A finite impulse response (FIR) filter is a type of a signal processing filter whose impulse response is of finite duration.

learn more… | top users | synonyms

-1
votes
3answers
56 views

FIR / IIR and Wavelets

I am a self-learner of DSP by reading various books. I have accomplished basic understanding of Signals - CT and DT and a few transforms. I recently started to learn FIR / IIR Filters. The part that ...
0
votes
0answers
32 views

Using Python with scipy.signal firwin, how do I know how many taps/coefficients should be used?

I need to alter an FIR filter which I know very little about. I have a signal which need to be altered, and looking at a Python script used for this task, I see that it uses Scipy's signal library, ...
1
vote
0answers
53 views

Deriving finite impulse response for polylogarithm

As a part of my research i have to use the following z-transform in matlab 'filter' function so as to derive the convoluted signal from the original one. $$\frac{1}{{\rm Li}_{k}(z^{-1}e^{-b})}$$ ...
0
votes
0answers
23 views

high error in XOR problem of my Neural Network

i'm trying to implement a simple XOR problem with neural networks. Neural Networks are widely used in signal processing for prediction, replacement of missing samples, denoising, etc. The neural ...
0
votes
0answers
31 views

Backward propagation of error in FIR Neural Networks

FIR Networks are a really great kind of Neural Networks. It allows very precise predictions of missing samples for example when ones wants to reconstruct missing signals or adaptive noise ...
0
votes
1answer
57 views

Understanding IIR , Low Pass, High Pass, Chebyshev, Elliptic Filter? [closed]

I see these terms everyday in every lecture, I do read stuff from wikipedia, follow lecture notes, study solved exercises. All in all I do have a rough idea about these, I know a little from ...
0
votes
1answer
91 views

FIR-Decimation and Low-pass filter (taps vs number of input points vs number of decimation stages)

I am new to digital filters and trying to understand parameters behind them. Scenario I am trying to get DC value from signals sampled at 100kHz sampling rate. such high frequency is used due to ...
0
votes
1answer
40 views

Calculating Signal Approximation Error (Theoretical signal - Real hardware signal)?

I've got a FIR filter, which I developed in IC. Now, when I got my results, I ended up with two signals: Theoretical signal calculated through MATLAB as a response to my input. Real response given ...
0
votes
1answer
64 views

Creating a time domain filter from a frequency domain plot

In figure 11.23 of Monzingo's Introduction to Adaptive Arrays, the author uses a sinewave in the frequency domain to model the amplitude ripple in the passband of a channel of a receiver. What ...
0
votes
2answers
187 views

Bandpass Filter window length: filter “in phase” with sinusoidal input

Say you have a bandpass filter and you place it on 40 discretely sampled points from a sinusoid with a period of 40. Why is the bandpass filter (green curve on the image) only "in phase" with the ...
0
votes
1answer
49 views

Impulse Response from Frequency Response at Specific Values

I'm at a loss trying to answer the following question: The frequency response $H(j\omega)$ of a length 4 FIR filter with real impulse response has the following specific values: $H(j\cdot0) = 2$, ...
1
vote
1answer
145 views

How can I detect if a filter is FIR or IIR according to impulse response graph?

I have the following two graphs but I don't know how to recognize from the graph if they are IIR or FIR! Can you please guide me through? P.S.: Does MATLAB have a function to detect if an impulse ...
1
vote
3answers
126 views

Force Linear Phase for a FIR filter synthesized using Berchin's FDLS?

As a follow-on to this post, how would you force linear phase for a FIR filter you synthesized using Berchin's FDLS?
1
vote
2answers
117 views

Criteria to distinguish FIR and IIR filters from difference equation?

What criteria should be used to safely decide if it is an IIR filter or FIR filter from a difference equation? FIR filter are always stable, meaning all poles are inside the unit circle AND have ...
3
votes
0answers
112 views

Design Nonlinear (Arbitrary) Phase FIR Filter using Iterative Reweighted Least Squares (IRLS)?

How would you use the MATLAB function below to create a FIR filter with a custom magnitude and phase response? It is from the Statistical Modeling and Inference MATLAB Toolbox ...
6
votes
5answers
753 views

Why are FIR filters still stable even though they contain poles?

