Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [snr]

Signal-to-Noise Ratio

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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
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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 object being measured. Noise determines environment…
Kentzo
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How does a preamplifier improve the Signal-to-Noise Ratio (SNR)?

I'm trying to understand how a preamplifier works. Is the noise not amplified the same amount as the signal? If so, how is that done in the preamplifier?
physicsnoob1000
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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
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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
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Which noise sources dominate in a receiver?

For a radio receiver that digitizes over-the-air RF signals (such as an SDR), my assumption (as a DSP guy; pardon my hardware ignorance!) has been that thermal noise dominates total receiver noise, and quantization noise is a slightly distant…
Gillespie
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Why have a filter before the LNA in LoRa boards?

I've looked through some Semtech reference board schematics and found one strange thing: they put SAW filters both before and after the LNA. For example here is part from a Semtech reference board electrical schematic (1 and 2.) The same thing from…
lazba
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The relationship between bit depth and SNR in ADC

An 8-bit audio signal has a theoretical maximum SNR of 48.16 dB (20log(2^8)). My question then would be, does this work in reverse, i.e. would an analogue audio (or video) signal with an SNR of <=48 dB only be worth sampling at 8 bits? Or is this…
pvmnerd999
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How to set up an experiement to measure SNR for an EEG amplifier?

I have built an EEG amplifier with gain of 2000 and bandwith at 1~40Hz. I use an Instrument Amplifier for pre-Amp and a non-inverting opamp as post-amp and finally bandlimit at 40Hz using a 4th-order LPF. I would like to measure the SNR for my EEG…
jhyap
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DVB reception: Why do I need to add a coaxial cable to my installation to improve SNR of the signal?

I have the following installation: Dipole antenna <------> Coaxial cable (3 m) <-----> DVB receiver If I connect my dipole antenna directly to the DVB receiver, removing the coaxial cable (the cable of the antenna is long enough), the signal has…
Mathieu Tournier
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Safe to connect SDR to home Cable?

I have an SDR (RTL2832u) that connects to an antenna and can receive over the air just fine. I'm wondering if the signal of a home cable connection would be too strong to connect to the SDR input or is it safe? Say for example my home cable modem…
Brad Hein
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How to measure SNR with an oscilloscope

Suppose I have a signal that consists of a sine plus noise. Is it possible to measure the SNR with an oscilloscope? Is the following procedure correct? Check the noise floor in the FFT mode of the oscilloscope (green FFT in picture). Connect the…
user171780
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how to calculate the signal-to-noise ratio from a transient

This is probably a dumb question about the signal-to-noise ratio (SNR). I know the SNR of a signal is defined as the signal power divided by the noise power. Now I have a noisy transient voltage decay V=V(t), and the voltage decays toward zero as…
shva
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To find theRMS noise voltage in a circuit, can the measured RMS voltage be subtracted from the RMS voltage of shorted probes?

I'm trying to estimate the SNR of a circuit, which includes measuring the noise power of an analog trace. Right now, I'm attempting to measure the noise with a high bandwidth scope probe, ac coupled, low inductance ground leads, with 1x attenuation.…
powerboi95
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How to find the source of a noise in a particular band

The problem: The ADSL2+ service at home is not performing up to its potential. The modem is supposed to sync at 16 Mbps (downstream) but the it does only up to 11.5 Mbps. Using the diagnostic tools provided by the modem, I figured out there's noise…
alokoko
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