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

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2answers
47 views

Power supply noise caused by external heat pad

I have a circuit that switches a 50W Sunbeam heating pad via a relay (for regulating temperature). My circuit is driven by a 5v AC/DC switching converter. The AC input to the power converter is shared ...
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2answers
73 views

Simulating accelerometer noise

I would like to create a software simulation of an accelerometer (MPU-6000). As part of that simulation, I need to model the noise on the accelerometer signal. According to the datasheet of the chip, ...
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1answer
30 views

Does NI Multisim simulates op-amp input and output noise?

I just created a circuit with AD620 in-amp and I'm worried that there is not enough noise. I wonder if Multisim simulates advanced op-amp/in-amp properties, like input noise and such? I mean, if I ...
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3answers
168 views

the causes of Fading of signals

I have read about fading of signals , and I have notice that the major cause of fading is multipath , but I have ask myself , what about attenuation , noise and free space loss , all of these make the ...
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1answer
31 views

How much is the noise of a multiplexer for analog inputs?

I have 4 sensors, each have with two differential output (S- and S+) that I need to use in a differential amplifier (with a gain equals to 1000 in my case). The difference between S- and S+ is ...
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0answers
42 views

Demanding design on bandpass filter/ Notch filter with gain

I have posted a related question before, which can be found here: Very low noise high pass filter design However, since a different stage is to be considered, I started this new post. We are not ...
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4answers
149 views

Very low noise high pass filter design

We are trying to design a high pass filter, which mainly goals are: very low noise. Low noise is the first concern. suppresses 1kHz by around 50dB and passes 2kHz. Gets rid of DC Dont care on other ...
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1answer
55 views

How to filter low frequency noise on power supply from ChipCorder?

I've built a circuit using an ISD4003 ChipCorder, which is an IC for recording and playback of audio (in a telephone answering machine, for example). I've written code to send the SPI commands to ...
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3answers
253 views

Fighting overshoots/undershoots using ferrite beads does not help?

I posted relative problem a while ago here but we came to conclusion that the overshoots were just artifacts. Later, when I extended the signal lines, the overshoots increased and were about 2V of ...
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1answer
89 views

Will motors cause more noise when connected to a ground plane instead of directly to batteries?

I am making a small robot using an Arduino and two servo motors. There are two ways that I can provide power to the motors: 1) Run power and GND wires from the battery holder to the motors, then ...
0
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1answer
38 views

Is the Delay in Strain Data Due to Capacitance?

I have designed a sensor board which gives a strain o/p based on wheatstone bridge principle(change in stress is measured through change in resistance). But the starting value is not at zero level,it ...
4
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1answer
90 views

How can I track where this 471kHz noise is coming from?

I'm new to EE in general and I just received my first oscilloscope (Rigol DS1102E). Anyway, I'm building an audio circuit using an Arduino Micro and the infamous ...
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1answer
178 views

Clean DC power design for very high precision circuit

We have been designing a very high precision control circuit for quite a while. And we are thinking to make it much easier to use, which is to get rid of the Lab DC Sources and use AC to DC switching ...
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1answer
97 views

Curious noise on FPGA Microcontroller connection

I have the following setup: An FPGA eval board has a daughterboard with pin headers connected to it. From these headers I have connected 16 ~10 inch 24-gauge wires to feed a bus to a TI OMAP-138 ...
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2answers
120 views

Filter 50Hz hum picked up by the oscilloscope

I am measuring huge 50Hz oscillations on my oscilloscope, but I am not entirely sure the probe is generating those by behaving like an antenna (an ADC at the same point gives stable values but it's ...
3
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1answer
63 views

Can unwanted coupling drive signal lower than intended?

