Questions tagged [cutoff-frequency]

A cutoff frequency is a frequency boundary in a system's frequency response at which the power level is greater or less than a given fixed value.

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Waveform acquired from scope, what is the sample rate for post processing?

I want to make a noise measurement with my scope, but I need it to be band-limited. I am using a Tektronix TBS1102, which allows me to save to a USB flash drive an Excel/CSV file with the X and Y ...
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Input signal bandwidth of ADC

I prepare to use adc to do sub-sampling. Most SAR adc has -3dB input signal bandwidth in datasheet but no for delta-signam adc. Can I use modulation frequency as the bandwidth or there is another way ...
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Parallel-series RC circuit

I wanted to calculate frequencies of filter The module of impedance which I got is equal What is the frequency cutoff of this circuit? I've made a simulation but I wanted to get frequency cutoff.
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Why is the relation between voltage ratio and frequency a linear one in a lumped transition line?

In an experiment the cutoff frequency of a lumped transmission line is determined by measuring the ratio of the output/input voltages. The lumped transmission line is a ladder network of 40 capacitors ...
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Simulating an RLC bandpass filter with LTspice

I have analyzed the filter in question both in practice and in simulation (with LTspice) The calculations I performed to determine the high and low cutoff frequency and the resonance frequency are as ...
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Frequency response of low pass filter

I have an ideal low pass filter having cutoff frequency 1kHz. If I provide an input having single frequency component at 1kHz, will there be any output or zero?
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Filter for AC line coupling with audio signal source

I need a sharp notch filter (higher order) for the 50-60 Hz band, to be placed between AC 220/125 V power line and an audio source (not necessarily amplified), such that the input signal from the ...
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The field in a waveguide at exactly the cut-off frequency

Can anyone explain to me qualitatively, what kind of field exists inside a waveguide at EXACTLY the cut-off frequency? I would be grateful if an explanation was given about waveguides with metalic ...
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I want to find the corner frequency of this second order low pass filter

As there is an isolator an between, I have tried multiplying the individual transfer functions to get the combined function and then equated it with -3dB.
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Can an ADXL327 accelerometer be used with theoretically unlimited bandwidth?

I saw several studies that use the 3-axis ADXL327 accelerometer, 0.1-3000 Hz band-pass filtered and sampled at 20KHz based on previous studies that showed that the signals of interest have frequencies ...
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Why is the noise gain these opamps 500? I feel it should be 250

I wanted to check the bandwidth of the first stage of an instrumentation amplifier configuration and this is the circuit: Since, the noise gain of an opamp is (1+Rf/R1), for each of the op-amps the ...
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Cut Off Frequency in the Frequency Response of RC circuit

In the frequency response curve of RC circuit, why does the curve falls rapidly after the breakpoint? It approximates to a certain amplitude upto the breakpoint. In the diagram, given below, it is ...
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Cutoff frequency of RLC band pass and band stop filter

I have found in a website that the cutoff frequencies of a series RLC bandpass and bandstop filters are: $$ f_c = \sqrt{\left(\frac{R}{2L}\right)^2+\frac{1}{LC}}\pm\frac{R}{2L}. $$ This is the link ...
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About the cut off frequency

I am doing a work that basically we need to study the graphs given by an oscilloscope, and with it, find the cut off frequency of the circuit that better approach the data given by the oscilloscope (...
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Frequency response of difference amplifier

I'm studying the difference amplifier circuit configuration of op amps, reading from this datasheet. I know that unlike the instrumentation amplifiers, the difference amplifier differential gain can ...
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Calculating the cut-off frequency

I have an inverter opamp with the next data : \$A=-25\$ \$A_{ol}=20\frac{mV}{V}\$ Unity Gain Bandwith\$=10^{6}\$ Then asks for the cutt off frequency, so the open loop its passed to db \$20\,\frac{V}...
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How can I find the cutoff-frequency in real experiment?

