Questions tagged [noise]

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

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1answer
34 views

Would leakage through a JFET create thermal noise

The impedance through the gate of a JFET is very high and leakage current very small. Would this impedance act like a large resistor creating thermal noise? Would this be a low noise way of ...
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1answer
26 views

What is meant by the term “baseline noise” in this context?

I came across this article about oscilloscopes. Under the figures and scope screenshots there is a term called "baseline noise". I googled but it turned out this baseline noise is used at different ...
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4answers
2k views

Do I need a 50/60Hz notch filter for battery powered devices?

Given that battery powered devices are not plugged in the mains power, can I assume that there will be no 50/60 Hz frequency noise? This question came up while thinking about what the circuit for a ...
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0answers
36 views

Is there a (sane) way to diagnose and resolve these EMI issues? [on hold]

A friend sold me their vintage turntable and receiver. Turntable is a Philips 437, Receiver is a Scott 355R. For reference I've listened to this exact setup at their house and never noticed issues, so ...
4
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1answer
63 views

Downsides of 3-terminal capacitors and LC filters for power supply to IC

I read the Murata application notes on power supply decoupling and noise filtering. I guess it works great as advertisement because I now want to replace all the decoupling capacitors to my analog-...
0
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1answer
40 views

summing amplifier output

i amplified 2 audio signals using lm386 ics separately,and gave both the outputs as input to ua741 ic,to be used as a summing amplifier.I am not able to get any output at the speaker from ua741,not ...
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1answer
75 views

TSOP34838 noise in dark areas

I'm using a TSOP34838 IR reciever on an ATMEGA MCU, However, I see a problem in dark areas... If I put my finger in front of the receiever, it starts spewing out garbage, even worse when the room is ...
2
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0answers
57 views

How to remove DC power supply noise while load is active?

I'm using a breadboard power supply to power up two STM32F103, two Hall flow sensors, one IC555, and one 16x2 LCD with backlight. While everything is connected I have alot of noise in the system which ...
6
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6answers
2k views

Why does this potentiometer in an op-amp feedback path cause noise when adjusted?

I have placed a dual-gang 100k potentiometer in the feedback path of two op-amps that work as a Sallen-Key filters. This controls gain but also the Q factor of the filter (somewhat demonstrated on ...
0
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1answer
25 views

Does the probability distribution of cosine transformation of uniformly distributed R.V. depend on phase shift of the cosine function?

Suppose, x is uniformly distributed over [0,2π], and y = cos(x + ∆), will the probability distribution function of y depend on ∆? Is my solution to find out the Probability Distribution function of Y,...
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0answers
22 views

How to reduce noise for arduino capacitive sensing

I have an artistically-painted 5mm-thick wood panel that I want to use as a light switch without alteration to the image. My solution was to (try to) make a specific region on the panel touch-...
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3answers
57 views

Frequency/amplitude modulation and SNR

I read (for instance here) that FM modulation is less affected by noise than AM modulation. But I don't understand conceptually the reason for that: why is the SNR with frequency modulation higher ...
6
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2answers
228 views

How do wireless receivers reject noise created by the original signal reflecting off walls?

When a transmitter emits an RF signal it reflects and bounces around all over. If a receiver is line-of-sight with that transmitter then the original signal will hit it first but signals bouncing off ...
0
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1answer
46 views

LED Strips - Data Noise Over Long Distance Between Controller and First Strip

Please refer to the above picture. The black line is the ground wire and the green line is the wire carrying data. First Question In regards to data noise/interference, can the output ground wire ...
0
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1answer
32 views

Does swapping the inputs cause increase in the common mode noise in this scenario?

