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).
1. You have a series circuit consisting of a ac power supply, a 600 ohm resistor and a 73 nF capacitor.
If the circuit is configured as a low pass filter, what frequency will cause the gain to be 0.25?
2. If the circuit is configured as a high pass filter, what frequency will cause the gain...
Homework Statement
The input signal of a first-order lowpass filter with a transfer function given by eqn 1 below and a half power frequency of 200 Hz is eqn 2 below. Find an expression for V_outHomework Equations
eqn1:
H(f) = 1/(1+j*(f/f_B) where f is the frequency and f_B is the half-power...
What is the general Fourier Transform for a low *** filter if the lowpass filter also has a bandwidth of W Hz, and fc >>W,?
I think it would this:
∂(fc) + ∂(f-fc) + ∂(f-fc)
Homework Statement
See Explanation below for details of my confusion.
Homework Equations
The Attempt at a Solution
Hello all,
I've derived a transfer function, T(s) = \frac{\frac{-R_{2}}{R_{1}}}{1 + \frac{1}{sCR_{1}}}, but I can't seem to derive the corner frequency...
Homework Statement
Construct a low-pass filter and measure the gain (Vin/Vout) for a range of frequencies 20 Hz to 10 kHz using an oscilloscope. Plot your data along with the theoretical curve. Use a semi-log graph. What is the half power point for this filter? Does it match the theoretical...
Homework Statement
Consider a low-pass filter with RC=2x10-4 s.
a) Calculate the -3db frequency for the filter.
b) By what factor will the amplitude of a 10 kHz input sine wave be reduced by the filter?
c) By how many db will the power be reduced by the filter at 10 kHz...
Hi,
I am not sure if this is the right forum to post this. I am working on a Kalman Filter for battery state of discharge estimation during discharging process. I am using a Linearized Discrete Time Kalman Filter to estimate the State of Discharge/SOD (how much % of charge has been taken...
Hello...
Am undergraduate EE, and am working on my final year project which is the development of prosthetic arm which will work on signal from muscles taken from surface myoelectric sensors.
First of all i will explain about circuits i want to build, and i wish i will have comments...
If I have the unit impulse response function for a discrete-time LTI system (Unit sequence response?), h[n], how can I calculate the time taken for the output to fall below 1% of its initial value, after a unit impulse is applied to the input?
In particular, I have:
h[n]=(\alpha...
I'm conducting a heat transfer analysis on an instrument, but must first overcome my apparent lack of knowledge of optics.
Light is incident on a neutral density filter. The ND filter consists of 0.050" thick quartz with a a negligibly thin metal coating with emissivity of 0.065 on the...
Hi,
I am working on Pedestrian dead Reckoning using Particle filtering in matlab, I am using mobile accelrometer sensor to detect number of steps and stride length and calculating the total distance travelled. I want to use particle filter to enhance accuracy in my results. I have read the...
I trying to learn extended kalman filter. I am trying to simulate positions of point by angle mearsurments taken by an observer moving on a straight line. The EKF implementation does not converge. Below the MATLAB script
clear all; close all; clc;
%Generate staright line positions
T=300...
Homework Statement
I have a transfer function from a second order chebyshev filter and the general transfer function of a sallen-key circuit. I have some questions.Homework EquationsI am using a 2nd order low-pass filter sallen key on page 8 of this pdf...
Homework Statement
This is a twin-T notch filter.
[PLAIN]http://l23.sphotos.l3.fbcdn.net/hphotos-l3-snc4/hs1360.snc4/163224_10150132441064992_712009991_8008832_7339032_n.jpg Homework Equations
R = R
C = 1/sC
L = sL
The Attempt at a Solution
Not sure if my complex impedance equations are...
Homework Statement
We dropped coffee filters from 4.39 M recording the time it took for them to fall, and their masses as followed.
1 Filter- Mass= .86G, Time it took to hit the ground= 3.94s
2 Filters- Mass= 1.76g, Time it took to hit the ground= 3.25s
3 Filters- Mass= 2.72g, Time it took...
I'm trying to design a low pass filter from a transfer function (with one pole and one zero), and according to my textbook, the circuit which represents such a transfer function is of the following kind:
DC gain is 16.
Yet I get complete attenuation for low frequencies? Could my component...
