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).
Hello, All.
I'm a student.
I have a problem. I need numerically calculate of the intensity distribution of the full coherent radiation in the spatial filter(cylindrical geometry) (Katron's scheme).
Input data:
Focal length of lenses F = 1 (m)
Length of the wave of radiation Lambda = 10-6...
What does the length of the filter in DSP means?
What does it refer physical or practical when it states that "signal transmission path models have long impulse response?"
And why do audio signal transmission paths have long impulse response?
Hi,
In the context of signal processing, I am curious about what's the relation and difference between system and filter? Are they the same?
Thanks and regards!
Dear friends,
I would like to know how can I remove an AC signal from a signal which is combination of AC+DC. AC signal 60V/50Hz DC=50V.
Please suggest me a C code or any algoritham or a filter which can remove AC signal completely and I should be able to see only DC...
help with filter design-urgent
hello guys I have to design a band pass filter for high quality audio crosoveer circuit.
following are the given condidtions
filter range : 3kHz - 20khz
stop band attenuation : 80dB/decade
distortion in pass band should be minimum
can someone tell me how to...
Consider a 2f:2f filtering setup with f = 1000mm. The system is illuminated with a uniform plane wave of uni amplitude and wavelength \lambda = 1.0\mum. The input transparency (object) has amplitude transmittance g(x,y) and the spatial filter has amplitude transmittance s(x,y).
Write an...
Hi everyone,
here is the problem:
I am trying to reproduce a human finger while pressing a keyboard.
I am using a shaker and a fingertip made of foam rubber. To measure the force history, a force gage make a link between the fingertip and the shaker.
The fact is the curve has an offset and...
how come more than one noth filter doesn't work. I Have three 60hz filters that have 12 db attenuation each when used one at a time but when I put them one after another in the circuit only the first works. all connections are proper I made the circuit many times because I thought I was doing...
Does an RL low pass and high pass filter need to have the same impedance in the circuit as to the source impedance to work properly. I put an inductor in series with the source with a resistor to ground as the low pass, and a resistor in series with the source with an inductor to ground as a...
We can easily design an digital filter with arbitrary amplitude-frequency response, but if we are required to use an analog filter to implement it, how to design? Any suggestion or reference to related paper would be appreciated. Thanks!
I'm having problems filtering out certain frequencies from others with a series LC filter. I have a 1.923 Henry DC filter choke inductor set in series with a 0.1 micro Farad capacitor. I send the signal through the inductor to the capacitor and output from the other side of the capacitor. I'm...
• No ripple can exist in the output, but non-linear phase shift is allowed.
• The frequency response must be as close as possible to the ideal filter response.
• Signals of frequency 0 ~ 5 KHz are only allowed to pass through the filter with a desired gain of 4dB . Other frequencies should...
Lease help me, I have an assignment that ask me Filter the nois of this function
f(x)=cos(0.1t) + noise
the noise is random number between -0.5< n < 0.5
Filter the noise out using the average noise method? ( in excel )
Thanks
In most of the EE textbooks I have, the topic of filter design seems to essentially be treated like "Here are some active filter topologies, and here are their normalized transfer functions, and here are a lot of tables of pole locations for say the 4 pole 1 dB Chebyshev filter. See you later."...
It may be a very simple question.
Why placing a blue filter in front of a light source will give blue light?Is this phenonmenon concerned with polarization of light(the vibration of electrons of the filter giving blue light)?
Thanks very much!
Hi,
I'm currently designing the ventillation for a number of pump stations for a large water pipeline. Essentially this will mainly involve forced air cooling, to keep the space within 5degress of ambient (i.e. no air conditioning).
My question has to with fan and and air filter...
Does anyone know the steps to design/ calculations of bandpass filter, linear phase FIR with these specifications?
a). N= 23 (number of taps) Freq sample = 10kHZ, Freq low= 2.2kHz, Freq high = 3kHz
b). apply a 23 tap to blackman windowing?