This is a question I wanted to ask after I have observed much more noise when I swap a filtered traducer's output to a single ended data acquisition board. A transducer outputs Vs1 signal. The ...
0
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1answer
88 views

Noisy op amp buffer

I made an op amp buffer using a TL071 for my guitar but it is very noisy. The circuit is a simple follower. Originally I had no feedback resistor but I added it later in case it decreased the noise ...
1
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1answer
67 views

Noise in portable power supply to guitar effects pedals [closed]

I am constructing a battery powered power supply for a guitar effects pedal board. There are 5 pedals and I am using a phone charging battery and a boost converter to supply 9V (centre negative) to ...
0
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1answer
74 views

Removing noise from TDA2007A Audio amplifier circuit

I have built an audio amplifier circuit like the test circuit in this TDA2007A datasheet I am going to use this circuit with Raspberry Pi 3B+ and going to feed sound via 3.5mm of Raspberry Pi to this ...
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1answer
25 views

Confusion with applying incremental bandwidth to measure noise power spectral density

From a text, regarding the following paragraph about random noise: Being not very informed on this topic, I don't understand what meant by the following statement: "If such a measurement is made ...
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0answers
39 views

How does one calculate output voltage noise of a current output DAC?

I am using a current output DAC connected to a voltage reference and a transimpedance amplifier. I know the noise characteristics of the voltage reference and the amplifier. The DAC simply lists "13 ...
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0answers
31 views

Low-Speed CANbus Common-Mode Choke Insertion Loss

I'm designing a low-speed CAN transceiver breakout-board (schematic below) and I'm trying to select the proper choke to use to reduce common-mode noise. I've found a few common-mode chokes meant ...
3
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0answers
50 views

Differentiator circuit sees noise on PCB after 2 min

I'm new to PCB design, and looking for some advice. I designed a PCB shield and I'm seeing a lot of noise in my differentiator circuit. The circuit will run perfectly for about 2 min and then all of ...
1
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1answer
40 views

Series regulator noise levels

When using multiple regulators in a chain, is there noise added to the input by the regulator? If I have a SMPS feeding an LDO, and then another SMPS after the LDO. Is the ripple or noise added to ...
1
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1answer
76 views

Triac dimmer makes audible noise (hum or buzz)

I have some triac dimmer from IKEA (bought several years ago). This dimmer makes audible noise (hum or buzz), very notable during night when it is placed on a bedside table. I failed to find the ...
1
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0answers
82 views

RC filter for UART

I am working with a device. Block diagram looks like this: I was facing a noise challenge and asked a question here. I implemented the RC filter design suggested by @analogsystemsrf and got good ...
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2answers
135 views

Filtering power supply noise

I am getting 7 volts from a power supply source which I need to step down to 3.3 V for powering up my 2.4 GHz zigbee MCU (TI CC2530 + CC2592 amplifier). I am using a linear regulator to step it down. ...
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0answers
25 views

Noise power of attenuator-amplifier cascade

Lets say we have matched circuit that consists of attenuator and amplifier in cascade and that this circuit is subjected to a noise from an outer source whose effective temperature is T. Find ...
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0answers
36 views

Practical method to measure a data acquisition board's noise floor

Noise floor of a 16 bit system is usually within a few dB of 96 dB. And this is because 20*log10(2^16) = 96dB But I guess this is the theoretical quantization noise floor. So if this was the only ...
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0answers
17 views

How does electrical noise affects signal and distribution power?

What is electrical noise and mechanical noise How does it interfere with power? - signal power - Power distribution/ transmission
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0answers
35 views

Noise for a switched capacitor circuit

I have a switched capacitor circuit that looks like below: It operates at 80MHz to realize a 625k resistor. It works fine in the circuit. I tested with VDAC(input)=1.8V and the voltage at the right ...
1
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1answer
98 views

Matrix of small incandescent lightbulbs - problem with buzzing

I am prototyping a circuit for controlling matrix display of small incandescent lamps with Arduino (each lamp is 6.3V 0.3A). I designed the circuit in Yenka and built it. It is composed from 3 types ...
4
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1answer
178 views

Difference Between RMS noise and PSRR in an LDO

I am trying to choose a low dropout linear regulator to partially smooth the output of a dual rail SMPS I'm using to power analog circuits. I'm confused about the difference between the specified RMS ...
0
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1answer
32 views

Electrical noise on wemos D1 mini

There is electrical humming sound coming from wemos D1 mini v2 module. I'm using 5v 3A power supply connected to 5v input pin. I suspect its the current input which cause sparking/humming sound. ...
0
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2answers
47 views

How to filter/clamp/suppress positive voltage spikes from IC

I need to work with an IC or more specifically a PCB (RFID reader) that is feeding back positive voltage spikes into my supply line. What is the generally accepted solution of isolating noisy IC's ...
7
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3answers
473 views

resolution bandwidth

I have the following trivial question: I have acquired a noise spectrum with a resolution bandwidth of \$124\mathrm{Hz}\$. I would like to convert it to \$\mathrm{V/\sqrt{Hz}}\$. Shall I simply ...
2
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2answers
83 views

Johnson-Nyquist noise for a lossy inductor?

