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Questions tagged [noise]

About issues caused by electrical noise, or improving the Signal/Noise ratio of an analog circuit.

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30 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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1answer
70 views

Noise on my oscilloscope when probing a wire

I am prototyping a NTC voltage divider circuit and I am having trouble with noise on my probe. It seems like I am constantly getting a large amount of noise (200-300mv) on my oscilloscope waveform ...
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1answer
44 views

Crosstalk between AC and DC

First time asking a question but I've come across something I just can't find the answer to. Whether or not it's because a silly question I hope to find out. So I understand that with crosstalk ...
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0answers
22 views

Noisy Signal over FFC

I have an FFC connector between a Raspberry Pi camera and a PCB which is in turn connected to a Raspberry Pi. The signal over this is noisy and usually causes the RPI to freeze when I try to take ...
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0answers
50 views

How do I get rid of switching noise from these types of DCDC converters?

I am using a lot of these types of isolated DCDC converters for measurement circuits: https://power.murata.com/data/power/ncl/kdc_nmv.pdf The problem is they introduce so much switching noise. I try ...
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1answer
23 views

Initial noise prior to square pulse

I have a high voltage system (~5kV) to generate pulsed spark. I was able to detect the spark ignition. It has been shown in the images by the yellow line. This signal will be used to generate another ...
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2answers
75 views

Ferrite bead for high-speed digital IC

Although I've seen numerous recommendations for the use of FBs on the power supply rails of noise-sensitive analog circuitry, the opinions regarding their use with high-speed digital circuitry are ...
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1answer
49 views

Connecting bandpass filter to comparator generating excess noise

I have a band pass filter with a center frequency of 100kHz, a bandwidth of 10kHz, and a gain close to 1. Input signal is 100mV-150mV peak to peak with frequencies varying from 80kHz to 120kHz. I am ...
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2answers
147 views

How can I remove 1.4MHz and 150kHz switching noise?

(Please excuse my English) I have two types of DC-DC step-down(buck) converter modules, and the switching frequencies of the converter modules are 1.4MHz and 150kHz each. The two converter modules ...
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0answers
31 views

Touch screen smartphone stops working during charge [closed]

Goodmorning everyone, I'd like to ask a question about a fact that happened yesterday. While I was charging the smartphone through an "unofficial" charger, I've noticed that the touch screen stopped ...
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0answers
23 views

Unwanted buzzing and reduced volume in a basic speaker set

I have the following device, which basically contains 18 songs. we can play the next song by switching the switch on and off. It also has a volume control. Recently it started to buzz a lot and the ...
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2answers
96 views

How to separate ground efficiently in a thyristor circuit controlled by sensitive microcontroller

I've been trying to design capacitive discharge ignition circuits using a microcontroller ARM (Texas and ST) without success. Each circuit using them presents intereference problems during spark ...
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0answers
53 views

How to reduce spike in Power Supply and GND (SCR + Ignition Coil)

My circuit: Signal coupled in power supply (3.3V) of STM32F103 during spark: Is there any benefit to using this diode (circled in red) or not (without this diode the snubber circuit will start ...
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1answer
50 views

Estimation of signal from noisy data

I am designing a PID controller for my beam steering application. I have lateral position sensor detector (PSD) PSD LINK to detect the position of beam. The problem is that the output of sensor seems ...
2
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1answer
56 views

What effect does a logic analyzer probe have on a circuit?

I have an MCU controlling a LED sign. This sign speaks the HUB75 protocol, which is essentially a large shift register. Being a shift register, this requires a clock signal to be generated, which the ...
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1answer
35 views

Link between phase noise and linewidth for a oscillator?