My Problem is that I can't figure out how to answer this question: The component values in the previous measurements have been known and the cut-off frequency could be calculated. In real life, this ...
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Signal is always attenuated by passive bandpass filter

I'm trying to build a passive bandpass filter with the cutoff frequencies of 0.001 Hz and 10 Hz. It seems that my signal is always attenuated. Why?
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Active low pass filter with cut-off frequency ~4250 Hz lets a 20 kHz signal through

I needed an active low pass filter for my project that can produce an output voltage within the required settling time and ripple voltage ranges. Although I managed to get a good enough output voltage ...
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Do we always take the corner frequency of a filter at exactly -3dB?

I'm doing some work on filters, but all the references I can find use a 'perfect' gain characteristic, with the trace starting at 0dB. Is the measurement for corner/cutoff frequency always taken at ...
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Manually calculated -3dB cut off frequency differs from the simulated value

I have been trying to do experiments with a differential BJT pair. As the output resistance for the common emitter configuration is R_c (1k), instead of finding the capacitance, I attached a 1pF ...
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Capacitive voltage divider frequency response and cut-off frequency

I'm working on designing a guitar pedal based on the topology of an old tube amplifier I own. Between the amplification stages I found an inter-stage filter that I cannot understand in the frequency ...
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Finding the cut-off frequency of a filter

For a general filter, what is the way to find the cut-off frequency? In this link Okawa Electronic Design shows a formula for the cut-off frequency of a Sallen-key filter that looks like: $$\text{f}_\...
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Cut off frequency in simulation does not match in calculation

I am an engineering student currently learning how to design low-pass active filters. Currently, I am having trouble matching my calculations with the simulation values. My design has the following ...
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Second Order Butterworth LPF Cut-off frequency determining from graph

I am trying to design a butterworth low pass filter with corner frequency at 2khz as seen below. And my problem is when I find its transfer function It is as follows: \$H(s)=\dfrac{1}{1+1.414\times (\...
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Bandwidth of low pass filter: measured with the cut-off frequency?

I have the following Sallen & Key lowpass filter: $$T(s)=\frac{\frac{1}{R_1R_2C_1C_2}}{s^2+(\frac{1}{C_1R_1}+\frac{1}{C_1R_2})s+\frac{1}{R_1R_2C_1C_2}}$$ The parameters values are \$R_1=10 k\...
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Setting the cutoff frequency of an active bandpass filter (op amp) and finding the phase in LTSpice

I am doing an exercise and my op amp cutoff frequencies are: lower 1kHz, upper 10kHz. I have found the phase shift of the filter, but since the graph I get does not make much sense for me I think it ...
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Cut-off frequency of a LED

I'm trying to solve this problem: A GaAs LED is at \$ 300 K \$ when the current density is 1000 \$A/cm^2\$ . The width of the active region is \$ 1 µm \$. Assume that, for that current, we are in the ...
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Sallen-Key Low Pass filter

I was trying to do a project on LT spice for the frequency response for Sallen-Key low Pass filter. But when I tried the Following circuit, I am getting a roll off 20db / decade instead of 40db/decade....
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Finding upper cutoff and lower cutoff frequencies on notch circuit

I need to find upper cutoff (UCF) and lower cutoff (LCF) frequencies based on formulas of a notch circuit, but I'm getting a quadratic equation (as expected) with an imaginary number (IN; not expected....
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Can I change a frequency band of an EQ board?

Is it possible to change one of the frequency bands of this EQ board? In particular, the low frequency adjuster is 100Hz and I want to make it 60ish Hz. My understanding is that i need to meddle with ...
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What is the formula for cutoff frequency for LCL filter?

I have an assignment for school and one of the questions is asking me to find the "bandwidth" of a "pi filter." This teacher miss words things sometimes and I know it's actually a ...
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Why won't the bandstop filter work in this circuit?

This is the EMG circuit I designed. The cut off frequency of the bandpass is 20-3k Hz. This somehow worked already. But the bandstop filter doesn't show. Why is this? This is the freq-vout graph and ...
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Is this design of a charge amplifier for a piezoelectric sensor correct?

