Questions tagged [filter]
A filter selectively processes input signals in frequency- or time-domain.
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Integrators and the mechanics of a state-variable filter
I'm trying to understand how this topology of state-variable filter with summing amplifier produces a band-pass filter at the second integrator's output, in the context a parametric audio equalizer. ...
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Issue with 3rd order Butterworth low pass filter simulation
I wrote up some code in MATLAB that's supposed to simulate the frequency response of a third order passive low pass Butterworth filter with a cutoff at 10kHz. The curve seems to match the results I ...
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Reason to increase output impedance in a non-inverting op-amp
In the schematic above a non-inverting op-amp filter is shown.
Why is R2 added within the feedback loop? Does it serve any purpose?
Outside the feedback path (right before C2) it could serve as a ...
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Passive filter design
I'm working on a project requiring a passive filter to block signals below 10 kHz and allow those above 10 kHz, but at 10 kHz, I want to partly pass the signal, say half of the signal. Seeking advice ...
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Why would a low-pass filter be connected to +5V on an RS422 differential line?
I am interested in a datasheet's schematic for my own PCB design of a similar system.
In my system, I am receiving an RS-422 differential line, and would simply be tempted to put a 100 Ohm terminating ...
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Trouble with filter using Laplace transfer function in LTSpice
I would like to introduce an ideal 5th-order Bessel filter to my simulation. My initial thought is to use a voltage-dependent voltage source and Laplace transform. I copied the Bessel filter ...
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Find resistors for an inverting op amp band pass filter
I'm trying to save a problem that shows the following band pass filter:
Note: the op amp doesn't need to be a TL081, it's an abstract, ideal op amp.
I need to find resistors \$R1\$ and \$R2\$ so that ...
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How do you chain 2-port S-parameters onto a 1-port S-parameter?
With 2-port S-parameters, you can build up a circuit by chaining them together using ABCD or T-parameters, simply multiply the matrices:
We have measured a complex single port S-parameter of an ...
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Do I need to add a filter for an isolated DC-DC converter?
I have purchased three CUI Isolated DC-DC Converters, the models are VHK50W-Q24-S5, VHK150W-Q24-S12 and VFK600-D24-S24. I wonder you could help / guide me to the correct use of them.
Questions:
I saw ...
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How can I calculate the parameters of an inverse Chebyshev active filter?
I'm currently designing an inverse Chebyshev 7th order low-pass filter with three 2nd-order low-pass notches and an RC low-pass filter.
I've already used Simulink to obtain the s-domain transfer ...
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strange phase behavior RC low pass filter
I have a low pass RC filter (R=12Ohm, C = 22µF) Which is showing some strange behavior in the phase shift. The cutoff frequency is around 600Hz, as calculated.
But the phase shift goes to -45° only at ...
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Non-standard low-pass filter design
While experimenting with various low-pass filter topologies (audio application), I came up with the following design:
simulate this circuit – Schematic created using CircuitLab
It seems to ...
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How to filter a noisy PWM signal without affecting rise and fall times
I need to read the frequency and duty cycle of a PWM signal that is expected at 88Hz. It is getting a lot of noise (during radiated immunity).
Before noise:
After noise injected:
What filter would ...
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Bandpass Amplifier
This is my frequency response , the point is if i change the capacitor values C1 and C4 my signal distorts on the second lobe in time domain and gain curve is not flat in the range. MY bandwidth is in ...
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Discrepancy Between Bode Plot Predictions and FFT Output for Higher-Order Low Pass Filters on a 10 kHz Square Wave
I have conducted an experiment where a 10 kHz square wave is input through low pass filters of 1st, 2nd, 3rd, and 4th orders. After passing the square wave through these filters, I observed the FFT (...
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Transistor specs in the capacitance multiplier
I'm working on a constant current power supply and as a first step designed the following rectifier with a filter. I know the bottom rectifier is inactive, but with couple of switches the circuit ...
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Input Filter for Current Sense Amplifier - ODrive
Out of curiosity, can anyone explain to me why the input filters for the current sense amplifiers in the old ODrive schematics are unbalanced (i.e., the external resistor is only on the negative CSA ...
