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 guys :)
I'm designing an automatic soap dispenser, in which the soap particles contain phosphors. These will emit visible light in the presence of UV light. I intend to have a small UV light source underneath the dispenser.
Thing is, its really bright in bathrooms, and its tricky to see...
Hello guys,
I just came out with a new idea for my thesis project which is to improve the air filter system (drop-in type).
Currently I doing some basic analysis based on the current stock air filter before I proceed to my prototype air filter system.Says, I've been given an air filter which...
what is the unit step response of a high pass RC filter ?
I want to calculate using transfer function approach.
My solution :
Y(s)/X(s) = RCs/(1+sRC)
X(s)=1/s
Y(s)=RC/(1+sRC)
taking inverse laplace transform we should get
y(t)=exp(-t/RC)
But if we consider Y(s)=RC/(1+sRC)
RCsY(s)...
Lets assume I have a signal that exists in time and it has an unit impulse at t=5, I only want to filter out that portion of the signal. So I plan to design a passband filter to filter the signal out at t=5.
This is where I get confused, my passband filter exist in frequency so how is that...
According to me Transfer function will be G(s)= (s2+2ζωn+ωn2)/((s+p1)(s+p2))
I assume from the given plot that ωn < p1 and ωn < p2
Then the bode plot will be as per me like following :From the Bode plot we can see for higher freq magnitude is amplified . So it will be High pass Filter.
That's...
I'm stuck on a really simple problem because I haven't done MATLAB in a while. I have transfer functions for nth order lowpass Butterworth Filters:
H(jw) = 1/(s + w_c)^n
I want to plot the 1st to 5th order filters. How do I input H(jw) into matlab? The tf(num, den) is not efficient in that...
"The simplest high pass filter is a capacitor in resistor in series, where the voltage across the capacitor is used as output." Quote wikipedia
The picture of this simple high pass filter is found at: http://upload.wikimedia.org/wikipedia/commons/f/fe/High_pass_filter.svg.
I wonna get some...
URGENT: Lyapunov Equation for backward continuous-time Kalman Filter
Hi,
Consider a continuous Kalman filter running backward in time as desired in a "two-filter" smoother. What would be the form of Lyapunov equation for this backward-time filter?
Given a system: dx/dt = Fx + Gv, and...
Homework Statement
A 1kHz square wave with an amplitude of 2V (peak to peak) is applied at the input V-in of the circuit shown. The resistor R1 = R2 = 10 kΩ, and C = 0.02 μF.
a) What is the effective time constant of this circuit?
b) What is the minimum and maximum voltage reached at...
Hi guys, what does it mean to observe a filter response to a unit step?
The book gives a transfer function and I've recreated it in Proteus ISIS. Now it asks me to simulate a square wave as an input (i used a pulse generator), and then observe a filter response to a unit step, describing the...
Hi guys :) I'm going through some prep. work for my modules in Fall and I've come across a question I'm having some difficulty with.
Homework Statement
The question has a transfer function for which I need to find the differential equation relating the output voltage and the input...
i have come across two different formulas for ripple factor:
One is r= (Vrpp/Vdc), where Vdc is the dc voltage of the output and Vrpp is the peak to peak ripple voltage. My professor uses this formula and I have also seen it being used in basic electronics by Floyd
Another one is r= Vrms/Vdc...
I am presently working with data fusion of redundant sensor data, basically trying to put together data from an IMU, a gyro and odometry...
My question is whether the accuracy of the final state be greater than the accuracy of the most accurate sensor used in the ekf?
Thanks in advance for...
If electric waveforms such as square waves, sawtooth waves, and triangle waves are really no more than sine waves with added harmonics, one could run such a wave through a bandpass filter (or several) and isolate one of the harmonics as a sine wave?
Homework Statement
Low-pass filter allows signals of low frequency to pass while attenuating high frequency signals; similarly, a high-pass filter allows signals of high frequency to pass while attenuating low frequency signals. The signals here can refer to voltage or current in the...
I am reading some noisy data from external sensors and trying to smooth it out. I know very little about discrete filters. When looking at my data in my plotting program (kst), I applied a low-pass filter and it looked great so I tried to implement a similar filter in my own software. In the...
