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,I'm doing an internship about mechanical maintenance. I have come to a problem that is a bit over my head. The problem was also discussed by a few process engineers but they did not come with a good solution.
So, the oil filter is part of a biogas compressor. The biogas comes from the...
Homework Statement
Digital causal recursive filter is a part of a digital signal processing system which has sampling frequency ##fs = 1200Hz## and is given by a differece equation:
where ##r = 0.9## and ##θ## is such that it filters out the spectral components at ##f = 200Hz##
Find ##H(z)##...
Hello,
I have a question about secondary ions entering a mass filter in Secondary Ion Mass Sprectrometry (SIMS).
We know that secondary ions are sputtered from surface of studied sample. Those secondary ions are entering a mass filter which sort them out due to their mass/charge ratio. After...
I am looking for an optical piece that can act as a mirror when the angle of incidence is close to normal (90 degrees) but acts as a see-through glass when the angle of incidence is less than 60 degrees?
Alternatively it can be a filter placed in front of a mirror that passes a lot of light at...
Homework Statement
Hello everyone, I have to implement a probabilistic data association filter with a particle filter.
I have already implemented a PDAF based on the Kalman filter.
The assignment considers a radar (range,angle) tracker. With the state s containing the x, y position and the x...
I get a ridiculous amount of gmail every day from my college's student body, but 95% is just students flooding the emails with nonsense ' forum bump' type responses and it's a chore to try and check my emails.
--Does anyone have any idea how to filter out or mute responses to future emails?--...
I have been trying to find out how the cutoff equation for the T section LC Lowpass filter is derived. I remember from college that f=1/(2pi√(LC)) for an LC circuit. But, with the T section, the cutoff frequency is given by f=1/(pi√(LC)), with L being the sum of the two inductors. My math has...
today I opened a package and unexpectedly there was a lot of tiny white pieces stuff flying out, like dust flying out from old books, but it's certainly not dust. I suspect it's paint pieces fallen from somewhere and don't understand how it gets to the package inside.
Could our nose and lungs...
I am desperately trying to bypass an internet filter that is installed on my computer
Basically I want to watch iPlayer and Youtube videos and I can't seem to get round it
Open to any suggestions
Dear forumers,
I need a 50hz 250VAC power line filter for an EMI shielding faraday cage. The filter should work between 100khz and 20ghz, attenuation should be >=60dB between 1mhz - 5ghz.
Regular power line EMI filters like this
don't seem to go that high (only up to a few hundreds of mhz...
I live in a small town and would like to make some observations today. However i don't have a solar aperture filter, i only have an eyepiece filter of which i do not trust. So is there any household items, materials i could use safely to save me from from ordering on the net and waiting...
Hello. I want to build camera for ultraviolet photography and reflectography. I plan to use debayer'ed backlit CMOS camera with or without Wood's ZWB3 glass UV filter. But I also need to find infrared cut filter because abudant IR radiation will ruin photos.
Problem is that there are plenty of...
My issue is related to the actual flow-rate I obtain when sampling air across a filtering membrane.
Each pump reports a nominal amount of air that it can draw in a certain amount of time (i.e.: flow-rate, like 10 liters per minute), but this is generally reported assuming normal temperature and...
When a non-polarized electromagnetic wave cross a polarizer filter, its intensity drops to a half. Then this now polarized wave cross a polarizer such that it has 90 degree compared to the other. The wave is completely vanished. But if we put another polarizer with, let's say 45 degree in...
Homework Statement
Homework EquationsThe Attempt at a Solution
I worked out the Bandwidth at: 1500Hz so therefore Fh should be 4050Hz and Fl should be 2550Hz
Could someone give me any tips as to how correct my key is? with respect to the Bode plot on the sinusoidal output of my design the...
I'm talking about nealy black plstic in front of some remote controls to add to my similar DIY device.
https://i.imgur.com/lmL4XN5.png
I found some plexiglass that does this (blocks visible light, let's NIR pass) but the thinnest is 2mm so I don't think it is usable for this because is...
