A low-pass filter is a filter that passes signals with a frequency lower than a selected cutoff frequency and attenuates signals with frequencies higher than the cutoff frequency. The exact frequency response of the filter depends on the filter design. The filter is sometimes called a high-cut filter, or treble-cut filter in audio applications. A low-pass filter is the complement of a high-pass filter.
In optics, high-pass and low-pass may have different meanings, depending on whether referring to frequency or wavelength of light, since these variables are inversely related. High-pass frequency filters would act as low-pass wavelength filters, and vice versa. For this reason it is a good practice to refer to wavelength filters as short-pass and long-pass to avoid confusion, which would correspond to high-pass and low-pass frequencies.Low-pass filters exist in many different forms, including electronic circuits such as a hiss filter used in audio, anti-aliasing filters for conditioning signals prior to analog-to-digital conversion, digital filters for smoothing sets of data, acoustic barriers, blurring of images, and so on. The moving average operation used in fields such as finance is a particular kind of low-pass filter, and can be analyzed with the same signal processing techniques as are used for other low-pass filters. Low-pass filters provide a smoother form of a signal, removing the short-term fluctuations and leaving the longer-term trend.
Filter designers will often use the low-pass form as a prototype filter. That is, a filter with unity bandwidth and impedance. The desired filter is obtained from the prototype by scaling for the desired bandwidth and impedance and transforming into the desired bandform (that is low-pass, high-pass, band-pass or band-stop).
Hi everyone, I am recently starting a new project on designing a 2.4GHz microstrip bandpass filter, but there are so many ways doing this, which method is better for microstrip? hairpin-filter? interdigital filter? or combline filter?
Is there any website or material anyone can recommend which...
Hello I'm a beginner (Second Semester) at Electronics Engineering.
In the attachment is the image of the filter rectifier circuit that I am analyzing. My professor has given us questions and their solutions but for my full wave filter rectifier analysis the numbers are not the same.
The...
Homework Statement
I was asked to desing a RC passive high pass fiilter with a cutoff of 3KhZ.
Homework Equations
The formula for Fc = 1/(2piRC)
The Attempt at a Solution
I set 3kHz = (1/(2piRC)) but am not sure what to do next. Do I pick a random cap or resistor value and...
Cutoff Freq. = 1/2piRC.
Theoretical bandwidth = 5000 - 1000 (APP) = 4000
But when I do it practically Or simulate as in the pic
Bandwidth = 10000(Around).
I asked the teachers in my college they say I did the practicals wrong. Those teachers gave signatures to everyone in the class even...
hi.
in an FIR filter how do you remove the linear phase introduced by windowing?
also if the phase is non linear how can the distortion be minimized?
could someone please reply asap i badly need help with this. thanx
I'm working on a bandpass filter at 3.2 GHz. I built a few prototypes interdigital, pipecap cavity, and even microstrip.
Microstrip filter sort of works but it can't be tuned, so I abandoned it.
The other types also work, bandwidth and insertion loss is ok but they all exhibit garbage...
Hello all,
I'm currently taking an upper division circuits class as a MechE student after taking a 2 year break from the topic.
We were given a problem to find the transfer fuctinon T(s) of a high and low pass filter, and then plot Vout(t)'s phase and magnitude vs. the freq.
My question...
Coffee drains from a conical filter, with diameter of 15cm and a height of 15 cm into a cylindrical coffee pot, with a diameter of 15 cm at 2 cm^2/ sec. At a certain time, the coffee in the filter is 13 cm deep.
a) How fast is the depth of coffee in the filter changing at that time?
b) How...
Hi,
I would like to figure out the RC values for a low-pass filter to filter out the noise depicted in the attachment (the spikes). The ADC I'm using is capable of 250kSPS and I'm reading samples in a loop with very little processing between them. The noise seems to only exist for 2-4 samples...
hello every one :smile: i don't know if this is really the correct place for posting this question but here it goes!:wink: Can somebody tell me how the venturi metre and the filter pump work?
thanx in advance! :blushing:
Hi to all!
I have a little question for you. Does a b&w glass filter exist?
I now there are all kind of color glass filters, but I want to know if there are any possibilities to generate a b&w image without using your camera or your computer.
I know about the monochromator device, but it...