Any additional such as the comparison of the two...
Hi All,
I can't see how the following is proved.
Given two topological space (X, T), (Y, U) and a function f from X to Y and the following two statements.
1. f is continuous, i.e. for every open set U in U, the inverse image f-1(U) is in T
2. For every convergent filter base F -> x, the...
In a filter where 1/4 watt resistors is enough would the filter be less noisy if I use 1/2 watt or more or should I use the least wattage resistors needed?
Does anyone know how to filter 60 hz down to -140 db
all the notch filters I tried are about -60 db maximum but after I amplify the signal to 100db
the 60 hz becomes a problem again. I need a filter for this it doesn't have to be one stage and also I need the 100hz, maximum attenuation on 100...
Hello All,
For those of you who haven been following my last two threads, I finally decided to go with the Microcontroller/DDS combination to make my three-channel sine wave generator (since I have yet to find one in existence at all that doesn't cost megabucks).
I have the microcontroller...
http://img104.imageshack.us/img104/3557/1234uyq.jpg
Ok, there are a few calculations on this problem that I am having difficulty with. This is a past homework assignment which is why the answers are filled in. They are all correct.
Anyways I approached the problem in this manner:
V...
I have a predicament. I'm trying figure out the P-P ripple voltage of a Half-Wave rectifier filter, but the only equation I have is: I / (f * C) yet to find the current I need the DC voltage which I don't have yet. The same goes for the DC voltage. I have the equation: VDC = VOUT P – (VR...
Once again I'm going through all my old homework and taking the notes I should have done in the past, and I am stuck on calculating the components on a Bandpass filter. How would I go about this. I have the answers I just want to know how to find them.
Thanks...
By looking at the components in an AC filter how can you determine what type it is based on the following information?
The impedance of a capacitor at very high frequencies is low
The impedance of a capacitor at very low frequencies is high.
Inductors have a direct relationship with frequency...
Does anyone know the formula for finding the voltage of Vout at a certain frequency in a AC filter circuit?
I have a formula it looks like Source x (XL or XC) / Resistor + i (XL or XC)
I can get it to work for some but not others. I have a feeling it needs to be rearranged depending...
I have a 3 phase 3 pole inductive motor with a VFD that is tripping the breker even before it ramps up. The breaker is set to allow its inrush current without tripping.
There is about 400 feet of wire between this motor and its busbar.
After a load filter was installed for this motor...
I have a question which is to design a filter of the form:
y(n) = a(0)x(n) + a(1)x(n-1) + a(2)x(n-2) to remove a narrowband disturbance with frequency f0 = 70Hz.
The sampling frequency, fs is 280Hz.
I've made an attempt at answering it, but don't think my result is correct:
w0 = (2*pi)*...
1. Given equation:
y(n) = x(n) + x(n - 2) - 0.81y(n-2)
a) Find the poles and zeros
b) Determine its z transfer function
2. Z transfer:
H(z) = (SUMOF(a(m)*z(^-m))) / (1 - SUMOF (b(m)*z (^-m)))
[b]3. I get the feeling that this is pretty easy, I just don't know the required...
The question is to find the difference equation relating u(k) and y(k), which are input and output respectively.
H(Z) is given as
H(Z) = \frac{1+(1/2)z^{-1}}{(1-(1/2)z^{-1})(1+(1/3)z^{-1})}
Solution that is given:
y(k)-\frac{1}{6}y(k-1)-\frac{1}{6}y(k-2) = u(k)+\frac{1}{2}y(k-1)...
Is it possible to design a cable with properties (Capacitance and Inductance) to reduce the number of components needed for the PI filter? I know I can design a cable to have a specific capacitance and specific inductance, but I am not sure if or how i would get these to work with the pi...
Homework Statement
Hello everyone, I'm working on a summer project with filters (they're rather simple). Anyways, my professor suggested that I calculate flux through the final surface of the filter, which I guess is speed of water?
