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### How to draw SPL curve for a parametric equalizer?

I want to show (graphically) the Gain/Attenuation vs frequency of a parametric equalizer. This is my circuit: https://sound-au.com/project28.htm The same schematicas as a screenshot: I want to show ...
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### Low Pass filter using Parrallel components

I have a PCB design that I need to add a low pass filter. However I can only add components in parallel. It is going to be very difficult to cut the tracks or add components in series. Is there any ...
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We usually cascade filters in ascending Q-factor to avoid saturation in each individual stage. But are there advantageous situations when we cascade filters by descending Q-factor?
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### Exercise relating to FIR filter [closed]

I was trying to resolve a problem from "Understanding Digital Signal Processing". I have some questions about it. Why do we need to redesign the filter if we find out that the sample rate is ...
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### Truncation noise in digital circuits

I was reading a chapter of my book (I am not putting it as reference since it is not in english) about the quantization noise problem in digital filters. Specifically, it writes about a filter that ...
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1 vote
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### "Order" of a digital filter (FIR and IIR)

I have some doubts about the meaning of order for digital filters. All I'll put here is taken from these slides. 1) Let's start from the definition of FIR filters: From this definition we see that ...
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### Physical operations of discrete - time circuits

I have a basic doubt about discrete time circuits. A discrete - time signal is a sequence of values which are taken at specific time instants (let's call them sampling instants), as we can see from ...
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### Doubts about IIR filters definition and transfer function

I have some basic doubts about IIR digital filters. My first question is about its definition. IIR means Infinite impulse response, so my question is: is it physically possible to realize such ...
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1 vote
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### Converting an analog Butterworth filter into a discrete filter

Here again to ask about another question. This time asking how to convert an analog transfer function to a discrete transfer function using standard continuous to discrete methods. The application ...
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### How can I design a low pass filter using Z transform in Microcontroller?

I have generated a signal which is a mixture of 50 Hz and 250 Hz sine waves using a microcontroller and DAC. Check the screenshot of the excel file: The values of row 4 (i.e. f1+f2) are feed to an 8-...
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