There are 2 new models of water filters made by South Korean companies and this is what they claim:
The Wave-Q and Megafresh Filter, both of which are made in South Korea, use a device called a vortex pump to circulate the water in a container. The circulating water is then forced through a...
Please how do i transform this transfer function of a highpass filter
H(w) = jwR2 / [ (R1R2/L) + jw(R1 + R2)] to
H(w) = [R2/(R1+R2)][jw/(jw+wc)]
wc is the corner freq.
The circuit consists of a voltage source Vs(t) ,R1 in series with R2||L,Vo collected on R2.
Thanks.
Trying to understand how sallen key LPF works. But I can't figure out why there is a feedback path from op amp output to input thru a capacitor. Is it a bootstrap cap. What exactly is bootstrap?
Hello everyone, this is my first post, and I hope I have put this in the right area. I am looking to understand something about the behavior of a low pass filter. When an alternating current is passed through a low pass filter, the higher the frequency, the lower the voltage output of the...
Hello, I have taken the attached filter response graph of filter gain to frequency created in micro-Cap. My cutoff frequency is 1kHz.
How can I measure the roll off rate in db/Dec based on this graph ?
Perhaps there is a formula ?
Any help would be appreciated.
Hi
I have a general question: When I want to choose a low-pass filter, then what parameters of the signal determine what frequency it should have? I know my question is broad, but I would appreciate some pointers.
Niles.
I am having trouble seeing how a matched filter for FSK is any more "coherent" in its detection than an envelope detection incoherent FSK demodulator. The matched filter simply requires a precise sampling time at the output, however, surely so does the incoherent FSK demodulator?
Matched...
Hello,
I need some interpretation/analysis of the air HEPA filter results for my school project. I don't know exactly what are the standars of those elements(Al,Br etc.) so I can't say if they are below range or above range. Please, if someone can help me I'd be very grateful.
Here is the...
With bilinear transform (s=z-1/z+1) determine the differential equation for a 1st order discrete HP filter fith samplingfrequency f_s=150 Hz and lower cutoff frequency f_c=50 Hz. Also set the passpandgain to 1.
This is how i did:
Discrete variable: Ω=2π/3
Equivalent cuttof frequency...
I'm having a hard time visualizing what happens on the plates of the capacitor in series with a resistor in a high pass filter circuit. When the input to the capacitor is high, assuming a sine wave (say +5V) what happens on the opposite plate of the capacitor (Vout)? Should the output follow the...
Hi Everyone,
I read an article by Barry L. Dorr about how to implement a Low Pass Filter in software, however, the equation that he gave confused me as I didn't see any sort of convergence to the value desired.
So here is the equation:
y(n) = (1 - 2^(-k)) * y(n-1) + x(n)
x is the input, y...
Homework Statement
A high pass filter tuned for a corner freq. of 40 000 rad/sek and with a damping coeffisient of 1/sqrt(2) is being subjected to a square wave voltage with amplitide of 1 volt and 8000 rad/sek.
What is the amplitude of the fifth harmonic on the output side of the filter...
Homework Statement
See attached.
Can somebody explain how the resonant frequency w0=1/RC. I worked it out by setting imaginary Z(s)=0. The answer I get is j√2 which is obviously wrong. Is it wrong to calculate the resonant frequency in this manner in this case?
Homework Equations...
I built a clock generator using a 555 and I fed the output to a high pass filter. It works for the most part, BUT the input voltage ranges from 0 to 5V while the output is -5 to 0 V. I can't figure out why this is happening. I'm new to EE, so bear with me.
Consider the passive high-pass filter that consists of a resistor (R) and a capacitor (C). The frequency response is
H(\omega)=\frac{j\omega C R}{j\omega C R + 1}.
What would be the impulse response of this high pass filter? This question translates to how to evaluate the following Fourier...
Hello, I want to make B&W camera, for UV photography. I already destroyed two ccd's by trying to remove it. First stopped working after tiny golden wires were damaged. About second ccd I don't know. When I putted it into smartphone, in camera mode it showed black image. It seems that I didn't...
