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Questions tagged [signal-to-noise]

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5 votes
2 answers
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Does antenna arraying for deep space communications affect the CMB contribution?

My question pertains to the reduction in SNR achieved by arraying parabolic antennas in deep space communications. My engineering education is a bit out of date, so my thanks for your patience. I ...
Larry Gilman's user avatar
0 votes
0 answers
41 views

Achieved SNR is different than the simulation results

I have designed a transimpedance amplifier as follows: Based on the simulation, I should get around 58 dB for SNR @3MHz: But what I achieved in my experimental results is as follows: Supply voltage ...
Andromeda's user avatar
  • 477
-1 votes
2 answers
46 views

SNR calculation

I want to calculate the SNR of the following signal (the blue signal): The signal peak value is: 0.0292 V The noise peak value is: 0.0012 V Based on the following formula: SNR=20 log(Vp-Signal/Vp-...
Andromeda's user avatar
  • 477
0 votes
0 answers
26 views

Optimal gain for RF pulse detection in RTLSDR

I'm trying to optimize the SNR of low-power RF pulses (from wildlife telemetry tags @166Mhz, unmodulated, a few DBs above noise floor) as they go into an RTLSDR. The detection performs windowed FFTs ...
TvE's user avatar
  • 286
1 vote
1 answer
49 views

Calculate noise figure for LNA + SAW + RTLSDR

I'm trying to optimize the SNR of low-power RF pulses (from wildlife telemetry tags @166Mhz, unmodulated, a few DBs above noise floor) as they go into an RTLSDR. I have a number of questions about how ...
TvE's user avatar
  • 286
0 votes
2 answers
55 views

Plotting signal to noise ration (SNR) in SPICE softwares

I want to plot SNR in TINA TI software, do you have an idea how can I plot do it? In this software I just have access to total noise plot and data as follows: (what would be the relationship between ...
Andromeda's user avatar
  • 477
1 vote
2 answers
145 views

Twisted pair wiring 4-20 mA sensor

I have a pressure sensor with 24 V, GND and 4-20 mA signal output pins. It will communicate with a PLC. I will only use 3m of wire max. for each pin. The installation will be on the rooftop maybe a ...
Gurul_01's user avatar
0 votes
0 answers
66 views

NF (Noise Figure) calculation - task

In a 622 Mbps radio-link interface, it was assumed that the BER would be 10^-10 when the signal-to-noise ratio at the receiver point is 7.8 dB, while its sensitivity for a fixed modulation-code scheme ...
airborne's user avatar
1 vote
1 answer
106 views

Simulate different grounds with noise in LTSpice?

Is there any way to split 2 different grounds in LTSpice? What my aim is to observe the optocoupler input side called "GND-D" and collector output side that called "GND-A"; I want ...
Andy Chen's user avatar
3 votes
2 answers
1k views

How did old mobile phones amplify signals lower than the noise floor?

In the early days of GSM in around 2000 when the network was still not fully deployed, it was common for me to receive very low signal, even sometimes No Signal due to out of network. I used to use a ...
AirCraft Lover's user avatar
0 votes
3 answers
153 views

How can I determine the dimensions of a spiral trace on a PCB?

I was designing a circuit that contains some analog signals along with signals of relatively low frequency (2.5 kHz) and I was reading a bit about norms, standards, and good practices for the design ...
WalterPH's user avatar
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4 votes
1 answer
395 views

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 ...
davidanderle's user avatar
1 vote
0 answers
67 views

Averaging time, T, of analog lock-in amp equivalent in digital lock-in amplifier

My understanding of lock-in used to be only that of an analog lock-in amplifier. Now, I am thinking about digital lock-in technique. Reading this has been helpful. However, I am having trouble ...
Blackwidow's user avatar
3 votes
1 answer
593 views

Step by step calculation of noise factor does not match the overall system calculation

I know this is a very stupid question but I've been trying for a couple of days now to figure out what mistake I'm doing. I have two cascaded blocks as following: Block one is an amplifier with: Gain (...
Ahmad KFUPM's user avatar
0 votes
3 answers
165 views

Best way to transfer indication signal from one STM32 to another STM32 [closed]

This is the system: I need a simple way to pass a signal from the upper controller to the lower controller. The whole purpose is to read an analog voltage, sample it, make statistics, and transfer to ...
Knowledge's user avatar
  • 441
1 vote
2 answers
244 views

Derivation of attenuator noise factor as a function of its physical temperature

I have been struggling for the past few days with the noise analysis of an attenuator of attenuation \$l\$, at a temperature \$T_A\$, connected to a source with input noise temperature \$T_0\neq T_A\$....
CZa's user avatar
  • 11
3 votes
1 answer
415 views

How to eliminate the noise of this circuit?

