Questions tagged [filtering]

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Dual brushed motors digital controller works on only one side

I'm actually developing a way to control, digitally, the speed of brushed motors with a Raspberry Pi. To do so, I use the following diagram where: The raspberry controls the shift registers (purple) ...
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  • 63
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0 answers
38 views

Instrumentation box, digital input signal conditioning [duplicate]

I'm designing an instrumentation box with opto-coupled digital inputs (BNC). For better noise/ground loops immunity/signal reflections I added 50 ohm resistors and 1n filtering capacitor (if needed). ...
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  • 51
2 votes
2 answers
61 views

Custom LED light bulb protection /

I wanted to design a custom LED light bulb, so I bought a couple and tore them down in the hope to reverse engineer them. Most of them implement a circuit with a chip shown as below, with the circuit ...
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  • 71
20 votes
8 answers
4k views

"Rounding" a square wave's corners?

I'm trying to create a keying envelope for sending morse code without nasty clicking and the consequential excess bandwidth. My current plan is to take the switching (essentially a square, but not-...
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0 votes
1 answer
61 views

How do you interpret LTSpice graphs?

I've created a circuit in LTSpice to model a fan assembly I'm looking to build. In the below circuit the current sources represent the fan and the voltage sources represent the voltage source I'll be ...
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0 votes
1 answer
88 views

Car power supply filtering circuit check

Could someone give me some advice if the power supply filtering on my automotive project is OK? The project will be running in a 12 V car, and pull around 4 to 5 A max. I have use a PMOSFET for ...
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1 vote
3 answers
213 views

Improved method of instrumentation amplifier input noise and RFI filtering

The following circuit diagrams are taken out of Niel Albaugh's The Instrumentation Amplifier Handbook I understand how the RC (tolerances) mismatches in Figure 4-16 (left circuit) cause the two time ...
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  • 1,310
18 votes
6 answers
4k views

What does this transistor circuit do?

I found a schematic which had this bit of circuitry between the +9 V (which apparently the author assumed to be > 9 V, more like 10-11 V) barrel connector and the +9 V supply rail. I tried to ...
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  • 429
1 vote
0 answers
16 views

EKF Design And System Augmentation Bearings Only Tracking

I am hoping someone can help me with some guidance or knowledge on the matter. Basically im setting up a "Bearings Only Tracking" simulation using the EKF/UKF toolbox within Matlab. I have a ...
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0 answers
52 views

Electro magnetic interferences (EMI) generated by power circuit reset low voltage integrated circuits (ICs)

The main question here is (explanation will follow): Is there a way to filter out low voltage oscillations (>10MHz) on pins that have to stay high for the system to function? Oscillations are ...
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  • 11
2 votes
2 answers
159 views

Question about Third order Butterworth Filter Design

I'm new to PSpice and filter design and I'm trying to design a third order Low pass Butterworth Filter with cut-off frequency = 10 Hz. Here is the circuit that I've designed: I've applied a 5V ...
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1 vote
1 answer
159 views

Is it easy to siphon power from a powered antenna?

I have a property which is in a bit of a hole. My driveway goes up to an elevation above my house where semi-local TV signals are present. When they were still in local business, I bought a powered ...
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1 vote
3 answers
2k views

Differential filters: high pass, low pass, band pass

I am looking to use a band pass filter in an EMG circuit design using the differential signals you receive from an op amp (differential/instrumentation). I have been looking for what is the proper way ...
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  • 326
0 votes
2 answers
955 views

Matlab code to determine and plot impulse response

I have a signal y[n], represented by the vector y in this form y[n] =x[n] + ax[n−N] About this signal: x[n] is the uncorrupted speech signal which has been delayed by N samples and added back in ...
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  • 115
0 votes
3 answers
171 views

Shifting level voltage of a signal

I have a signal, which can vary from 400 to 7000 Hz approximately. It is a kind of pwm signal and has the time of high level, Ton, 30 times longer than the time of low level, Toff. The shape of the ...
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  • 847
1 vote
2 answers
140 views

