# Questions tagged [digital-filters]

The tag has no usage guidance.

270 questions
Filter by
Sorted by
Tagged with
29 views

### Hydrophone signal calibration by frequencies

First of all excuse me if anything I post is completely or partially wrong (or poorly explained), I am new in signal processing and still learning a lot from this community, I will do my best to ...
89 views

### I can't wrap my mind around the concept of filtering and the unit circle ? any help? [closed]

Can someone elaborate this theory where there is a link between the stability of a filter and the zeros or nulls being on the unit circle?
26 views

### How to compute the DFE based MMSE equalizer FF and FB coefficients in a non adaptative way?

I seek your assistance, I am reading the Proakis 5th edition and I came across a paragraph explaining the tuning of DFE filters, i.e, how to compute the FF(FeedForward) and FB (Feedback Filter) ...
57 views

### Noise Reduction Moving Average FIR

I read that the noise reduction of a moving average FIR can be expressed as the square root of N where N is the length of the filter. How do you prove? I can't quite get it.
54 views

### How to match zero-pole diagrams to their frequency responses (Discrete Time)

I get confused when there are a lot of zeros/poles in the zero-pole diagram and I find difficulty understanding their frequency response. I know the following: 1. Complex conjugates cause double ...
23 views

### HF ionospheric Channel Model Example in matlab : Watterson model

In the example file in matlab HFIonosphericChannelModelExample.m, the watterson model is simulated. In this model the channel is represented as one tap (for the sake of simplification) delay channel. ...
51 views

### Filter response to sinusoidal input signal

This question is related to Does 46 dB gain of a filter for a frequency imply 200 times more amplitude? In the accepted answer it is mentioned that "For a sine wave input the amplitude of the steady ...
17 views

I'm currently working in a project as apart of a student team. Setup A platform is attached (placed over and screwed) two 1 Kg load cells in order to measure the weight of the system. A vibration ...
134 views

### Early-Late Symbol Synchronizer on Non-Triangular Pulses

I've been studying the basics of digital communications using the free book at desktopsdr.com. One of the examples is a 4-QAM demodulator which where symbol timing recovery is done with some Early-...
39 views

### How to re-program/modify sound frequencies without DSP processor?

I'm developing a mobile application that controls Bluetooth sound-speaker functions, which includes an equalizer to modify the output audio frequencies. The audio processing module on the speaker ...
66 views

### how to stop matlab from rounding my values and keep them at same precision during calculations?

here are my IIR coefficients: CoefIIR=[1.630078934734 1.267893338385 1.112390120011] and here are the result given to me by matlab commands: ...
35 views

### std::cosf fluctuation: Results are off in low frequencies [closed]

I attempted to generate a continuous wave signal by using the C++ cos/sin functions. It's partly successful, meaning high frequencies seems ok, but very low frequencies give unexpected results. The ...
51 views

### Modeling audio effects, reverse engineering

Okay so I'm relatively new to signal processing and don't know the specific terminology to help narrow my search, but I'm looking for advice in the form of books, papers, references, etc that can help ...
152 views

### Choosing Right Type of Filter for time series data

I am working on a temperature time-series data which is very noisy. I am trying to measure true low and ...
29 views

### Design of frequency sampled filter in matlab

I have written following matlab code for frequency sampled filter: ...
54 views

### Digital Tanlock carrier recovery loop

I’m currently trying to understand a digital tanlock carrier recovery loop for QPSK (for example) I cannot understand how it works. For example we an ideal QPSK constellation. phi = atan2(Q/I) = pi/...
106 views

### What is the slope of a transfer function?

Lets say I have a Transfer function (H) plot as below. I need to find the SLOPE of the transfer function in dB/MHz. That is... i need a plot (db/MHz) vs frequency. How can i go about it ? ...
225 views

### How determine the delay in my signal practically

I am trying to practically determine filter group delay so that I can try to reduce or adjust for it. I have tried all kinds of methods but still can't get the right result. I know that theoretically ...
160 views

