Questions tagged [noise]
About issues caused by electrical noise, or improving the Signal/Noise ratio of an analog circuit.
0
votes
1answer
45 views
Digital 3.3V switching distances <10m
I would like to know what is a reliable way of sending digital signals over about 5m using a 4 core cable. I don't care for isolation as the micro is only 3 bucks but I know that at these distances ...
0
votes
1answer
72 views
Amplifier Noisy Output (LA4597)
I have a problem with my amplifier circuit (LA4597).
I tested it (12V). It turns on and the speakers and fine and silent.
But when I try to add an audio source (RCA) within the circuit, the speakers ...
0
votes
1answer
43 views
Equivalent noise resistance(s) - 2 stage amplifier
I came across this question in my textbook:
The first stage of a 2-stage amplifier has a voltage gain of \$150\$,
an input resistance of \$1500 \Omega\$, an equivalent noise resistance
of \$700 ...
0
votes
0answers
34 views
What could be the source of this noise?
Below is the output of an accelerometer when it is standing still:
The zoomed 0.5 seconds of time series voltage data above is from a 4 seconds of measurement with a data acquisition board at 30kHz ...
1
vote
2answers
38 views
Amplifier Specifications for Lock-in Detection
Since a lock-in amplifier is effectively a high-precision AM demodulator, what are the most critical characteristics for amplifiers in the high-frequency signal chain? Take a 50kHz lock-in circuit for ...
0
votes
2answers
73 views
10 mV spikes in adc readings
I have a custom data logger attached to a sensor being powered by a solar panel(charge controller and battery). I have a problem where I'm getting 10 milliVolt one sided spikes in my ADC readings as ...
0
votes
1answer
55 views
Common mode chokes in series
I am designing an ultralow noise audio board.
On the first PSU PCB (just talking after bridge) I have a CMC to remove switching noise on diodes to undetectable levels (with plenty of capacitance for ...
0
votes
1answer
50 views
High voltage to low voltage buck converter for(60V IN 5V 3A out) making noises?
I've been trying to convert a high voltage input to a lower voltage (5V at around 3A) with no luck using these Modules
and all of the LM2596HV iteretions of modules out there and all seem to make ...
2
votes
2answers
52 views
Calculating the frequency of data lines?
I read a calculation about determining the bandwidth of USB https://www.edn.com/electronics-blogs/all-aboard-/4425691/Rule-of-Thumb--2--Signal-bandwidth-from-clock-frequency
Roughly what was said is:
...
0
votes
0answers
40 views
Upstairs circuit in house is noisy [migrated]
first of all, I'm sorry if I'm posting in the wrong community. I looked for a stack community more related to my issue but couldn't find one.
Here's my issue: all the outlets on the 2nd story of my ...
0
votes
0answers
18 views
Finding output SNR using Noise figure
am trying to solve this question below:
So I did find the system's overall noise figure to be 2.3 = 3.68dB, and you are more than welcome to verify it. However, my problem now is to find the output ...
1
vote
1answer
60 views
Dealing with coupling of PWM noise into Hall-Sensors as spikes in BLDC driver circuit
I have designed the first revision of a BLDC driver board (based on STM32 and DRV8323 chips). Right out of the bath (after writing the firmware of course) I noticed that the coupling of PWM into the ...
3
votes
1answer
47 views
GSM Interference with Meanwell Switch mode PSU
I am having trouble with interference from a GSM modem and my switch mode PSU.
I do not know much about interference and how the radiation patterns works for GSM. Below is an image of the circuit ...
0
votes
2answers
36 views
Replacement of MEMS gyroscope with better less noise devices [closed]
Is there any good replacement for MEMS based 6 or 9 degree of freedom gyroscope to use with Arduino ?
I read that most of MEMS are not reliable regarding the values, with slow reading and high noise ...
1
vote
3answers
88 views
Using shielded audio cable for potentiometer sensor
I'm trying to measure a potentiometer from an Arduino's ADC. The potentiometer has a maximum value of 100k ohms and is located about 1 meter from the Arduino. The potentiometer's wiper is wired to the ...
0
votes
1answer
95 views
Bad 100Hz ripple in linear regulator circuit
Background
I'm a beginner trying to make a linear regulator and made some decent progress on a breadboard powering from a 20V laptop charger. After battling off the typical opamp instability issues I ...