I was googling for a formula to transform the dbc/Hz value given in data sheets for VNA, spectrum analyzers and VCO is often given in dBc/Hz with offset. Now looking up research papers about future ...
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1answer
70 views

Reduce Noise Added With Zener Clipper

I'm working on a hobby Arduino project to create an audio visualizer using an LED strip. I'm using the MSGEQ7 to separate the signal into 7 bands, then send it to a Wemos D1 Mini. I started by ...
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3answers
63 views

perceived loudness of noise vs. sine wave

I am trying to understand what gains I need to use each for a white noise generator and a pink noise generator for a human ear to perceive the loudness to be the same as it is for a 440 Hz sine wave ...
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4answers
141 views

Linear Regulator PCB placement

I'm designing a PCB with some noise-sensitive components (FPGA, RF mixer, etc.). For the power systems I've decided to chain switching regulators to LDO regulators so that I get less heat dissipation ...
2
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1answer
65 views

Noise generator with LM318

I want to build a noise generator from a Zener diode. I designed the above circuit. The noisy voltage from the diode is filtered via a high-pass filter and input into a 92x gain non-inverting ...
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0answers
27 views

What is the ENBW of a Sigma-Delta ADC?

How do you determine the equivalent noise bandwidth (ENBW) of the digital filter in a ΣΔ ADC? For an analog filter of known order this is straightforward, but, is there a way to estimate the ENBW of a ...
2
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1answer
39 views

Noise addition. Sum of shot and thermal noise

The situation is as in the picture. I've made the resistance small compared to that of the tunnel junction so the thermal noise of the tunnel junction can be ignored, since the thermal noise in the ...
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3answers
80 views

Why does low power factor make my LED bulb and clock radio flicker at 0.2 to 3 Hz?

[California, USA, regular 110 V power.] I'm reading the power factor of my "Late 2013" 27-inch iMac using a P3 P4400 Kill-A-Watt. It reads 0.95 when operating normally (60 to 120 W), but when ...
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1answer
113 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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1answer
45 views

Multimeter across Power Line voltage varies wildly

I'm building a single switched AC/DC Forward Converter and have reached to the point where I have steady o/p voltages and currents. However, I am not able to remove noise that goes back into the AC ...
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1answer
38 views

ADC wire is picking up noise from cellular antenna [EMC]

I have a 5 wire micro jst cable with a line for ADC readings from an IR sensor that is picking up interference from the cellular antenna of the microcontroller. Will I be able to reduce this noise if ...
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1answer
24 views

Mixed digital/analog rails and level-shifting components best practices

I am designing a board with a ±2.5V analog domain and a 3.3V digital domain where space is at a premium. Digital and analog grounds only connect at a single point near the supplies. As such I am using/...
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0answers
58 views

STM32F4 ADC oscillating

I am trying to read the ADC of a STM32F4. The code skeleton was generated by CubeMX, the HAL library is used. The read values are feasible but have periodic noise, as seen here: The plot was ...
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0answers
44 views

Gyroscope drift in IMU

So, a brief foreword. I'm not sure if this question belongs here or in the DSP community, its closely related to both, but I have a feeling this will be more of interest here nonetheless, so I am ...
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2answers
128 views

Opamp noise: When is a resistor in the signal path?

I am confused as to when a resistor is considered to be in the signal path and when its not when it comes to opamp noise calculations. For instance, take the following circuit: simulate this circuit &...
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0answers
36 views

How to reduce noise caused by interaction of two power supplies in a circuit?

This question is related to MEMS (micro-eletrical-mechanical-engineering), please allow me briefly introduce the actual background of this question. Background I found an interesting displacement ...
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2answers
70 views

How close to a stepper motor do I need to shield the wires?

I am trying to shield the cabling on my CNC mill. The motors, unfortunately, do not have connectors but instead have wire leads coming out from the motor housing. I can cut those wires about an inch ...
2
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3answers
74 views

Oscilloscope averaging and standard quantum limit

Oscilloscopes give a Vrms noise and have a noise floor, but if I average for a long time to infinity, am I at the standard quantum limit and does SNR keep improving with the sqrt(N averages) forever?
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23 views

Can I control a Sanyo Denki fan to operate with uniform noise?