I know that purpose of the preemphasis filter in a noise reduction system is to increase the amplitude of the input signal at frequencies where SNR is low prior to transmitting the signal. I also know that a deemphasis filter is located at the receiving end and its purpose is to undo the effects...
given
t(s)= [2(s^2+9.32)] / [s^4+1.322s^3+0.976s^2+.750s+1]
how do you calculate the reate of attenuation increase in db per decade at high frequency?
Determine the gain in db at dc. To do this, just replace s=0 and then do 10log(result) right?
Also, at which freq is the attenation...
I've been asked to design a Kalman Filter where we can observe several states of a process (some of which being related to each other) and to use the Kalman filter to combine related observations to get a better estimate of each.
Some texts I've been reading seem to indicate instead of making a...
I want to ask the principle behind the RC circuit and LR circuit to become
Hign/Low Pass filter respectively?
How come RC circuit allow high frequencies to pass through but block the low frequencies,however vice versa in the case of LR circuit...
Hi,
Does anyone know how to design a 8x lagrange interpolation filter in matlab?
From what I understand, let say my input is
input = [1 2 3 4 3 2 1]
let say if I want to interpolate by 2, then I insert 0 between every
sample.
input_pad = [1 0 2 0 3 0 4 0 5 0 4 0 3 0 2 0 1]
then...
I'm not sure what I'm doing wrong here, as my answer does not match up with the books. Sorry about the scan, it looks kinda bad.
! I made a mistake writing the books answer down. It should be:
\bar G_v(j \omega ) = \frac{j \omega C (R_1+R_2)+1}{j \omega R_1 +1}
Any help would be...
Hi all,
I am trying to estimate the future location of a mobile device and I was thinking of using the Kalman Filter to do this. Problem is I don't really know where to start. All the literature I have been reading gets much to advanced to quickly.
What i have is basically, I am measuring...
Hey! I really need to find out how the width of the frequency band rejected depends on the resistance R of the following circuit:
http://img418.imageshack.us/img418/8168/rlc2wf.gif
I've done the following:
Q= \frac{\omega_0}{\Delta \omega}
so
\Delta \omega = \frac{\omega_0}{Q}...
Hey! I need to solve the following problem:
a) Show the trap filter below acts to reject signals at a frequency
\omega = \frac{1}{\sqrt{LC}}
http://img418.imageshack.us/img418/8168/rlc2wf.gif
b) How does the width of the frequency band rejected depend on the resistance R?
For...
hi
if anyone can help me solve this problem (T- type low pass filter)it will be appreciated. i have managed to find the current in the capacitor and form there on i don know what to do.
thanks
circuit of a resistive load is fed from a rectifier, via
a filter. The filter is designed to...
hi every one
i happened to have some junk tape recorders and amplifiers
so i set about making myself a deck with a cd drive
i have two tweeters two speakers but one sub woofer
i want a filter circuit so that i can take the left right inputs and get one bass input for the subwoofer.
and...
I was aksed to study and draw the transitions of narrow band-pass filter function gives as :
Av(s)=Ao (s*Wo/Q)*(1/(s^2+s*Wo/Q+Wo^2) ; S Laplace transform
where: Wo is central frequency
Q quality factor Q=Wo/WH-WL=Wo/BW
WH &WL are high cut-off and low cut-off frequency...
Hello,
I want to show my class how tonic water will fluoresce under UV light. My UV sources are a couple of 12V UV bulbs, as designed to "pimp out" (don't ask) a PC.
Here's the main problem: these also put out some visible wavelength, purplish light. I'd like filter this visible light...
Ok I am cleaning out my comptuer with some high pressure air... and i need a way to filter the air... and i need it now! I'm going to have big gusts of wind flying out of my computer full of dust and it don't want it to just all settle on my floor and on the furniture. save me batman! save...
Q: Derive an expression for the Vout/Vi, the ratio of the output and source voltage amplitudes, as a function of the angular frequencie W of the source.
The L-R-C circuits looks like this..
source(ac)----------capacitor-----inductor----resistor----(back to start)
Vout is taken...
(hopefully I posted this in the right place)
I am currently exploring the idea of creating a filter, with photographic application, that would allow for black and white images to be created without the use of black and white film.
I am basically wondering if this is in fact a...
Hi there,
I'm wasn't sure whether I should post this question in the maths section or here, but since this technique is used a lot in aerospace I thought I'd try here first.