Automotive tachometer signal interpretation

I'm trying to build a custom dashboard for a car (Daewoo Lanos 1998 with Delco ECU). Tachometer signal, that comes to dashboard with a separate wire looks a bit strange to me. It seems that the signal ...
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  • 21
0 votes
1 answer
53 views

Inducing noise for testing AC line filters

From a previous post of mine, you can see that I am trying to test the efficacy of some AC line filters. I got it to connect properly this time without frying my load, but we cannot seem to replicate ...
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1 vote
0 answers
417 views

EMI filtering on multi-FFC assembly

an aspiring electronics engineer here. I do some electronics design for work and I'd like to know the following: If I have an assembly of a main board, to which an FFC cable connects into a second ...
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1 vote
1 answer
72 views

Is a higher capacitance rating ok for filtering?

I am newer to electronic design and bought the mpu6050 sensor chip, which the documentation can be found here: https://datasheet.lcsc.com/szlcsc/TDK-InvenSense-MPU-6050_C24112.pdf It says that pin 20 ...
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1 vote
1 answer
635 views

Ferrite bead pi-filter vs feed through capacitors in supply decoupling

How do I choose a feed through (feedthrough/feed-through?) capacitor to replace a ferrite bead pi-filter circuit? Manufacturers quote capacitance figures but what value should I choose this to be? ...
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0 votes
1 answer
150 views

Funtional role of op amps in a ADC filter circuit

I am a student trying to reverse engineer a rather interesting PCB, trying to learn from it but have come across some circuits that I am struggling to identify the roles of. This is the first part. ...
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1 vote
1 answer
309 views

Twin notch filter working

Can someone please explain to me in depth as to how this twin notch circuit is working. Also is what is the formula for finding the notch frequency because some sites give the answer as (1/2×pi×RC) ...
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0 votes
2 answers
227 views

Isolating A Noisy Component In A Circuit

I've been working on a project the past couple months or so and I am incorporating an lcd touch screen as an interface for it. The device is a small digital synthesizer. The problem I am having is ...
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-1 votes
1 answer
75 views

Would an 8 order analog filter be enough for creating a bandpass filter of 8-40 hz?

I am creating a project in which I need to an analog active bandpass filter. The opamps used in the active filters do need any feedback hence are more like comparators. There is a power line noise of ...
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4 votes
1 answer
428 views

Audio filtering circuit with capacitor shorted

I was looking at the Adafruit FONA cellular network modem breakout board schematic and found something that I can't quite understand. The breakout board has an audio input and output that both goes ...
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1 vote
1 answer
95 views

Conversion of a signal to digital pulses

The following signal is presented to me, and will vary in freq, but not amplitude from 10Hz up to around 25 KHz. Any ideas for a simple circuit that will convert this into a clean 3V3 square wave for ...
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0 votes
1 answer
272 views

Filtering of a 5 V square wave

We are building a system that interfaces an approx 3-20 KHz square wave that comes from an engines crank position sensor. It is an open collector sensor, so we have a 1 KOhm pullup in our system to ...
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0 votes
2 answers
76 views

Determining equivalent resistance to find the cutoff frequency

I am designing a low noise circuit for a precision application and require a stable voltage supplied to the circuit. I have determined that the MAX6250 voltage reference best suits my circuit. A ...
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2 votes
2 answers
285 views

How ac coupling in scopes does not give you a phase shift? Or does it?

For what i know, filtering something always gives some amount of phase shift. So how do oscilloscopes with ac coupling don't have that? Do they correct in software? If so, how they used to do it at ...
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1 vote
1 answer
237 views

Step Down Switching Regulator irregularity with ripple on output

Using the L5973D- I have followed the Schematic as the datasheet instructs, but I have tried two different inductors. I have found problems with other systems on the board with the one inductor (744 ...
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  • 373
0 votes
1 answer
184 views

Filtering current spikes in photodiode transistor selector

I am building a circuit for sensing photocurrent from a photodiode. The diodes are manufactured with selection transistors to form an active matrix and below is a model of a single pixel consisting of ...
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0 votes
1 answer
606 views

12V Jacob's Ladder circuit introducing noise on input and messing with PSU

I have made a Jacob's Ladder display for fun. I have no oscilloscope to give exact details, but there must be some kind of noise or high-voltage ripple that is resetting the display of my Lab Power ...
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0 votes
1 answer
84 views

Continuous Filter design for measure signals from Boost Converter out

So, I found a simulation that uses PID to control the voltage of a DC bus, for voltage measure the author use a "func transfer" in simulink. I wish to know what kind of filter he design and how can I ...
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  • 157
2 votes
1 answer
1k views

Usage Of Static Electricity To Remove Dust?