This is the specifications that must be met: "Design a charge amplifier for a piezoelectric sensor that has 500 pF capacitance. It should pass frequencies from 0.05 to 100 Hz so that it can ...
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Did I interpret these multisim results correctly?

From the circuit above, this is what I have to do: " Connect the circuit with R3 equal to 470 kΩ. Set the input frequency to 100 Hz. Adjust the signal level to get an output of 5 Vp-p. Record ...
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How to compute for the capacitor to achieve a certain cut-off frequency?

This is my task : "Select new values for C1 and C3 to get a lower cutoff frequency in the circuit shown above that is less than 20 Hz." What I did first was choose 15Hz and then computed for ...
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I need help deriving the cutoff frequency of a negative feedback amplifier

I have the question and answer below for deriving the closed-loop cutoff frequency of a feedback amplifier circuit. I can follow the working out all the way until the last 2 lines, where the writer ...
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Gain error calculation for op-amp circuit in inverting configuration

For an inverting op-amp, calculate minimum gain that is required for the op-amp to achieve a gain error of 1%, if the required closed-loop DC gain is -9. If the input resistance R1 is 1Kohm,find the ...
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Summing Integrator cut off

I would like to know how to calculate cut off frequency of this summing integrator circuit. I fail to find anywhere on the internet how to calculate cut off frequency in this configuration. Then how ...
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2 answers
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My simulated coax cut off frequency is way far off the calculated value

I used the lumped model to model a coax cable as a low pass filter in MATLAB. I also included ESR which is supposed to resemble the dielectric losses. I derived my transfer function from the circuit ...
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How to get lower cutoff frequency?

These are the equations for finding lower cutoff frequencies for a BJT common emitter amplifier: In finding the cutoff frequency, capacitor impedance must match the resistance so that output voltage ...
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Higher cutoff frequency of op-amp circuit is different in simulation and on paper

I have the circuit below: This is an inverting amplifier, the op-amp that is used is 741 as shown in the circuit. Open-loop gain of the op-amp is \$ A_{0}=2\times 10^5 \$ and the cutoff frequency of ...
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Cascade amplifiers with different corner frequency

In these 2 cases I have the output of a non inversor circuit connected to the input of an inversor circuit. The only difference is the resistors. What I have noticed is that the cutoff frequency is ...
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How to find the cutoff frequency using Simulink (from the scope)?

R=1000 ohm C=0.1uF I need to find the cutoff frequency from the scope and to show it matches the theory \$f= \frac{1}{2pi*RC}\$ In this case it's 1591Hz. How do I measure it?
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Frequency dependent behavior of an inverting configuration of an opamp

I am a third-year chemistry student. I have essentially the understanding of a second-semester physics student when it comes to circuitry and electrical engineering. For reference, I know what gain is ...
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How to find the cutoff frequency of an underdamped second order low pass filter?

I've learned that for a first order low pass filter (LPF) the 3 dB frequency is one where the amp's gain is (surprise) -3 dB below the DC gain. However, on a second order LPF that is underdamped we ...
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Finding transfer function and tuning cutoff frequency of High-Pass FIlter

I have a schematic for a High-Pass filter that has a cut-off of around 7Hz. I obtained the designed online and want to tune it to have a cutoff of 5Hz instead. I assumed I would proceed in the ...
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4 votes
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High pass filter - Cut-off frequency calculation doesn't match simulation

I have made the following simulation with the circuit you can see below: I'm asked to find the cut-off frequency for this filter. From the simulation, it looks like it \$f_c = 500 \text{Hz}\$ or ...
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Open-source DIY audio spectrum analyser and/or graphic equaliser

does anyone know of any OpenSource/DIY audio spectrum analyser projects can they direct me to an article, video, pics hackaday and instructionals style also I.C's old or new that i could/should try ...
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In an inverting amplifier configuration why does do the gain resistors affect the circuit's frequency response if their ratio stays consistent?

I've been learning more about the characteristics of op amps and I found in a non-inverting amplifier simulation that the gain of an inverting op amp falls off as frequency increases. This behavior is ...
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