Hello,
Please help me with the following problem.
Given a measured signal which has to be smoothed. A lowpass filter has to be applied. The signal is available as measured data (a data file on the hard disk, numerical, not real-time) ( it has to be applied in C or C++). The filter...
I'm working on a college project building analog guitar effects. I want to build an auto wah. It's essentially a variable resonant frequency band pass filter. Traditional auto wah's either use a low frequency oscillator for a constant 'sweep' across the filter's frequency band or use an envelop...
Hi,
I have a signal f(t) with nyquist rate W, i.e. the maximum frequency is W/2.
This signal is filtered with an integrator (simulated in Simulink) the following way:
f_I(t) = \int_t^{t+\frac{1}{W}} f(t)\,dt
In words: I integrate the signal for a period of 1/W, then the integrator is...
Hey guys, I have some problem understanding why an ideal low pass filter cannot be implemented in reality. I do not understand the reason given in wiki " because the sinc function's support region extends to all past and future times. The filter would therefore need to have infinite delay, or...
Hello,
Im working on estimation of inertial navigation system using kalman filtering.
Can anyone help me finding the state space model of inertial navigation system used to estimate the states via kalman filter.
An early response is needed.Thanks in advance.
Dear All,
I have an adaptive bandpass filter function, which has only one center frequency dependent co-efficient, w(n) to be updated. I would like to find the time function of the co-efficient,w(n).Can anyone help me?? Thanks
hi all,
m trying to implement sensor fusion of two three axis accelerometers data.can anyone help me in modelling this sensor and fusing for state estimation using EKF?
thanks in advance.!
Hey everyone I have recently started a circuits class, and am enjoying it. However, the high pass filters have slightly confusing me.
I recently set up a circuit that was straight from a wall socket meaning that it has a frequency of ~ 60 Hz. My high-pass filter should filter out all of the...
can anyone please explain me matched filter in detail ?
my understanding is as follows ( in case of a radar).
u transmit a signal and during reception have a filter in ur receiver which continously checks in the received echoes whether the echo has the same shape of the transmitted pulse.
is...
I am designing these brackets on a ventilation system to hold filters that my company stocks regularly. The vent is about 49.5"x49.5" and the filters are about 23.5"x23.5". Placing 4 filters in this square vent leaves about 1.25" on each side. I have designed the brackets so that they block the...
Hello,
I'm looking for a guide on the steps to design passive butterworth filters, specifically the steps on how to find the L and C passive elements using the butterworth polynomial, the cutoff frequency, and the terminating/load resistance. Is it necessary to use continued fractions? My...
I am trying to implement a kalman for use in sensor data fusion, for 3 axis accelerometers, 3 axis gyros, and 3 axis magnetometers for a helicopter UAV project.
The roll, pitch, and yaw need to be known. Gyros do a great job of doing this, but the problem is that they drift of the zero value...
I'm doing a question about a laser which emits blue and green light.
It asks about the light after it has passed through 'a green filter'. What passes through, green or blue light?
I originally thought green light must pass through, then realized it could mean green light is reflected.
Dear all,
I'm trying to implement an Extended Kalman Filter based SLAM for orientation and angular rates.
To ease up things I discarded the estimation of position and linear velocities. I'm using a quaternion based approach with translation vectors of 3D-points/landmarks as measurements...
Okay, I want to add a filter onto the end of this circuit with the transfer function:
\frac{1 - 3e^{-sT} + 3e^{-2sT} - e^{-3sT}}{s^{3}T^{3}}
(T is the sampling period)
I'm using PSPICE. The denominator seems simple enough to implement, just 3 op-amp integrators in series (right?), but...
Hey guys,
Basically, I have been doing some testing with regards to tactile vibrations (I know that isn't very electrical) and using a HET have developed several amplitude plots in the time domain. I've been sampling at 5000Hz and I want to remove the noise from my signals to leave me with a...
Homework Statement
Given: K=17, R1=R2=6,247 Ohm
Calculate the value of C1=C2=C to set the center frequency of the filter to 17.3 kHz.Homework Equations
w0 = 1/[C*sqr(Rth*KR2)] from lecture notes
R1=RthThe Attempt at a Solution
w0 = 1/[C*sqr(Rth*K*R2)]
C= 1/[w0*sqr(Rth*K*R2)]
C=...