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Incorrect cutoff frequency using two Sallen-Key filters to build a bandstop filter
I'm currently having trouble troubleshooting my answer. I have to make a bandstop filter that has a cutoff frequency of 100 rad/s, and 10^6 rad/s using two Sallen-Key filters. I made the low and high ...
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Differential DAC filter capacitor options
The standard output filter for a DAC with a differential voltage output looks this way:
simulate this circuit – Schematic created using CircuitLab
However, some DACs have this filter ...
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RC-filter transfer function confusion
simulate this circuit – Schematic created using CircuitLab
I have a question about the transfer function of the above RC-lowpass filter. If I switch places of the capacitor and the resistor to ...
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Switch Mode Power Supply / GPS - Filtering+Shielding
I'm working on my first RF PCB, for GPS/ GNSS and am particularly concerned about Noise/ Interference. Hopefully someone can shed some light, or point me toward a similar thread?
It's worth noting ...
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STM32F0 VDD / VDDA connected
I want to use an STM32F0x to interface a i2c sensor via USB. Reading the sensor is triggered by an interrupt.
If I don't do any ADC I should be fine with connecting VDD and VDDA right?
I know this ...
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AC power line filter no load current consumption
Our device is an induction cooktop rated for 2 kW of power. We have added an AC line filter in series with the AC supply line for EMI/EMC performance. Following is the circuit which we have ...
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Why is Voltage Drop Across the Inductors of an LLCL Filter a Concern for Grid-Tied Inverters?
I'm working with a single-phase grid-tied inverter that utilizes an LLCL filter to interface with the grid. I've come across design constraints that mention maintaining the voltage drop across the ...
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Trouble understanding resulting bode plot while getting hands on filter design
Recently tried to get hands on filter design, I tried to design à simple low-pass RC filter as shown here.
simulate this circuit – Schematic created using CircuitLab
Cutoff frequency must be \$\...
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2nd Order Butterworth filter design. How to find "m" and "n" values
I was reading this article Active-Low Passfilter design from Texas Instruments, and I've been racking my brain all day trying to find how they determine the values for "m" and "n" ...
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How are RF filters constructed?
I want to know what filter circuits look like in the RF (MHz-GHz) frequency range. Are they just like low frequency LC filters, but with appropriately adjusted component values?
For example the VLF-80+...
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230 VAC 16 A relay Circuit for Reduced EMI
I am designing a PCB that will needs EMI testing from a laboratory. I have a 230 VAC 16 A relay in PCB. I am not sure will it cause EMI issues while switching between loads or not. If anyone as better ...
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Problems with output signal of a 2nd order low pass Sallen Key filter for an electret microphone
I'm having problems with a small circuit based on the amplification of a audio signal received by an electret microphone. It goes to a 2nd order Sallen Key low pass filter circuit with an ...
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In Bode plots what does phase tell us for passive filters (open loop)?
I was just playing around with a passive filter to erase some noise - one that should work between 80MHz and 1GHz.
I'm aware that the phase in Bode plots gives data about the time delay between the ...
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How to eliminate the VFD noise affecting digital sensor reading?
I have a problem getting correct readings from a 5v digital sensor connected to an Arduino Uno board. I get correct reading until I start the VFD that drives a 3-phase motor.
The sensor reading then ...
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Smooth a PWM to DC stable [closed]
I have to smooth a PWM (0V- 12V, 200Hz) who trigger my pic12f1572 via transistor 2N3904. What is the best way?
I have PWM source connected to 2N3904 and output from 2N3904 is connected to PIC uc. I ...
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General formula for the ripple voltage in a loaded bridge rectifier
What is the general formula to calculate the peak to peak ripple voltage and Vdc average of the voltage at the input of the 7805 voltage regulator in a circuit like this?
Suppose the load is a fixed ...
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Input capacitors to the 7805 voltage regulator [duplicate]
What is the purpose of the 1000 µF and 0.22 µF capacitors at the input of 7805 voltage regulator?
