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

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2answers
37 views

Can ground plane EMIT noise?

I have 3 separate grounds in my project: AGND - Analog ground is very quiet, very small relatively smooth currents PGND - Power ground used for power bypass caps and power supply related circuitry ...
0
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1answer
30 views

Mysterious Noise Issue in Automotive Ignition Coil Application, Arduino

I'm building a circuit to count RPM based on watching the negative pole of the primary coil in an old automotive ignition coil. I had no illusions this would be easy, but here I am stuck even though I ...
1
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1answer
84 views

What amount of noise on Vcc is acceptable?

I have added a .1uF decoupling capacitor between Vcc and GND on a TMS9118 (this is an old video display processor). When I measure the voltage at Vcc with my oscilloscope, I read a pk - pk of 1V. Is ...
0
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4answers
74 views

accelerometer interference

I had a PCB containing a micro usb and a 3 axes accelerometer LIS3DH. I put the PCB at fixed position and the value of Z vary between --77at -83. but when I touch the usb cable with my hand or with a ...
0
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1answer
29 views

Smartphone microphone frequency response, ADC and SNR

I'm trying to find on the web if there's an example of smartphone that records with low quality (which introduces lot of background noise) and an example of phone that records with good quality, maybe ...
0
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1answer
22 views

Optimizing regulator power circuit for low noise?

I am trying to understand the attached circuit. It's an ADP3333ARMZ-3.3-R7 regulator to provide 3.3V to an analog system. My goals is to have a very low noise regulator and power circuitry for a 16 ...
1
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1answer
37 views

Changing Direction of twist in a twisted pair (24V 4A)

I have two wiring harnesses one going to my power supply (24V at 5A) and the other harness going to my main board, there is a motor controller on the board so it can draw a few amps. I noticed that ...
0
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0answers
66 views

Right leg driver in an instrumentation amp?

My two groupmates and I are currently rereading a report on a project of ours, and having a bit of trouble regarding the theory behind something we did. In the project we designed an EEG machine, ...
1
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0answers
45 views

What causes periodic noise with LM386 amplifier

I am trying to use a LM386 to amplify an audio signal so that I can listen to it using a speaker. I am using the recommended circuit from the data sheet: When I connect my audio source to the input,...
-1
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0answers
47 views

How to protect your arduino from noise? [closed]

How you can protect your arduino from the noise of the relays without unseparated power supplies?
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0answers
26 views

Troubleshooting HIP4081

I'm driving four N-channel MOSFETS (IRFLIZ44N) with a HIP4081, and the circuit looks like the following: The MOSFETS are driving a peltier module, and the input pins of the HIP4081 are being driven ...
0
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1answer
53 views

Problems with Switching a Solenoid Valve with a Relay

I've been trying to switch a solenoid valve using a relay controlled by a signal from a microcontroller. The circuit works fine when connected to a normal load like a light bulb, but some random ...
2
votes
2answers
81 views

How to minimize hash noise in amplifier mounted near boost regulator

I've designed an audio low power (20W) guitar amplifier circuit whose pre-amp section has somewhat high input impedance, as is best for a magnetic guitar pickup. Since it operates from a battery ...
-4
votes
2answers
74 views

filtering 12vdc power [closed]

I have a power supply that outputs 12 V DC when it is connected to 119 V 60 Hz AC supply. However I am getting high ripple of 1.5 volts peak to peak. I think the power supply circuit already has a ...
3
votes
1answer
36 views

What is the purpose of masking the LFSR value in STM32's noise generation?