3
votes
2answers
85 views
Why isn’t thermal noise work possible?
This must be an absolute naive question, but I’m going to ask it anyway. Aside from the obvious thermodynamic law violation, if I short cut a resistor’s terminals, why doesn’t thermal Nyquist noise in ...
2
votes
2answers
99 views
Reducing noise on a voltage reference
I need a stable, low noise voltage reference that I can adjust between 1.4V and 1.8V. The output should source or sink up to 0.25mA @150Hz max. The output will provide a +1.65V bias for a bipolar ...
2
votes
2answers
109 views
How to amplify a low Amplitude, High frequency signal from Ultrasonic Transducer?
I am working with some ultrasonic transducers, the receiver gets a signal of around 10 mVp-p at 125 kHz and for its purpose needs a gain of around 10.
So far have a simple inverting OP-Amp setup, ...
5
votes
2answers
310 views
How does the differential cap at the input to an ADC/amplifier help reduce noise?
I often see differential amplifiers/ADCs with a conditioning circuit that looks like this:
I'm trying to figure out how Cdiff helps reduce noise/improve things. So far as I can figure out it's ...
0
votes
1answer
67 views
Loudspeaker / Amplifier “POPP” sound [closed]
I have different sound systems here. Some of them share the "problem" that they make a "popp" sound when I switch them on or off using the front-panel switch. If I accidentally switch off the socket ...
0
votes
0answers
40 views
How to do switching noise analysis of dcdc on LTSpice
Background : In one of my board i have used LT8471 as DCDC , as my cards being analog cards, i tried maximum to seperate the power network and analog chain from noise, my initial problems with dc-dc ...
1
vote
2answers
148 views
DC-DC switching converter PCB design
Recently I had a problem with noises in my led driver. I realized that my PCB design was terrible, so I redesigned whole PCB following common rules.
Could you take a look and check if my new design ...
0
votes
2answers
26 views
How to implement sealed line noise-proof method in this circuit?
I am trying to generate -8.5V from my 5V battery. I found a suitable IC for my purposes. The datasheet of the IC (circuit schematic is available below) says
use sealed line noise proof method
(...
0
votes
1answer
20 views
Netfilter (230VAC) without protective earth (PE)
I need to filter my mains input, but I don't have any protective earth (PE). Will a mainsfilter (schaffner for example) still be usefull?
I think so. I think the mains filter despite of not being ...
2
votes
1answer
50 views
Conversion of Additive Noise to Phase Noise
RF Microelectronics by Razavi contains the following snippet in section 8.7.3 concerning the analysis of phase noise in oscillators:
We write \$x(t)=A\cos(\omega_0t)+n(t)\$ where \$n(t)\$ denotes ...
0
votes
4answers
121 views
How do I measure very low frequency noise?
I'd like to measure low-level noise in the 1 Hz to 100 kHz range, for example at the output of a LDO. For higher frequencies a spectrum analyzer would do the job, but most only go down to the MHz ...
1
vote
0answers
44 views
strong noise in microphone unless usb receptacle is grounded
I installed a Banana Pro (like Raspberry Pi), plugged an usb audio stick in, and a microphone in it. I run this thing with a properly dimensioned usb power supply (tried different ones). This way, ...
1
vote
1answer
78 views
How to route a nasty signal (200V/µs)?
I have to route this signal for a distance of ~70mm† through a dense (mostly digital) 2-sided board.
The signal is generated externally and I have no control over its shape, it's basically a pulse ...
1
vote
4answers
113 views
Does reactance increase noise?
Impedance is made of resistance and reactance which is capacitance and inductance. I read that increasing resistance increases noise, but what if capacitance or inductance is increased, does the noise ...
6
votes
2answers
328 views
What's the cheapest way to make a dithered-input ADC?
I know that some of these PICs have ADCs built in, and I may want to use that.
I am wondering if there is a way I can effectively dither the input to a low-bit (like 8 bits) ADC with the fewest parts ...
0
votes
1answer
85 views
Which design to choose for highly stable LED or laser diode driver?
I'm looking at several design choices for driving a LED and/or laser diode in a very stable, low noise way.
The specs are as follows:
current: 1-100mA, adjustable (the adjustment can be either ...
0
votes
1answer
49 views
How to reduce noise in this circuit?
I'm using a Raspberry Pi in a circuit I'm building that includes a few elements.