I've built the following circuit on a PCB with reference to a TI's solution. I changed the gain of the INA to 10 and the gain of the A3 stage to 40. I also changed the cut-off frequency of the A4 ...
Jack Black's user avatar
0 votes
1 answer
221 views

Does placing two optocoupler one below another in PCB design affect any signal?

I am working on a circuit where I am using multiple ultrasonic sensors which work on 24V, to read the sensor output through a microcontroller that accepts 5V. I am using optocoupler PC817 to maintain ...
user274774's user avatar
0 votes
0 answers
38 views

RF channel noise interference calculation

I am trying to calculate how far a co-channel or noise source has to be from the primary channel, in this case a WiFi channel, for it not to interfere with the link performance. This question takes ...
Linkyyy's user avatar
  • 1,203
1 vote
0 answers
84 views

How to determine noise power and SNR from extinction ratio?

I have a pulse train signal with infinite extinction ratio (ER). I want to add a white gaussian noise to my signal to get ER=15 (dB). I know that ER=P1/P0, i.e., the power level with the light source ...
Amy 's user avatar
  • 11
0 votes
2 answers
106 views

ATmega analog comparator generates spurious interrupts

I'm experimenting with the comparator inside a ATmega328 to see if it can be used for zero detection of a DC 2.5V superimposed AC signal monitored on one of the ADC inputs. I use the code as shown ...
wogoos's user avatar
  • 71
2 votes
1 answer
777 views

Potentiometer ADC noise varies based on position of wiper?

I have a potentiometer setup as a voltage divider like so, where the wiper of the potentiometer gets fed into my MCUs ADC Pin: When I measure the noise of the incoming ADC signal, I get different ...
scottc11's user avatar
  • 433
0 votes
0 answers
96 views

Acceptable SNR for a Sound Level Meter

I'm designing a low power (<150mW) sound level meter (SLM) using a 24bit ADC (preliminarily using the LTC2512-24). This is for audible frequency range signals only (20Hz - 20kHz). I'm focused on ...
davegravy's user avatar
  • 439
0 votes
1 answer
213 views

Can an LNA noise figure be normalized to dBm to estimate the minimum detectable signal?

If a device claims a noise figure of 0.3 dB NF such as the Qorvo QPL9547, can you calculate the dBm value of a signal that is at the noise floor (ie, a barely detectable signal)? Otherwise stated: I ...
KJ7LNW's user avatar
  • 2,022
0 votes
1 answer
1k views

Signal to Noise Ratio Vs Signal to Distortion Ratio

I am a bit new to this field and I was reviewing some speech enhancement papers. These two terms keep popping up every once in a while so I was very confused as to what the difference between these ...
user297016's user avatar
1 vote
1 answer
733 views

Estimating shot noise - what's the origin?

If I have some photon detector, say a CCD, how do I estimate the error introduced by shot noise correctly? Typically, sources found on the internet say that the shot noise is the square root of the ...
hintze's user avatar
  • 121
1 vote
0 answers
182 views

Consider Noise in Link Budgets

I want to verify the range of my RF-system for a university project. I use two transceivers (Datasheet) and one power amplifier on the transmit side (Datasheet). The target range is 120 km over which ...
PlzBePython's user avatar
0 votes
1 answer
2k views

Noise Figure of an Attenuator

it is known that the noise figure of an attenuator is equal to its attenuation coefficient L. A proof of this statement is provided here. Basically, it uses the formula (Reference): $$F = 1 + \frac{...
Kinka-Byo's user avatar
  • 3,540
0 votes
4 answers
1k views

Build a Radiated EMI Generator

I'm building a radiated noise generator. My intention is to expose my developed equipment to electromagnetic noise. I want to check the behavior of the equipment in noisy situations. So I want to ...
Cristian Pastro's user avatar
0 votes
1 answer
277 views

Can I connect GNDD with GND to get stable result?

I am using JY-S60 Signal conditioner (SC) (click here to see datasheet, giving amazon link, could not find specific link for datasheet) with small load cell click to see load cell datasheet. I have ...
nyeas001's user avatar
2 votes
2 answers
592 views

Amplitude Spectral Density from a Fast Fourier Transformation

I want to calculate the Noise-equivalent Power (NEP) of a photodetector. Hereto, I have to measure the Amplitude Spectral Density (ASD) of the detector and divide the result by the Responsivity: The ...
Alberto's user avatar
  • 23
0 votes
0 answers
66 views

S/N ratio or distortion analyzer

I'm having trouble finding an affordable low bandwidth analyzer solution for measuring audio spectrum performance (20KHz and below). Does anyone have a suggestion for buying (new / used) or building ...
Mitchell's user avatar
1 vote
1 answer
1k views

Noise figure calculation in LTspice

I am a newbie in LTspice so the question can be seemed to be bit stupid, but I have build an LNA and now I want to calculate the noise figure of the system. I have run the .noise statement to ...
Abhishek Chakraborty's user avatar
0 votes
1 answer
4k views

What is the derivation of the Shannon-Hartley theorem? [closed]

I know by Hartley's theorem that information is proportional to bandwidth and time. The capacity corresponds to information and bandwidth is there. I don't get how the logarithmic part corresponds to ...
AndroidV11's user avatar
1 vote
2 answers
708 views

In noise voltage equivalent circuit, why are the source and load resistances equal?