I've grasped the idea of an ordinary Kalman Filter and created a program that tracks a noisy signal. However when...
Hey guys i was wondering something. When some product claims it has a filter that can filter out all but the smallest particles (like oxygen or H2O)... how can it do that? I mean i just imagine a huge grid of super duper tiny pins making holes only an atom or 2 wide... obviously that can't be...
Can anyoen name me a good spam filter (i.e. one that cuts out the vast majority spam, but doesn't get rid of genuine correspondace, even when that corresponadnce is not solicited).
Hello
I'm researching IIR filters: Butterworth, Chebyscheff 1 and Elliptic types.
I've been using MatLab to model them and analyse the responses. However, I'd like to know what these three filters are particularly suited to... i understand that Low-Pass filters are typically suited to...
i need to build a filter that will accept a 200hz square wave that will remove all harmonics other than the fundamental. there also needs to be an option to pass or block the dc value in the circuit. i understand the how to make the filter, but not the part about how i would have an option with...
In the diagram, Z1 and Z2 are the impedence of some combinations of L, R and C. The voltage input is placed across AB, and the output voltage is measured across CD. Z1 and Z2 can be designed to make the circuit a filter for output voltage V_CD. However, if we really place a load across CD, it...
I have this filter problem,
I am given a magnitude graph (magnitude vs frequency, with a point on it) of voltage across input current source and a sketch of a circuit: black box connected with a current source (cos(wt) and voltage across it is Vmcos(wt + theta)) and the question is to figure...
I need help in designing an active 2nd order low-pass Butterworth Filter that meets certain requirements.
The requiremetns are that it needs to be a minimum 2nd order coincident pole system design with a break frequency at 6kHz
and a minimum 40dB roll-off at the break frequency.
Hi everyone
Does anyone know how to design a 3rd order low pass Butterworth active filter with a cutoff frequency of 8khz ? thanks
p/s: Attachment below is what i have
[SOLVED] SCAF Solar City Air Filter (help!)
Hi people,
I am working on a this project, SCAF. It's a 3 part tower made of glass with filters around the short upright bottom section, the middle section is of laminated glass and slopes up to the top narrow vertical chimney section. PV panels are...
Im just trying to write a small introduction for my lab report due in on friday and while i have an idea in my head what it is, i just can't put in into words
I recently bought a Hydrogen-alpha filtered telescope (Coronado PST). Looking through it, the Sun looks mostly red as expected since the H-alpha filter only let's through visible light at a wavelength of exactly 656.3nm which is in the red part of the spectrum.
And I can see both lighter and...
I need help in cancelling microphone noise... I am just not sure whether or not i should use a lowpass filter... can anyone give me help?
i want to use the filter command along with fir1... but i don't understand how to use them... i couldn't figure out how to customize the filter...
can anybody help me design a low pass filter in matlab? its a simple task but i still have trouble filtering a wav file taken by recording using the sound card. i can't seem to get it right since the length of the input is variable... can anyone show me the right way to make a filter? thanks! i...
I want to get this solar filter for my telescope. It's the Solar Filter for Observer 60 Altaz & EQ model. It was made for the Observer, but I was wondering if it would work on my Celestron 60 AZ Model (refractor)?
The guide at the bottom says what model it fits, and obviously, only Orions...
I am putting together a control circuit for a DC motor. This motor requires 110 volts DC. It must be variable speed.
I happen to have a nice continuously variable transformer box that goes smoothly from 0 to 130 volts. This should take care of the speed variations.
I hooked this up to a...
Hi, I'm new into this subject.
I'm trying to understand how a low pass filter (where the frequency f is from 0 Hz to f_u ) for a speacker is working. The fuction for the low pass filter is \mid H \mid = U_out / U_in, that is
\mid H \mid = R / \sqrt{R^2 + ( \omega L )^2}
where...
sorry for my bad english, but this problem is translated from french. In this problem, i have to make a low-pass AM radio filter using the following information:
frequency: 130 kHz
Condensor Capacity: 12 nF
This filter must be installed in parallel with the synthesisor.
It says to use...
hi there
ive been attemping this question and i cannot find the equation to work it out anywhere !
any help would be great !
for a passive band pass filter
from the following list choose the three components which would produce a cut off frequency closest to 7 khz and a band width...