Hi,
I designed a small wireless sensor that can run from 5V USB power. I use a USB hub to power my device via a USB cable. There is so much noise on the 5V USB line that my device readings turn inaccurate. Using the oscilloscope I can see noise frequencies of 10MHz and down to 100kHz, assuming...
Hi, I have an old system that outputs a stereo audio signal (using Left and Right RCA audio cables). However for some reason this system is also outputting a high-frequency noise on both channels regardless of its operation. At this point I think it would be simpler to build a simple audio...
Dears I have one question
When a filter gets clogged, the upstream pressure will go up. But what happens to the downstream pressure ? does it go down or stays the same in case of positive displacement pump vs centrifugal pumpThanks
In a typical resonant bandpass filter, resonance is set as none at 0 and full at 1, such that the filter rings infinitely at 1 and not at all at 0.
If there is a two-pole resonant bandpass filter, with an impulse excitation to a maximum amplitude of "1" and a resonance setting between 0 and 1...
Hello, I am learning about filters but I'm having trouble understanding what 'normalised' means and it's significance. I am using a LPF filter in a project and whilst there is software that will design it for you, I would also like to learn to calculate the values for myself and learn the...
In quantum physics they say that the probability P for a photon to pass through the filter depends on the angle Φ between the photon and the filter polarization axis:
P = cos^2(Φ)
And if I'm not wrong, when the photon passes through that filter (like illustrated in the image above) the...
Dear all,
I'm trying to combine the singals of both a hall sensor and a rogowski coil.
The proposed circuit is given in the following figure:
This should be the physical form of the implementation given in the following figure:
I can somewhat see a summing amplifier formed by A2, where the...
Homework Statement
For example, what type of filter is this:
How can one tell, as a general guideline, without finding the transfer function? I think finding the transfer function is the only real way to tell for sure, but what is a quick way to make an educated guess?
The Attempt at a...
Homework Statement
Identify the type of filter (kinds of frequencies the circuit filters out) analytically
2. The attempt at a solution
I believe the top filter to be an inverting low-pass filter, which passes lower frequencies and blocks higher frequency signals. I also think that the...
Hello, so this the circuit of an IdeaI OPAMP.
The Question is to find the function Vs/Ve .
I tried to make some sum ups to simplify it but I still unable to find a solution, so I tried to NOT sum up any component and found this:
E-S=iZ+i2(Z+R)
E=iZ+i3R
S=i2R
so the idea is to find E=f(i2) ...
I want to know about RC band pass filter ! more specifically details about the graph of voltage vs frequency..
how the curves goes up and why the curve goes down? I don't understand ...
please help me out
Hi, in determining the temperature of stars using colour index (U-B,B-V,V-R, etc), why do we need to use the appropriate pairs of filters based on their range of temperature? (this is what i read from wiki)
For cool stars, we use R-I, and for hotter stars, we use B-V. I don't understand how...
I use an Olll filter to view emission nebula such as the Great Nebula in Orion. What is the mechanism by which Olll in such nebula emit photons of the wavelength that passes through my filter?
Have built a 55 gallon DIY steamer from a DE pool filter. The pool filter is made from .06 inch stainless steel and was rated for an operating pressure of 50 PSI. As a pool filter, the vessel regularly operated at pressures of 10-15 PSI, and as much as 25-30 PSI when it needed cleaning.
Have...
Homework Statement
So I've been tasked with designing and band pass filter for my signals class. We're given the specifications that it needs to go from 200-5000Hz, and we need to use a kaiser window as the window function.
Homework Equations
There are 2 parameters, beta and N, given by these...
Hello,
I have been doing some research into the above filters and ran into a question. I saw a video that covered the pros and cons of each type of filter and it was recommended that a reactive filter was used at lower frequencies, the reason given was that the inductor that would be required...