I read on section 14.3.8 of the STM32F4 reference manual that you can mask the LFSR output value partially or totally. At first I thought that it was used to change the pseudo random pattern (...
0
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0answers
10 views

Effect of bandwidth change on Figure-of-merit in DSB-SC

I want to ask about Figure-of-merit in DSB-SC. I know that Figure-of-merit on DSB-SC is SNR of input divided by SNR of output, which is for DSB-SC by default is 1. So, I got a problem from my class. ...
-1
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0answers
30 views

Electrical noise

I have made a sensor to acquire emg signal from forearm.But the sensor suffers from electrical noises. When i keep my leg to the floor the noise increases. Similarly when the charger is connected to ...
2
votes
1answer
66 views

Dual Digital Pot With Different Op amps & Layout

I'm using a dual digital pot IC controlled with an SPI interface. Each pot goes to a different op amp on the pcb to calibrate two different voltages. Since both pots are in the same package, how big ...
0
votes
1answer
62 views

My printer injects hum into my USB ports [closed]

I have a Brother HL-L2305 laser printer. I love it. I also have a pair of KRK Rokit 6 G3 speakers that I run off of an MBox 3. Every time I plug the printer into any USB port, hub or not, a loud hum ...
0
votes
1answer
39 views

AYTINYx4 - execute other code during analog conversion

I am using an ATTINY44 in my current project. As I need to do some time sensitive switching I would like to avoid any unnecessary delay. To control another device (not time sensitive) I need to read ...
0
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0answers
48 views

Notes when designing circuits near Noisy Sources (Fluid pumps)

I'm currently designing a data-logger that logs water level of the well ,there is a water pump of unknown specifications that will be near the data-logger but i will not be connected to it in any way, ...
1
vote
3answers
62 views

How to remove noise from power adapter

I am making an audio amplifier using an LM2879. I am using the schematic provided in the data sheet. For a starting point, this design works pretty well, although the base cutoff point could be a ...
1
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4answers
84 views

DC motor causing noise on the power line

I've been building a circuit where I'm controlling a motor using a bluetooth module + phone. I've been having some problems, which mostly are fixed (see topic: previous topic). The main problem I'm ...
0
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2answers
45 views

Is it possible to filter out noise to a pulse counter when there is no twisting or shielding on a long conductor?

simulate this circuit – Schematic created using CircuitLab I have an application where 400'-450' of 14 AWG solid core cable was buried to connect a flow meter to a shed. I built this circuit ...
0
votes
1answer
57 views

Does the physical distance from electrolyc capacitor to inductor matter?

I am designing simple LC circuit (L=470uH, C=1000uF) for 12V / 12A (1 Ohm load): As you can see, I did do some soldering already (without too much or noob thinking). The capacitor and inductor ...
0
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3answers
43 views

Audio Signal Noise: Understanding & Troubleshooting

Today, I'm wearing a pair of active headphones for a change.. ( Running on 2x AAA batteries ). I've hooked them up to a synth and noticed this really annoying monotone buzz / hum in the background. ...
3
votes
1answer
57 views

How can any spectral analysis show that Sigma-Delta ADC reduces quantization noise?

Quantization noise refers to the modeling of the difference between an analog signal and its quantized version as an additive noise process. The power of the quantization noise can be calculated by ...
0
votes
2answers
81 views

How do you get rid of hum in audio?

I built a circuit for a simple amplifier that can use both bluetooth or a 3.5mm connector. The problem is that I am getting noise when I use the bluetooth module. There is no noise when I use the 3....
0
votes
1answer
37 views

DC-LVDT Output noise filtering

I am working with the DC-LVDT Omega 620-25 http://www.omega.com/pptst/LD620.html Manual: http://www.omega.com/Manuals/manualpdf/M4345.pdf Specs: http://www.omega.com/pressure/pdf/LD620.pdf I am ...
0
votes
0answers
31 views

Arduino input noise control

I have been working on a project to simulate a fire suppression system. Below is a brief theoretical picture of what the project looks like Anyhow, the system is set up into a box, and the system ...
0
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4answers
135 views

Exact meaning of dB?

I know that when people say that a gain of amplifier is X dB, they mean that 10*log(Pout/Pin). However, How can I interpret it when they say that "noise floor is -120dB"? How can I derive voltage ...
4
votes
2answers
73 views

How does Hybrid Ground Works?

The text that is above the figure is from my textbook and i am having difficulty to understand what it is trying to say because it's not in detail!! why only remove high frequency and prevent low ...
0
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1answer
43 views

Cut-off frequencies for common mode and differential mode filter?