How come FIR filters are always stable? Since they contain poles, shouldn't they be more affected by stability issues than others?
0
votes
1answer
44 views

How to use IPP FIRGenBandStop method? [closed]

Following this link: http://software.intel.com/sites/products/documentation/doclib/ipp_sa/80/ipp_manual/GUID-5457048E-3C59-43E4-8A99-FB3873DCB769.htm I have produced the following code: ...
0
votes
3answers
272 views

Combining two FIR band-pass filters

I am using IPP for FIR filtering over 1D data. I want to use the same input and filter it using two band pass filters. This is how I do it: ...
0
votes
1answer
133 views

Noise Equivalent Bandwith of IIR and FIR Filters?

How do you calculate the noise equivalent bandwidth for an IIR or FIR filter?
0
votes
1answer
246 views

Gain of FIR/IIR filters

What are the formulas for signal and noise power gain of digital filters (FIR and IIR)? For a FIR, I've seen in Harris' windowing paper that the DC gain is the sum of the filter weights. $$ G = ...
2
votes
2answers
212 views

What is the meaning of the delay in a FIR filter

I'm using a C# library that has the FIR filter implemented and I'd like to know what's the meaning of the ${z^{-1}}$ operation (delay) mathematically. The triangle is multiplication, the circle is ...
0
votes
0answers
172 views

Sine-weighted moving average on non-periodic, stationary signal

I am looking for -or trying to create- a filter with a piece-wise monotonic second derivative in such a way that when placed on a non-periodic input signal, changes in sign of the second derivative ...
2
votes
4answers
366 views

parametric eq with FIR filters

Are there any good published approach for designing parametric EQs as FIR filters. The standard techniques discussed in DSP textbooks are frequency-domain-sampling or using Parks-McClellan, which ...
3
votes
3answers
5k views

FIR filter with linear phase, 4 types

I know there are 4 types of FIR filters with linear phase, i.e. constant group delay: (M = length of impulse response) Impulse response symmetrical, M = odd Imp. resp. symmetrical, M = even Imp. ...
1
vote
1answer
182 views

Calculating an impulse response in a stable environment

I would like to estimate the impulse response of a simple environment (room, two speakers, one microphone). I am aware of the issues/limitations of working with "near" LTI systems. That said, I have a ...
2
votes
1answer
101 views

How to calculate signal which is not changed by a filter?

Suppose that there is a FIR filter F and a signal S. The filtered signal is the convolution of F and S, F * S. The problem: how to calculate a signal S' such that F * S' = S' (the filtered version ...
4
votes
1answer
901 views

FIR design : compute coefficients for the same frequency response at another sampling frequency

I would like to know if there's a standard way to obtain the FIR coefficients for a sampling frequency $F'$ when the coefficients are for a sampling frequency $F$. I would like to implement the ...
3
votes
2answers
2k views

A Simple Lowpass Filter Behaving so Strangely

I don't know much about filter design. After reading a few articles on wikipedia I am playing with filter design and I see something weird and would like some help in understanding what exactly is ...
4
votes
2answers
467 views

Downsample Equiripple FIR filter

I am designing some Downsampling filters using the remez exchange algorithm (Matlab FDAtool). I see that some times i get a spike at the first and last coefficients. does anybody knows why is that? my ...
6
votes
1answer
731 views

Do FFT-based filtering methods add intrinsic latency to a real time algorithm?

In a current audio processing application, I am working entirely in the time domain using IIR filters. This is so I can use an audio buffer of just 3 or 4 samples and can guarantee that there will be ...
3
votes
2answers
335 views

With respect to the dirac delta function, what does $\delta [x + 2A, y - A]$

I have come across the following function and I'm trying to figure out what it really is. I have this function: $f[x, y] = \delta [x + 2A, y - A] - \delta [x - A, y + A]$. The $\delta$ is ...
7
votes
3answers
2k views

Downsampling lowpass filter for audio: FIR or IIR?

I'm working on a real-time audio processing project in which I have to downsample a 44.1 kHz to a yet-to-be-determined lower sampling rate essentially for reducing computational complexity. I'm ...
12
votes
3answers
531 views

How can I design a very narrow filter?

Suppose I've got an audio signal sampled at $48000$ Hz, and I'd like to design a low-pass filter that isolates everything below ~$60$Hz. In the digital world, this is a low-pass filter with the ...
12
votes
6answers
2k views

Where can I get an open source implementation of the Parks-McClellan optimal FIR filter design algorithm?

Background: Often times I am doing some sort of signal processing task that requires a unique filter. Usually at this point I go to Matlab and generate a new unique filter using firpm(). The Matlab ...