Homework Statement
I am supposed to find the circuit design for a first-order low-pass filter. The filter must be made of resistors and capacitors only (no inductances). Furthermore, the output voltage must be measured over a resistor or something in parallel with a resistor.
Homework...
Homework Statement
Hello!
Problem is as follows: during measurements laboratory we examined characteristics of a third octave and 10% filters, we were noting down two values at each step --> frequency (ranging from ~1000 to ~1600 Hz) and corresponding voltage. However, in order to read the...
I have a question regarding the relationship between differential pressure across a filter, the airflow through the filter and the size of the orifice that the aire is moving through. I would like to be able to predict differential pressure required to maintain a constant airflow as the filter I...
My professor in Feedback Control Systems told me that a lead-lag compensator is basically a low pass filter and that you can't amplify high frequencies because it requires a lot of energy. Thus, you can't design a PID/lead-lag compensated transfer function which acts like a bandpass filter. Is...
I was wondering how a bandstop filter works when it is connected in parallel as in the picture.
I know that the low pass filter eliminates higher frequencies and the high pass filter eliminates the lower frequencies. I understand how they form a bandpass filter when connected in series...
Homework Statement
Get the transfer function of a second order Chebyshev passband filter, with central frequency f0 = 1 [kHz], lower cutoff frequency fc=670 [Hz], 3dB ripple in the pass-band and 30dB of gain in the central frequency.
Homework Equations
Maximum allowed variation in...
Minimising a function related to a "Bloom Filter"
Homework Statement
I'm looking at a problem that requires me to find k that minimises the function f. Where n,m are to be treated as constants.
Although not needed for this problem the context is that the function f approximately describes the...
Hi all,
I have a standard local level model, but the disturbances are not independent:
y_t=μ_t+ε_t, μ_t+1=μ_t+η_t, E(ε_t η_t) =/= 0
In order to derive the Kalman filter, I rewrite this model in state space form
y_t=Z_t α_t+ε_t, ε_t~NID(0,H_t ),
α_(t+1)=T_t α_t+R_t η_t...
Homework Statement
Design this circuit to give a cut off (-3dB) frequency of 1kHz, a low frequency gain of 20, and an input impedance equal to 22kΩ
Homework Equations
The Attempt at a Solution
So, I started off with Vout/Vin = [-R2/R1]/[1 + sCR2. I also know that the dc gain...
I need your help in understanding the concept.
Actually, I am trying to understand the grounding concept here:
Attached is the snapshot:
Hi Folks,
I need your help in understanding the concept of how to measure the output voltage.
1. Initially, I tried to monitor the voltage...
Hello, I have been asked to:
- design an LPF with a cut off frequency of 17kHz and a roll-off of 40dB Decade. I have attached a picture of the circuit diagram I came up with.
Can someone please confirm if I have this correct ?
The second part of the question was:
- prove both time domain...
Hi,
I am currently learning and trying to build an extended kalman filter. However I am not sure how to created the measurement matrix. The measurement matrix H is described using formula 3.6 on page 18 of this document
http://www.scribd.com/doc/54702247/UAV-Design
My problem is that...
I'm trying to put some LED's on our racecar. They're 7 segment LED panels where each segment is 5 LED's with a 220 ohm resistor on the end.
The car runs on 12 volts with engine off and 14 with engine on.
I have power (Vin) coming off a distribution block, ground also goes to a...
.
My old car has a plastic fuel filter located between the fuel pump and the carburator fuel inlet.
Whatever the engine RPMs are, this filter is only about 40% filled, it is never replete.
This happens whatever the filter position is, vertical, horizontal, tilted...
Currently the filter is...
Homework Statement
We have a waveform with peak to peak amplitude 2V and a frequency of 600Hz. If this signal is to pass through a low-pass filter with a passband of 3.5kHz, explain why some distortion may occur to the waveform when shown on an oscilloscope.
The Attempt at a Solution...
Hello,
I am designing LC low pass filter for single phase sinusoidal pwm inverter, where the cut off frequency is f = 50 Hz.
And i have to chosse L, C such that: f = 1/2π√(LC)
but there is many combinations of L and c that result in this cut off frequency.
So my question is, how to choose...