Attached is the circuit section for the differential signal amplification. The circuit is comprising of common mode and differential mode filter capacitors.So there will be two different cut-off ...
2
votes
1answer
63 views

Noise can be Differential or Common!

I have a basic understanding on this topic but i still have some doubts, my text books says Differential means it will have impact on one of the 2 signal nodes. and Common will have a common impact on ...
0
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1answer
52 views

reducing the effect of a parasitic capacitor!

According to my text book, the second figure says that the noise current returns to their source without flowing through z1, how is that possible? if the noise returns why doesn't signal/ original ...
1
vote
2answers
103 views

Reduce noise in Buck converter:

I'm making a buck converter, this is the circuit I've: The average voltage at the output is ok, but I'm getting lot of noise at all nodes of the circuit: I'm using as a main source a 30V 5A bench ...
0
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2answers
35 views

Noise source in orcad pspice

I have a certain circuit and I want to see its ac performance when I send in certain noise as a signal. is there some option like noise source similar to sine etc signals in orcad.... I can make my ...
0
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1answer
53 views

Less noise when not following LED Driver datasheet

I designed a board which uses a LED driver (datasheet). It clearly states, DO NOT connect DIM- to Vin-: However, these are the waveforms I get on Analog DIM pin when they are disconnected, and ...
1
vote
1answer
117 views

Noise from stun-gun based butane torch ignition spark is locking up ATmega328 microcontroller

I have a stun gun (http://www.amazon.com/VIPERTEK-VTS-989-Heavy-Rechargeable-Flashlight/dp/B00FPE6UN2) which I am using to create a large 1/2" electrical arc through the air to remotely ignite a ...
0
votes
1answer
37 views

Getting rid of electrical noise produced when one touches amplifier and amplifier's dials

I purchased a Lepai LP-2020A+, which is a pretty good little amp for the price, but I've modified it to make it much better and decided it deserved a better casing to look the part, too. So I ...
0
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1answer
63 views

Switching power supply noise and grounding

So I have a +-15 V and a neutral switching power supply. As far as I can see the outputs are floating. The power supply has no earth connection. Voltage from negative terminal to neutral and to ...
0
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0answers
51 views

Do I need to worry about FCC emissions when using PWM?

I have a AC-connected (though an adapter) unintentionally radiating device that runs a large DC motor (12v, ~6a continuous) under <10khz PWM control. Naturally, switching this large a motor ...
0
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0answers
77 views

What LDO has lower noise: AMS1117 or AP2114?

I'm trying to choose a low noise and low cost 500mA to 1A LDO for my VCO project, but i'm having trouble figuring out which of the AMS1117 and AP2114 choices has the lower PSRR noise. Each component ...
1
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2answers
83 views

How suppress bounce-related turn-on spikes in DC bench power supply?

I'm taking a refining pass on my DC Bench Power Supply design. It generally works quite well on veroboard, so I thought I'd move on to SMD PCBs and refine the design while working out a few of the ...
1
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3answers
118 views

Protection For This Circuit

This is my theoretical (haven't tested yet) circuit I have designed for a project of mine. Electrics is a new field for me so please raise flags if my circuit has flaws. Assuming the circuit is ...
0
votes
2answers
100 views

4-20mA Error vs Distance Relationship [closed]

Is there a relationship between noise error and distance for 4-20mA? This noise error could be expressed as S/N ratio, percent from full range, dynamic range, noise density, resolution, etc. Digital ...
14
votes
7answers
2k views

Is there any downside to using a larger than needed smoothing capacitor?

I work with low-power DC voltage regulators. I am already aware of the formula to calculate the size of smoothing capacitor(s). This can be an iterative process of testing one size with a scope and ...
2
votes
3answers
108 views

Mains hum without ground loop

When I hook a device to the monitor input of my digital piano, I get a very noticable 50Hz hum. I understand that the monitor input doesn't have to be particuarly good quality, but it really is ...
3
votes
3answers
190 views

What is the peak - peak voltage of 15mV rms white noise?

I've been experimenting with zener diode based noise sources. I have such a source for which I want to determine the peak to peak noise voltage. I've measured the noise with my trusty multimeter and ...