Yes I am aware of the maximum power transfer theorem. I don't get though what the lesson meant, especially by worst condition.
AndroidV11's user avatar
4 votes
2 answers
171 views

Signal averaging CCD

I'm thinking about signal to noise ratio of CCDs and I hope this is the right location to post my question. The Hamamatsu Learning Center seems to be a good starting point to learn about CCDs. I ...
Deglupta's user avatar
1 vote
1 answer
299 views

Noise equivalent power of thermopile sensor?

I am working on the characterisation of thermopile sensor and stuck in determining the NEP of the sensor. My thermopile sensor with AD8630 amplifier receives IR radiation coming from the blackbody at ...
Pukhtun's user avatar
  • 11
0 votes
1 answer
2k views

How exactly does the low-pass filtering in a lock-in amplifier correspond to a time-averaging?

In this white paper of Zurich instruments two ways of explaining a lock-in amplifier are shown: low-pass filtering and time-averaging. Whereas the explanation with time-averaging can easily be done ...
AskingBecauseIHaveQuestions's user avatar
0 votes
1 answer
48 views

Advice on Noise in Square Input Signal

I am reading the following signal from an open drain output, and trying to read the signal frequency. However, I am getting short spikes in the wave as seen below, and this is messing with the reading ...
Mateo Segura's user avatar
0 votes
0 answers
30 views

Maximizing signal to noise ratio for very small radiation detector

I have a very small radiation detector that outputs signal of small amplitude. Requires preamplification before going to an actual amplifier. When constructing the system prior to the preamp, would I ...
Jake's user avatar
  • 9
6 votes
5 answers
2k views

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 ...
AskingBecauseIHaveQuestions's user avatar
2 votes
2 answers
389 views

Producing simulated thermal noise

I’m trying to simulate thermal (Johnson) noise. As I understand it, thermal noise follows a Gaussian distribution, power at the receiver is given by: $$ P = 4kTB $$ And the RMS voltage is given by: $$ ...
PerplexedDimension's user avatar
0 votes
2 answers
291 views

How to calculate noise voltage after amplification?

I'm simulating the thermal noise experienced by some instrument, outputted as a voltage vs time plot. To calculate the "power" of this noise, I'm using: P = 4kTB (k = Boltzmann's constant, T ...
K_M's user avatar
  • 109
0 votes
1 answer
545 views

How to calculate thermal noise contributed by an LNA?

I've written a thermal noise simulation for a piece of equipment which produces the oscilloscope trace one would expect to see coming out of the instrument. Now, I'd like to take into consideration ...
PerplexedDimension's user avatar
0 votes
2 answers
563 views

How to plot thermal noise in the time domain?

The power of this thermal noise is given by: P = 4kT (k = Boltzmann’s constant, T = temperature (Kelvins)) And, thus, the voltage by: V^2 / R = 4kT (R = resistance) Finally, we must take into account ...
PerplexedDimension's user avatar
1 vote
3 answers
159 views

Do parallel LNAs at 90-degrees to eachother reduce the noise floor more than side-by-side?

Wiring amplifiers in parallel in a summing configuration improves the signal to noise ratio because amplifier noise in each LNA is uncorrulated. However, external noise sources will still be a factor ...
KJ7LNW's user avatar
  • 2,022
0 votes
1 answer
431 views

How does wiring two LNAs in parallel affect charactaristic impedance?

It appears that wiring amplifiers in parallel improves the signal to noise ratio. I thought I would experiment with two SAV-541+ LNAs in parallel and see how they perform: How does wiring an LNA in ...
KJ7LNW's user avatar
  • 2,022
6 votes
1 answer
266 views

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), ...
seven68's user avatar
  • 103
0 votes
3 answers
320 views

Signal to noise in relationship with limit of detection and/or signal strength

I wonder about the following: The limit of detection is given as being 3 sigma of the blank peak away from the blank signal (which is noise finally, I think?). What struggles me is: In my head this is ...
Ben's user avatar
  • 625
1 vote
0 answers
47 views

Regarding signal to noise ratio

I had set up multiple receivers and I was recording the same signal on all of them. I then stacked all of these signals. I have read that to improve the signal to noise ratio, mean and median of this ...
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