If I have a fine metal mesh -- say a stainless steel mesh at 50 micron, and I'm having dust build up on it, can I use static electricity to remove the dust? I have another mesh that's 500 micron, and ...
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0 votes
2 answers
4k views

How to choose a cut-off frequency by interpreting FFT

I have a question concerning low pass filtering of IMU acceleration and gyro data. To choose a reasonable cut-off frequency, I thought about making some observations in the spectrum. Now I have some ...
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8 votes
2 answers
6k views

Why aren't there any 400V ultracapacitors?

I thought that ulracaps could be better than electrolytic ones for filtering after a bridge rectifier in a compact switching power supply due to their higher energy density. But, for some reason, I ...
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2 votes
2 answers
1k views

What happens to Filtered High Frequency Noise?

How to filter out high frequency noise from power supplies has been covered ad nauseum, but no one ever discusses what actually happens to the noise itself. Surely it doesn't just disappear? My ...
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0 votes
1 answer
4k views

How to filter a signal through a differential amplifier

An input signal must be scaled and biased for an ADC (MCU is TMS320F28027). I following an answer for a previous post. Figure 1: Original answer If the signal needs to be filtered with a cutoff ...
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0 votes
0 answers
63 views

Speaker Cross-Over Network and Power Design

I have some speakers I want to drive from a single output: a 4Ohm 300W Subwoofer, a 6.44 Ohm 60W Midrange, and 2 8Ohm 3W Tweeters. All ratings are RMS. I know that if I were to wire all of these in ...
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2 votes
2 answers
2k views

Is possible compute the bandwidth of a Narrowband Twin-T Passive Notch Filter?

Exist any function of R and C, for calculate f1 and f2 at figure below?
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1 vote
4 answers
3k views

AC through Inductor

I know that Inductor opposes an instant change in current direction. But it is used in AC circuits and in low pass filter circuits. It's a little bit confusing for me. If it resists instant change in ...
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3 votes
2 answers
7k views

Calculation of ripple voltage after rectifier (equation from TAOE)

I am reading The Art of Electronics, Third Edition by Paul Horowitz and Winfield Hill but I feel like I am missing something when the book comes to talk about (begins to, instead) Power-supply ...
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  • 836
1 vote
4 answers
326 views

Unwanted voltages in inverter

simulate this circuit – Schematic created using CircuitLab At the top is a schematic of an H-bridge that I built. Im conducting experiments where I attempt to use it as an inverter. I built a ...
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  • 3,047
0 votes
3 answers
450 views

Active Filter and Sine to Square Conversion Issues

Background: I am currently using a SparkFun Electret Microphone and am needing to both filter and amplify the signal before turning it into a square wave to be interpreted by a FPGA. The mic itself ...
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0 votes
2 answers
89 views

Smoothing sparsely sampled signal

I am looking for a method to smooth a very sparsely sampled signal, which is shown below. Digital filters did not work very well, because for achieving an acceptable smoothness of the offset, the peak ...
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  • 309
3 votes
2 answers
527 views

Killing Kickback with capacitors

I am having some problems with an active rectifier (AFE unit) that produces a 8 kHz and a 50 Hz component on my DC. We have bult in a normal standard Low-pass filter that deals with the 8 kHz, so no ...
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1 vote
4 answers
4k views

FIltering ADC input

I would like to filter signal on ADC input. My question is if I can add before input ordinary RC filter. I suppose that this is not good idea. I have to limit number of operational amplifiers on the ...
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  • 153
1 vote
5 answers
2k views

Stable output from a potentiometer [closed]

A recurring problem with analogue potentiometers is to get a stable output that only changes when the pot is actually moved (i.e. it doesn't output a lot of extremely similar values due to noise or ...
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