Long story short, I'm having a real problem with this... I...
I have built a LC parallel tank circuit, and I am having a problem with it. I have a ground that is placed between two polarized capacitors in series. With the positive leads grounded. And an output on the opposite of the input. The problem I am having is when I connect the ground the input...
i am making a tachometer which will count pulses from an inductive pikup connected to an HT lead on an engine. i am having great difficulty when measuring my signal from the pick up as there is a huge amount of noise. can anyone raccomend the best way to clean this up? someone mentioned an...
Hi all,
Here is a picture of two circuits.
The one at the left is stimulated with a current source and the other with a voltage source.
They give the same results V(1) = V(2).
Is it possible to say that the primer is a low pass filter?
Hi everyone - I'm trying to figure out this "tack hammer" method of determining the impedance and transfer function of an arbitrary length RCL ladder filter. This method is briefly explained in the second chapter of Wes Hayward's book "Introduction To Radio Frequency Design," however it is gone...
From a lab I am about to do:
"Pour 25.0 mL of nearly saturated solution of Ca(OH)2 into filter paper"
I am wondering why I would need to filter the solution (what a filter paper would capture). Isn't filter paper just good for removing solids. It is not even expected that all solution will...
I'm a senior student in high school requesting assistance and/or evaluation of a small-scale electrostatic filter for computer usage as a dust remover to prevent or mitigate build up of dust inside a computer.
Isometric pictures of the main parts are available.
It is basically an...
Homework Statement
I'm trying to work out the time domain response of a first order high pass RC filter, eg. http://en.wikipedia.org/wiki/File:High_pass_filter.svg
I've got two solutions, one using laplace and one using differential equations, but they are different. One equation must be...
I am playing with some accelerometer data and need to filter out the noisy output.
How do I implement a Low pass filter in excel?
I tried avg, rolling avg. They all smooth out the data but not what I want (averaged accn is finite when it is actually zero!)
If I can create an envelope...
Homework Statement
For circuit B on page 2, find:
a) the time domain response v0 for a unit step input
b) input/output transfer function T(s) = v0/v_in
c) plot v0 vs. time
d) plot sinusoidal steady state vs. frequency: the magnitude in dB and phase in degrees of T(s)
Homework...
Hey guys,
I have a question about the Bode diagram of a second order high-pass filter (one with both a capacitance and an inductance). The Bode-diagram of the amplitude looks like this.
http://dave.uta.edu/dillon/pspice/images/pst07g.jpg
Here, the cutoff frequency is equal to about 10 kHz...
Hello,
I am trying to understand how this graph http://en.wikipedia.org/wiki/File:Bandwidth_2.svg
gets plotted. My goal is to write a small program that takes the center frequency/bandwidth and a (cut/boost) gain values and plot the curve.
I initially assumed, all I needed to find was an...
Homework Statement
draw a circuit for a and pass filter using only capacitor and resistors that will transmit signals in the range 200-1500 hertz. if there are only 100 nf capacitors choose resistor values.
Homework Equations
The Attempt at a Solution
i know the circut would...
Homework Statement
I have to design a bandpass filter (300Hz to 3000Hz). I have been given a variety of resistors and capacitors to work with.
Oh yes, another thing is that i need an output voltage that's <8V. I'm cascading it with another IC.
Capacitors - 10nF, 0.1µF, 0.33µF, 0.47µF, 1µF...
Hey everyone,
I have a system that I know the x,y,z position and the alpha,beta,gamma euler rotation of an object in space at known intervals. I need to use a filter on this data to reduce the error of the measurements, and it would be nice to be able to predict future movement. I understand...
In filters usually you can find two different specifications: number of poles and dB/octave.
I know that the poles gives you the transfer functions using this equation for a low pass filter
H(f)=1/\sqrt{1+(f/f_{C})^{2P}}
Where P is the number of poles of the filter. But how can I translate...