Let's consider the following schematics- a switch connected to microcontroller's input with internal 50kOhm pullup resistor. simulate this circuit – Schematic created using CircuitLab ...
3
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2answers
71 views

CMOS 4066 Question

This is my first post here and I have a question about a CMOS circuit I have been designing for I while using the 4066 (I'm a noob to digital electronics). I am using a 4066 to pass random pulses I ...
1
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1answer
69 views

Reading noise from allan variance plot for MEMS sensor per IEEE Std 952-1997

I am following the Standard Sensor Performance Parameters from the "MemsIndustryGroup" to test some Gyroscopes: I conducted a test and plotted the square root of AVAR (Allan Deviation) against Time ...
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4answers
67 views

MOSFET gate grouding via LED - noise

simulate this circuit – Schematic created using CircuitLab I use D1 to visually indicate the active transistor. However, gate pin acts as if it were floating. What is wrong with my ...
2
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1answer
73 views

Ground noise measured on scope

I've connected a scope probe directly to the ground clip of the scope. I then observe the signal on the scope and it's reading 0, as expected. I set my trigger to be 1V above the 0V reading it ...
1
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1answer
63 views

Thermal Johnson-Nyquist Noise Generator

I have no background in electrical engineering so please bear with me. I want to create a random number generator/displayer using a resistor. My idea is to wire a resistor to an amplifier of some ...
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0answers
83 views

USB battery charger noise in an audio amplifier

As the title says, I'm having some issues with battery charger noise and an audio amplifier. The PCB with the charger and amplifier is connected to a GSM device, and that's where the audio signal for ...
1
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1answer
52 views

Thermocouple on a grounded stainless steel box

My present project is a ~6kW switching converter in a sealed stainless steel box. The box is grounded well. When I put a thermocouple on the surface of the box, the reading is noisy. Even if I put ...
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2answers
53 views

Sporadic Clock Signals from Momentary Switch

I'm having trouble using a NO momentary switch to send clock edges to a J-Kbar flip flop, specifically the TI CD74AC109E(datasheet). I have a switch between +5V and the clock pin, and also added a ...
18
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2answers
1k views

Why does connecting a high-current device to my digital circuit cause weird behavior?

I have a arduino microcontroller other digital thing and when I connect a motor pump heater other high current thing I experience weird ADC measurements reboots crashes errors in digital ...
2
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2answers
97 views

noise caused by square wave signal

I am using electronic switches to create non-TTL square wave clocking. The oscilloscope graph demonstrates two measurements: Yellow signal: 0-8V Blue signal: 0-5V As you can see, yellow signal is ...
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2answers
103 views

Reduce gear box and DC motor noise

I'm working on a project where I use DC motor and gearbox to reduce the speed and get a higher torque. The problem is, when the project sit, for example on a table, the noise is amplified. (with ...
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2answers
123 views

Extremely noisy signal after voltage follower/buffer [closed]

I am trying to create a voltage follower for my CCD linear array. When I measure the signal with oscilloscope directly from the CCD outptut - the signal is reasonably clean. However, when I measure if ...
2
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2answers
166 views

3 SMPS in one board

I'm doing a PCB where there are 3 SMPS: one boost(12v to 48v, 1 amp max) and one buck converter(5v to 4v, 4 amps max) functioning at the same frequency(same timer in microcontroller). the other ...
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1answer
121 views

What might cause coaxial cable noise?

In my A level physics I recently did an experiment to find what the optimum frequency to send a digital signal through a RG58/U Coaxial Cable is. My results are available on Dropbox. What I found was ...
2
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1answer
56 views

Why is this LPF design passing frequencies above resonant in such magnitudes?

It's been a while since I have worked with filtering so I decided to simulate a circuit to see what I had forgotten. I used MultiSim for my circuit simulations but will present the design using the ...
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0answers
40 views

The origin of contact noise?

I was trying to measure the noise of a device with metal probes. I was not sure whether I should trust the results because I was told contact noise might contribute to some degree. I am a little ...
3
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2answers
176 views

USB line noise in aircraft cockpit recordings

I'm a pilot and we have a comm setup that I need some help with because of noise. We have a USB cable that supplies power to one of our GoPro cameras mounted in the cockpit. When this cable is plugged ...
2
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1answer
162 views

Audible noise in DC-DC buck converter

In my design, I have a +3.3V SMPS that provides power to digital circuits (microcontroller, EEPROM, etc.). The microcontroller allows applying a 100Hz PWM signal with variable duty cycle and with an ...
3
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0answers
76 views