I want to design a receiver for a spread spectrum system. I know that two Pseudo sequence with two different length must be used in the receiver, but I can' t manage this with common receivers(such as ...
190 views

### Relationship between wavelet shape and wavelet filters

MATLAB has a library of wavelet functions, showing their "continuous forms" as well as the the decomposition and reconstruction filters. In decimated wavelet transform the filter size remains the ...
36 views

### Parallel form filter design

I have a transfer function coefficients as following: [b,a] = ellip(4,.2,40,[.41 .47]); I'd like to factor this system into its PFE using ...
42 views

### ROC and impulse response

For the LTI system given below, there are three regions of convergence. $$H(z)=\frac{5-3z^{-1}}{1-\frac53z^{-1}-\frac23z^{-2}}$$ a) Find all possible regions of convergence for this filter. b) For ...
34 views

75 views

### Calculate transfer function of two parallel transfer functions in a feedback loop

I have rational transfer functions: $$H_1(z) = \frac{ b_0 + b_1z^{-1} + b_2z^{-2} }{a_0 + a_1z^{-1} + a_2z^{-2}}$$ $$H_2(z) = \frac{ q_0 + q_1z^{-1} + q_2z^{-2} }{p_0 + p_1z^{-1} + p_2z^{-2}}$$ And ...
309 views

### How to filter data with given numerator and denominator coefficients of an IIR Filter, in MATLAB Implementation

Coefficients are: b = [9.02201251375918 0.485095309463300 -0.571759308660462 3.63774928924158 4.42592447788520 1.30093840271037 -0.898592924453941 -9.08965268561448 -12.4939309921467 ...
39 views

### Bringing the signal into the same level [duplicate]

I have a signal, shown in the attachment (blue one). As you can see that the latter part of my signal has a higher dc offset. I want to bring the signal into the same level. I have tried eliminate the ...
245 views

### Determining window Size for Savitsky-Golay filter (Savgol_filter)

First, I am aware that an ideal optimal window task is really signal/task-specific, i.e. nature of signal/sampling rate/characteristics of interest etc. What I am interested in: "Is there an optimal ...
58 views

### Downsides of higher order filtfilt's

I understand that with a standard filter, higher order will yield sharper frequency selection at the cost of increased phase delay. However, with so-called zero-phase-distortion filters like that ...
126 views

### MATLAB fir2 - npt and lap

This might not be the right place to ask this, but I'm hoping someone can explain two of the arguments in the MATLAB fir2 function. It is a function for designing ...
204 views

### Reverse engineering a digital filter

I have 2 simultaneous signals that both are designed to measure eye movements. They are sampled at 250 Hz. We have 12 subject recordings. For 3 stable periods in each subject, we choose 256 points and ...
65 views

### What is the threshold to prefer polyphase channelizer over FIR filtering?

A wideband signal need to be processed to extract several narrowband channels from it. There are two straightforward approaches to do so: For each narrowband channel shift frequency and filter it ...
355 views

### Numerically Stable IIR filter

I am making an IIR Filter and I am running into problems with stability with higher orders. The values go off to infinity as soon as it starts. So far, I've been using MATLAB to generate my filters ...
108 views

### Adaptive Band pass filter for extracting respiratory waveform from accelerometer data

I am recording data from an accelerometer attached to the chest (1000Hz). I need to extract the respiratory waveform. I tried an adaptive bandpass filter based on a dominant frequency in my signal ...
1k views

### How to design a digital filter in python that will run over an uC?

I am trying to implement a digital filter over a uC (it doesn't really matter which filter and which micro controller because I'm looking forward to learn how to do it in the future with different ...
21 views

### Converting the equalizer coefficients from VSA at 2 sample/Symbol to 1.5 sample/Symbol

I was looking for some feedback on conversion of equalizer/filter coefficients at different sampler rate. Problem Statement: We have built a transmitter system whose output is at 1.5 sample/symbol (...
71 views

### Where can I find information about how to implement IIR filters on micro-controllers?

I am trying to implement an IIR filter on a LPC1769 (I don't know if it's relevant). I already have the H(z) so all the design part is prety much solved. What I am looking for is information about: ...