In searching the internet for thermal noise on an inductor and I'm not finding much on the basics for a real lossy inductor. I'm interested in thermal noise for a fixed inductor in a surface mount ...
0
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1answer
56 views

Low pass filter vs low noise regulator

I’ve been spending a lot of time looking at different low noise voltage regulators, and it dawned on me-why am I not just putting a filter on the output of the regulator I already have? What are the ...
0
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1answer
64 views

schmitt trigger causes noise

I am trying to get a 74HC14 hex inverting schmitt trigger to work. First thing I did was connect it to a power supply. When I connect the Vin and Ground ports to my bench power supply (5V), some ...
3
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1answer
82 views

Headphone Noise from Laptop SMPS

I have been facing an issue that has been a mystery to me for quite some time, and I wanted to see if someone here can potentially give me more insights on this so I can understand why it is happening....
2
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2answers
98 views

How to reduce thermal resistor noise in filter circuit?

I'm taking some measurements from a bio-sensor (using an INA) that operates on the a few to \$100\ \mu V\$ scale. Because of 50/60 Hz EMI, I plan to apply a notch filter (NF) of the Twin-T or the ...
0
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0answers
42 views

Reduce wake-up noise on ARM CM3

I need some help exploring a solution. I have an ARM Cortex M3 MCU, which has low-power sleep mode implemented. Wake-up sources are any GPIO pin, or an RTC alarm. A terminal is connected to UART-0 ...
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0answers
18 views

Noise in DC/DC Converter QHL600300S12 (180V-425V to 12V) output

We are using a DSO TDS2022B from Tektronix to check output voltage of DC/DC Converter QHL600300S12 from XP Power and were seeing 5V peak-to-peak in the 12V output power rail. What could be the ...
0
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2answers
50 views

Resources on Noise Circuits

Back when I was taking an RFIC design course, I was pretty disappointed by the noise part of the class, specifically calculating the output-referred noise voltage, noise figure of an amplifier, etc. ...
0
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1answer
64 views

Relaxation Oscillator Issue, comparator self-oscillating at 25 MHz (40ns propagation delay)

I have a relaxation oscillator circuit, which is supposed to oscillate around 6 MHz, and mostly it oscillates in a very stable manner around it. However sometimes it starts to oscillate at 25 MHz, ...
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2answers
31 views

Noise testing method

I have Electronic board with power supply , control board etc. I wanted to conduct noise test . Is there any standard procedure available. I wanted to check if i induce the noise into power line or ...
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2answers
122 views

Mcu keeps reseting because of noise

I have a circuit in which there is a mcu lpc1768 and a gsm module sim800l. For power I use DC/DC converter and made a 4.2v using lm2576 for sim800l. Used that voltage, I made a 3.3v using ams1117 and ...
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2answers
51 views

How VFD affects an isolated IOT system

To avoid noise from the external system I tried to isolate the internal completely. So I added DC-DC isolated converter with signal isolation. I have attached the picture. Still when reading data and ...
0
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1answer
79 views

Practical considerations for a summing amplifier

The summing (usually inverting) amplifier is a classic op amp configuration. However, I'm struggling to find any products on the market which actually do this, leading me to conclude that I have to ...
3
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0answers
133 views

ADC conversion value spike during ADC conversion

Description of the situation I am trying to get an analog vibration sensor signal to a Raspberry Pi 3 B+. To convert the analog signal to digital values, I'm using Waveshare High-Precision AD/DA ...
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0answers
24 views

PSPICE Error in Second order High-Pass Sallen-Key Filter

As part of a class project, I'm trying to filter pulses with noise by implementing a High-Pass Sallen-Key Filter with the resistors replaced with transconductance amplifiers (schematic shown below). ...