Hi,
I'm currently implementing a visual 3D model-based vehicle tracking system as my undergrad dissertation. I've implemented the vehicle localization algorithm and now have an estimate of the x, y location on the ground plane as well as the orientation angle of the vehicle which would like...
Hi there, I am very new to optical domain, and I am only used to the common bandpass filter that we use on circuits, those RLC and OP-AMP based bandpass filter.
I went through few books and can't really find the difference, do anyone have any link regarding this issue or idea about this...
Homework Statement
Our job is to recreate the system in the above diagram in Matlab. I've been able to do all the stages effectively except the "matched filtering" part.
Homework Equations
The Attempt at a Solution
I don't really understand matched filtering very well. I...
For some experiments I need to be able to filter out blue light with either special light bulbs or a screen around the bulbs. It seems an orange coating on the bulb or an orange screen around the bulbs will do the trick, but I need to filter out as much blue light as possible. Something like 99%...
Hi,
I need to filter my data using a low pass filter. I would like to do this using Matlab. The sampling rate of my data is 200 Hz, and I would like a cut-off frequency of 30Hz. Someone can help me, please?
jo
Homework Statement
I need to find the DC and high frequency (HF) gain of this filter:
http://www.flickr.com/photos/96575810@N00/4420162040/
(The url is [PLAIN][PLAIN]http://www.flickr.com/photos/96575810@N00/4420162040/ in case that doesn't work)
Homework Equations
The book defines...
Hi there.
Sorry for my poor English first.
I have been reading chapter about polarization in Feynman Lectures on Physics.
There is a experiment about polarization using 2 polaroids and birefringence cellophane located between two polaroids.
optic axis of two polaroids are 0 and 90 in...
First post here. Found this place while looking for a solution to my problem. My background is Navy trained electronic tech. (FC to be precise) So an engineer I'm not, but I do fix the stuff.
Anyway, at work, I have a 3 phase full wave rectifier with a capacitor ripple filter. Here's a...
Homework Statement
I am doing a project on mathematical analysis of image restoration techniques, using linear restoration filters such as
1.inverse filter
2.pseudo inverse filter
3.weiner filter and
4.constrained least square filter
Homework Equations
The Attempt at a...
I'm trying to understand the Wiener Filter, and I have a few questions.
1. How can there be such a thing as a correlation matrix of 1 vector. I read here:
R_yy = E[ y(k) * y^T(k) ]
where y(k) is a vector, and y_T(x) is the same vector transposed. I thought correlation represents the...
Anyone who can tell me the corelation between Hartridge Smoke Unit (HSU) and FILTER SMOKE NUMBER(FSN) as I have the two systems giving one in HSU and the other in FSN.I would like to compare the result given by the two SYSTEM
I've got this homework problem in a circuits class and I think I understand it but once I get a good ways into it, I kind of run into a dead end. It's kind of hard to explain, so I will just show the problem and my steps toward solving it. Hopefully someone here can point out the flaws in my way...
I'm looking at a guide by Texas Instruments on active filter design. In it are the following equations for a second order lowpass filter, verbatim:
The coefficient form of the denominator: s^2 + a_1s + a_0
Normalized: P(s) = (\frac{s}{\sqrt{a_0}*\omega_c})^2 + \frac{a_1s}{a_0*\omega_c} + 1...
A question regarding power supply efficiency: The theoretical maximum efficiency of a full-wave rectifier circuit with a resistive load and no smoothing is around 82%. In the calculations to derive that the resistance of the source or the rectifiers does not enter into the equation, so the...
I have been reviewing Sakurai's treatment of the SG experiment by analogy with polarized light, and I realized that I am not sure that I really understand how to construct in a laboratory the SG_{y} filter to produce and separate the \left|S_{y};\pm\right\rangle states that are analogous to...
I'm to design a 2nd order, N=2, butterworth HPF starting from the normalized transfer function for a LPF:
HN(s)=1/(s^2+1.414*s+1)
Given:
T=0.004
Ωc=0.8 pi
wc=192 pi
To find the transfer function of the HPF, substitute s for wc/s:
H(s)=HN(wc/s)=s^2/(s^2+853*s+363833)
Here's my...