I bought this replacement Sanyo Denki fan for my air purifier. The sound out of that fan is louder than the other two pre-installed fans. The original fans mfg is out of business, and replacement ...
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2answers
91 views

Strategies to reduce EMF radiation

During a long-term, almost six month long, data acquisition in a proximity of scanning electron microscope I have found a significant source of magnetic field noise, which is altering the results. I ...
2
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1answer
71 views

Sound sensor not working when connected to DC motor

I made a small circuit to control a DC motor with a sound sensor, using an ATtiny 85 and an L293D. It worked on breadboard, but now that I have a prototype PCB it ceases to work. Whenever I connect ...
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0answers
24 views

Noise on Input Buttons for H-Bridge

I'm constructing an H-Bridge to control a linear actuator. I've done so by using a 2-channel relay module, some buttons, and a ESP32. I do not believe this is an issue of debouncing as I account for ...
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3answers
99 views

Decoupling capacitors introduce more noise on transmitter power amplifier

I have an issue that I can't understand and looking for your help to give me some insight to solve it. I'm using a module named dw1000 that is used to measure distance using UWB at 6.4Ghz, 3.95 Ghz......
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1answer
74 views

What's causing the audible 7/8th rhythm in Qi chargers?

I have a wireless Qi charging system for my mobile phone. When I put the phone into the cradle it starts getting charged and I can hear a very quiet noise coming from the arrangement. Other ...
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1answer
93 views

Noise Temperature of Antenna [closed]

A microwave receiving antenna on a satellite is pointing towards the earth. The antenna beamwidth is 50 degrees, the earth subtends 5 degrees at the satellite. What will be the noise temperature of ...
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1answer
104 views

Prevent small signal with noise

I am designing a Conductivity Meter by using Arduino. I used ad9850 to generate a sin wave with 1khz and peak to peak 20mV. but there is a bit of noise with my output Signal and after the voltage ...
2
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2answers
215 views

Bose QC20 in-ear headphones 50Hz buzzing noise on PC

When I plug my Bose QC20 on the PC, I hear a low volume 50Hz buzzing noise. Some interesting facts: When I touch a metal part (PC case, keyboard) the noise is gone. I have this noise on all USB ...
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1answer
53 views

What's the source of this noise in my Arduino oscillator?

I've been experimenting with techniques to rapidly switch on and off the digital output pins in an Arduino. This is the code I use: ...
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2answers
74 views

Troubleshooting TL071 to TA8207 100 Hertz hum

I worked out to build a pre-amplifier connected to a power driver in a single setups(a pcb). Problem arises when it's powered up. here are a few questions. Setup has a TL071CP as preamp with a unity ...
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0answers
72 views

How can I eliminate the noise in this case?

As a part of a big system Arduino is being affected from a switch outside(so the spike is not always there only when an outside switch or surge happens ect.) and I guess through its USB producing ...
4
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1answer
99 views

How to reduce noise in SMPS (Switching mode power supply) circuit

I am just using a reference design of SMPS (from Microchip) to boost input voltage from 12V to 90V as the image below: It's working normally but the problem is the noise at the output of 90V. I ...
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1answer
45 views

How can I model a circuit for this noise coupling phenomenon

A shielded Wheatstone type force transducer FT is mounted on a metallic structure and through its cable is connected to an industrial amplifier module Amp(I gave the names in the below illustration). ...
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1answer
48 views

How phase modulation changes spectrum?

I'm studying amplitude,frequency and phase modulations for an exam. I just studied amplitude and frequency modulations, however i didn't succeed in understanding how the phase modulation changes the ...
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1answer
58 views

Splitting an Analog Signal Without Adding Noise

I am trying to take a current measurement, run it into a PCB that splits the signal, and then output the signal in two places. One of the destinations is a RIO being used for feedback control, the ...
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0answers
24 views

smps power plane

I am designing an ultra low noise SMPS with 4 layer PCB. On the first layer I have components and power traces. On the second layer I have a whole GND plane. My question is: for the 3 plane (power ...