Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [signal-to-noise]

144 questions
15
votes
3 answers

Is it sensible to always use larger diameter conductors for carrying smaller signals?

This question as originally written sounds a little bit insane: it was originally asked to me by a colleague as a joke. I am an experimental NMR physicist. I frequently want to perform physical experiments which ultimately boil down to measuring…
Landak
  • 655
  • 7
  • 17
13
votes
9 answers

Why Decibels are used to measure Signal to Noise Ratio?

We just started a communications course in college and we came across SN ratio. The following is an ambiguity I am facing which my professor is unable to resolve: Signal to Noise Ratio is the ratio of signal power to the noise power. It is often…
iluvthee07
  • 301
  • 2
  • 5
  • 12
13
votes
7 answers

Amplifying a nV signal across a small resistance

I am interested in the feasibility of amplifying/measuring a nV level (or otherwise assumed very small) signal across a small resistance. The SNR of this signal isn't so bad in itself because of the very small thermal noise, due to the small value…
Orhym
  • 241
  • 1
  • 9
8
votes
7 answers

Why is one return conductor for each forward conductor in a ribbon cable better than a shared return conductor?

I don't understand why second way of implementing is better than the first one? I have my own basic logic regarding this topic, but i am not confident if what i think is correct! so i was looking forward to have some general view on this topic!
Hilton Khadka
  • 811
  • 1
  • 13
  • 29
7
votes
3 answers

Attenuator noise figure and loss

My question is with regard to how attenuators effect noise. From what I understand $$ \text{NF} = 10\log \left( \frac{S_{in}/N_{in}}{S_{out}/N_{out}} \right) = 10\log \left( L \frac{N_{out}}{N_{in}} \right) = L_{dB} +…
user968243
  • 1,323
  • 7
  • 18
  • 32
6
votes
5 answers

Does "a signal is buried in noise" mean that the noise amplitude is still smaller than the signal amplitude? (Special case: Lock-in amplification)

I heard that Lock-in amplifiers (LIAs) especially play to their strengths when the signals are weak compared to the noise level. But then I talked with someone about it, who understands the principles of lock-in amplification, and she said - which…
AskingBecauseIHaveQuestions
  • 79
  • 7
6
votes
2 answers

False Positives on Arduino Input

I've used analog and digital input for a multitude of applications with the Arduino Uno board. It has continuously given extremely non reliable readings, where the analog input is always fluctuating, or digital read will read true even if it isn't…
Mark Y.
  • 119
  • 2
  • 7
6
votes
1 answer

Charge, Voltage, or Current? What can be measured with the highest SNR?

Suppose I have a Faraday cup and a certain number of ions hit the detector. What is the highest signal to noise ratio way / circuit to measure this... does one measure the charge (coulombmeter), voltage (voltmeter), or current (ammeter)? Is there…
seven68
  • 93
  • 1
  • 1
  • 7
6
votes
5 answers

Detection of signals buried in noise

This is more of a general question to see which methods are the most common to improve the detection of a signal which is buried in noise. Currently, we are building an optical system for medical imaging and the signal that is being detected is…
James
  • 113
  • 1
  • 9
6
votes
2 answers

How to amplify a tiny signal riding on a large common mode square wave

I have a small signal of about 10uV-100uV riding on about 1V common mode. I have tried to depict this in the picture. I am interested in designing a board level circuit(cannot use a commercial lock-in amp) that can amplify the 10uV-100uV signal to…
user1155386
  • 287
  • 1
  • 2
  • 7
6
votes
2 answers

Inferring DC performance from a Sigma Delta ADC datasheet noise floor figures

So ive been playing with some Sigma Delta ADCs, for sampling low frequency (<2Khz) AC signals. The ADC supports a differential input with a full scale value of about +-500mV at its inputs. I have constructed a reference design which consists of an…
MAM
  • 1,801
  • 13
  • 24
6
votes
1 answer

Trifilar Transformer Common-Mode Rejection Circuit (Signal Recovery, Hybrid Combiner, RF)

I'm trying to develop a circuit that allows me to effectively subtract two different sources of RF noise from a single signal at the same time. I am planning to use something called a "trifilar" transformer, which is effectively a transformer with…
iwantmyphd
  • 417
  • 1
  • 5
  • 17
5
votes
4 answers

How to select gain for an amplifier before ADC?

The circuit has been simplified as shown in the picture. Signal source is connected with an analog amplifier, which amplifies the ac signal and also raise it by 1.5V to match with the range of the 0-3V ADC. Some characteristics of the…
richieqianle
  • 1,612
  • 3
  • 24
  • 44
4
votes
1 answer

How to extract ENOB from LTSpice simulation and see the effects of oversampling?

I have a fully differential instrumentation amplifier circuit with a gain of 536 to map a 3mVpp signal (centred around 1.65V) to +/-1.6V, as shown here. My signal bandwidth is 250Hz, and I would like to use a 12bit differential ADC (stm32g491) with…
davidanderle
  • 135
  • 6
4
votes
1 answer

How is noise reduced using a sigma-delta converter?

Perhaps I'm sleepy but I can't quite get my head around how a sigma delta converter takes the noise that is in a bandwidth of (X) Hz and by over sampling spread, that same amount of noise over 2(X)Hz. My understanding is that basically we're doing…
Chef Flambe
  • 1,011
  • 11
  • 22
1
2 3
…
9 10