Elements in the circuit:
PWM driver to control 3 servos
Mic board for recording
Class D Amplifier that drives 2x3W ...
1
vote
2answers
50 views
Phase noise in spectrum analyzers
I'm reading about spectrum analyzers from Keysight's AN 150 and I have two questions regarding phase noise.
The AN states:
No oscillator is perfectly stable. Even though we may not be able to see ...
0
votes
4answers
71 views
Voltage Dividers for a beginner (with respect to soil moisture sensors)
I've just started with electronics and want to make an analogue soil moisture sensor (with Arduino).
When I looked online for an explanation of the working, every site said that it works as a voltage ...
-1
votes
1answer
69 views
Canceling ambient sound [closed]
I've just moved into a new flat and I noticed that there is a lot of car noise coming through windows. I know, I could just close the windows, but that's a less interesting approach to a problem. So ...
0
votes
0answers
64 views
UART noise on A6 GSM module
I'm using the A6 GSM module to send data from my sensors board to a server via GPRS.
The problem is that most of times, usually when the module attaches to the network or connects to the server, ...
1
vote
1answer
62 views
Eleminating radiation from chargers
When I move my EMF radiation meter near a charger it shows me that there is radiation from the charger, and even the device itself radiates when the charger is connected to it.
The chargers emit ...
0
votes
1answer
36 views
Bluetooth audio circuit noise problem
I am working with a bluetooth audio circuit. I am facing noise problems in the mic input so I used B0505S DC DC isolated module. It worked but now when I printed a PCB of the same circuit and I am ...
1
vote
0answers
32 views
Is this SNR change related to aliased common mode noise or some other phenomenon?
Below time series offset value of a force transducer amplifier which is sampled by a 16-bit single ended earth grounded data-acquisition board at 500Hz (red plot) and 12kHz (green plot). Before I was ...
4
votes
2answers
427 views
Why is this the maximum dynamic range in a spectrum analyzer?
In Keysight's popular AN 150 there is a plot of noise and harmonics amplitudes versus the level of the input signal at the mixer (page 57).
It's stated there that the maximum n-th dynamic range is ...
0
votes
1answer
46 views
Effects of increasing current on external noise and SNR for analog transmission
This is a conceptual question about long analog signal transmission exposed to capacitive coupling and EMI noise as shown in below figures:
simulate this circuit – Schematic created using ...
1
vote
0answers
103 views
Where exactly in the environment does the 60Hz power line noise be picked up from?
I am measuring EMG signals using ADS1299, and I have problems removing/eliminating the 60Hz noise in my measurements. I measured the EMG signal in differential mode, and I also incorporated a driven ...
0
votes
0answers
200 views
How to avoid noise in YHDC SCT-013-000 current transformer?
I have a SCT-013-000 current transformer which I have connected to Arduino Uno with a burden resistor of 33 ohms and the calibration value I am using is 60.
The problem is we are getting current ...
0
votes
2answers
73 views
What can be said about the nature of the noise by looking at this spectrum?
I use some industrial amplifier modules where each of them amplifies force transducers. All amplifiers are powered by a single power supply and the output.
Amplifier is set to 6kHz filter. And there ...
1
vote
1answer
72 views
Noise problems in current sensing
I have the following circuit:
simulate this circuit – Schematic created using CircuitLab
I am using a motor from an electric bike, as a generator and I am rotating it using a drill, to test ...
4
votes
0answers
85 views
Induced power supply noise on switch contact
I have a circuit that has a 24V section and a 5V section, separated by opto-isolators and an isolated DCDC converter.
Both sides of the DC-DC have decoupling caps, and the MCU has one per Vcc pin. ...
0
votes
2answers
48 views
Trying to couple some noise
My problem is easy to explain. I want to couple/add some Noise into 240V 50Hz. For this purpose, I have a Noise Generator which is triggered manually with a signal processed by a microcontroller.
I ...
0
votes
1answer
138 views
Electrical noise resets & chattering in relay modules using ESP8266
I am trying to build my own SONOFF like device by using a Wemos D1 mini and associated circuitry. I am facing an issue with electrical noise where whenever switching of the relay causes chattering ...
1
vote
1answer
56 views
Design/Purchase a Filter for Data Acquisition System
We have several types of data acquisition devices where I work. They're used primarily to measure low frequency voltages (<100HZ, +/-10V). One device has a built in filter that does an excellent ...