Hi Guys
This question came up in the new supposed big thing in audio called MQA (Master Quality Authenticated). Here is a technical overview and a link to its patent:
https://www.soundonsound.com/techniques/mqa-time-domain-accuracy-digital-audio-quality...
Does EMI filter still work if you live near a base station which produces dirty electricity? Or EMI filter only filter the dirty electricity which would have been generated from your power circuit if w/o EMI filter?
Dear Community,
I want to use a Kalman- filter approach to calculate inclination angles (pitch and roll) obtained from accelerometer- and gyroscope- raw data. However the problem is that my sampling interval dt is not constant – it has a significant jitter instead. To investigate whether the...
i'm using http://ned.ipac.caltech.edu/ui/?q=byparams to extract redshift data. while I'm very happy there is now lots of data available, data requests need to be limited in size or you get an error. i would like to examine the patterns of redshift vs longitude, but that is too much data, i...
I have implemented the closed-loop motor control system as above in a Matlab simulation (pic Kalman.png). Here, the Kalman filter estimates the torque disturbance and angular speed of the motor and those are feed to the RLS algorithm for parameter identification, here it estimates the combined...
Homework Statement
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The filters of FIGURE 4(a) to (c) where designed using a commercial software package (http://focus.ti.com/docs/toolsw/folders/print/filterpro.html)
Write a report (of approximately 750 words) that discusses and compares the design of each filter in terms of their...
Homework Statement
[/B]
Select (with justification) from the op-amps listed in TABLE A those which are NOT suitable for use as the active component in the filter of (a) above.
Homework EquationsThe Attempt at a Solution
Currently The only Op amp I see that is not suitable is TLV2721 due to...
Hi, May someone helps me regarding this!?
i have a controller which will control AC motor as attached. in this controller, a stage comes where I need to use a Derivative Block before point 'B' as shown in the attached picture " controller block diagram" [...
HI,
i have a first order controller (ts/ks+k) which contain some oscillations and its settling time is very huge, i wanted the controller to have settling time of 10seconds and remove the oscillations. in order to remove the noise and get the expected settling time i added a filter ( s/cs+1)...
Say you were building a full-wave rectifier. How many simple ways (if any) are there to reduce the THD on the source caused by using a full-bridge rectifier load?
Also, If you used a low pass filter and then an isolation TX (or the other way around?), how much would that help to this end (if at...
Hi, All.
Given a scenario of a closed volume of volatile liquid and it's associated vapor above boiling point (ex. butane in a can at room temp.) which is dispensed through some tube or line:
Is there some filtering medium capable of ensuring that only vapor may pass through the line, producing...
Hi,
Out of interest, today I was mucking around with a 160W LED, 240V, 50hz, outdoor light.
I looked at the Power Factor (it was 0.96) and the THD was 14.something %.
I then wondered what would happen if I put a capacitor in parallel with the light. It was a three phase 90uF cap, so since they...
A nanofiltration filter has a pore size around 0.001 micron. Reverse osmosis filters have a pore size around 0.0001 micron.
Additionaly, reverse osmosis occurs when a semi-permeable membrane separates solutions of different concentrations so osmotic pressure has to be applied to move water from...
Suppose I have some sort of a filter, whose transfer function is given by H(w), where w is the angular frequency of the input signal in radians per second. I want to know the maximum value of the transfer function. If I solve for the resonant frequency w0, which from my understanding is the...
Homework Statement
Homework Equations
The Attempt at a Solution
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Which is the correct frequency response graph for this question? The first graph or the second one?
I have a signal that I am able to calculate through an acoustic model for airfoil noise. I am told that the model solves for a narrowband frequency response, however, my measurement data is provided in third-octave band representation.
How do I convert my current dataset to the third octave...
Hello everyone.
I'm trying to interpolate the data taken (frequency in Hz vs A in dB) from a bandpass filter with Q = 10.4.
The problem is that I'm not entirely sure about the transfer function that I should use to interpolate it. I'm trying to extrapolate the peak frequency, Q factor and...