Input to these capacitors is the rectified pulsating DC voltage. What will be the shape of this ...
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Input and output voltage of 7805
In the diagram below the input voltage to the ic 7805 is the output voltage of the capacitors (1000 micro Farad and 0.22 micro Farad).
The peak voltage arcoss the input of ic 7805 is the same as the ...
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lowpass prototype to bandpass filter
Bandpass filter with a center frequency of 10 rad/sec and bandwidth of 20 rad/sec here, wo= is mentioned as geometric frequency that's why I am confused.
The solution in which picture is correct?
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How to find transfer function for this pi-filter using FACTS Method with 6 reactive elements?
Am trying to apply the FACTS method to find out the transfer function for this circuit as shown below. This is a Pi-filter circuit with all its component parasitics and also including the source and ...
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Digital Low Pass Filter and PWM Signal
I have a PWM signal going into an ADC.
After the ADC the signal is being filtered using an IIR single pole filter.
Performance is exactly what I want with one exception. The purpose of the filter is ...
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Interdigital filter ground connection on PCB
I have used an online designer utility for my 5 GHz to 6 GHz RF output filter, on the schematic it generated it had shown ground attach points, but I am not sure if I designed ground connections and ...
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Synchronising data input and filter coefficient so that both reach at same time and give filter output in semi parallel/parallel filter in Verilog
I have designed an 8-tap filter using 8 coefficients in a semi-parallel fashion. I want to get the correct output for a FIR filter design by using 8 DSPs and one SRLC32E register. Here I pass my input ...
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Second Order Low Pass Filter, replacing inductor with VCCS and Capacitor
My instructor told us that we can replace an inductor in the following way.
Now, I want to construct a second order low pass filter using Voltage Controlled Current Source, Capacitor, Resistor of ...
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What is the formula for ripple factor of the filters?
In some books I find the formula for the ripple factors of filters (like LC and RC) to whome rectifier are connected at input as
Ripple factor = Vr.m.s/Vdc
While in other books
Ripple factor = Peak to ...
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Rectifier output voltage in RC and LC choke input filters
Why does the choke input filter produce a DC output voltage equal to the average value of the rectified voltage given as input to this filter, while the capacitor input filter produces a DC output ...
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Placement of filter capacitors in a circuit with multiple audio outputs
I have a multiple output stage of an audio circuit as in the picture attached.
I want to add a capacitor to eventually filter any DC at the output, therefore I placed a RC filter 10uF/100k(0,16 HZ) ...
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Methods for improving/smoothing the load cell signal
I am using a Delta AS02LC-A cell module and a Zemic 25 kg load cell. Here are some details of the load cell calibration certificate:
And this is the appearance, specifications and wiring diagram of ...
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Differential Mode EMI Filter Design for DC Power Input Noises
https://www.murata.com/en-us/products/productdata/8796777775134/ENFH0008.pdf
https://www.digikey.com/en/products/detail/murata-electronics/BNX022-01L/1825573
Hi everyone, I try to understand this ...
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Can the differential output signal of a DAC be AC coupled directly to the differential input pins of a class D audio amplifier?
The datasheet of the audio codec I'm using (CS4272-CZZ) suggest a filter on the differential output pins. Their suggested configuration also combines the signals into a single ended output. I want to ...
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Introducing RC Filter to reduce noise
I have designed a constant current circuit using an opamp.
If I want to implement an RC filter to reduce the noise, where can I add?
Option1: I am planning to add between the inverting terminal and ...
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Fine-Tuning a Circuit After changing VCA (SSM2641 to SSI2164)
A friend's accident led to a fried SSM2641 VCA in an Eurorack audio module. Determined to give it a new lease on life, I'm diving in, though VCAs are not my forte.
After searching for hours, it seems ...
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Input filter LC for switching power supplies
I have the following LC low-pass filter for a power supply.
I want the filter to cut-off unwanted noise caused by a DC motor.
simulate this circuit – Schematic created using CircuitLab
How can ...
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