Horrible noise after plugins power to my laptop plugged into effects chain [closed]

I'm using some stompbox effects with my guitar. I'm comparing them with my laptop where I have few VST effects. Everything sound clearly until I plugged power supply to the laptop. Then horrible noise ...
0
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1answer
143 views

Detecting location of infrasound noise in a building

I am working in a large office building with a lot of people. Pretty frequently there is a very weak and low frequency noise that is very irritating. Unfortunately, I have found just one other person ...
3
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1answer
135 views

Origin of micro Hz noise signal

Latetly we recognized a parasitic signal in our voltage measurements. It is a perfect sine wave with a period of a few hours (f = uHz). What could be the origin of such a signals? Ok, a few more ...
2
votes
1answer
90 views

AM radio interference with class A amplifier

I am using a class A amplifier constructed around an NPN Darlington transistor (BC517) because the gain I was getting with a single NPN transistor was nowhere close to what I needed. The transistor is ...
3
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2answers
171 views

Can I use ferrites for the ground connections?

I may have an issue with conducted EMI through the ground connections between devices in a system. There is specifically a device which clearly creates noise on the measured signal from another ...
1
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1answer
147 views

Noise reduction in physiological measurements (EEG/ECG) [duplicate]

I am building a hobby EEG and I am interested in quantifying how effective are the various noise reduction techniques. The basic circuit would be two electrodes going to an instrumentation amplifier. ...
1
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1answer
156 views

Strange noise on DDS

I have built an FPGA based DDS (fc=200MHz. out: 0-50 or 0-80 MHz) . I have a decent DAC output wave and now trying to build an appropriate filter for it ( Fig-1 ). The filter works rather fine but ...
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2answers
99 views

How do I leave electrical connection of heat-sink body?

I usually see that some heat-sinks have thick pins to solder on the PCB, and I'm going to use one of them. Since they are going to be soldered on the PCB, the question rises in my mind about their ...
3
votes
1answer
157 views

What are some techniques to lower noise on a mixed-signal analog-to-digital converter board?

I'm building a 24-bit ADC board for Arduino that can sense microvolts (biological signals). What are some good techniques to lower the noise that will negatively affect the ADC resolution? What I've ...
2
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1answer
127 views

thick waveform in oscope [closed]

I built an oscilliscope with ARM and internal ADC (Atmel), but my signal is very thick (noisy). It looks like this link, but sometimes worse! Could the ADC be outputting noisy values? What could be ...
4
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4answers
98 views

ADC RMS Noise (11nv@4.7Hz)

What is ADC RMS noise? It would be helpful if someone could theoretically explain ADC RMS noise.Say a ADC has RMS noise of 11nV@4.7Hz.What does that mean?
1
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1answer
56 views

Using ADC AD9057

I use AD9057 with fpga in my oscilloscope project. Here is the ADC pin-out I use the following scheme to test ADC: VREF OUT connected to VREF IN, this gives internal reference voltage +2.5V Vd ...
3
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1answer
97 views

How can I tell what type of capacitor to use with an electric motor, if any?

I understand capacitors are used to reduce electronic noise from motors. I bought a little 4-motor car chass off of ebay and I wanted to know a) Does this motor already have a capacitor built in to ...
4
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3answers
608 views

What are the units of RSSI, noise and SNR as defined by IEEE 802.11?

I'm a CS graduate, but to my shame have very limited knowledge of electrical engineering and especially antenna theory. As far as I understand, RSSI determines quality of how measurer "hears" the ...
1
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1answer
53 views

Low noise High current regulator

I'm trying to convert 11-16 Vdc to 5 Vdc @ 3 A to run an array of low-impedance ratiometric sensors. The outputs are going either directly into an ADC or amplified through an instrument amplifier. ...
0
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1answer
86 views

ATMega32, Using PORTA as digital io has digital “crosstalk”

I have multiple switches connected to portA on an atmega32. They are set as an input with internal pullups. There are no external pullups. The switches ground out the pins. I'm not debouncing the ...