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The noise figure is the difference in decibel (dB) between the noise output of the actual receiver to the noise output of an "ideal" receiver with the same overall gain and bandwidth when the receivers are connected to matched sources at the standard noise temperature T 0 (usually 290 K).
F quantifies how much the signal degrades with respect to the noise because of the presence of a noisy network. A noiseless amplifier has a noise factor F = 1, so the noise figure for that amplifier is NF = 0 dB: a noiseless amplifier does not degrade the signal to noise ratio as both signal and noise propagate through the network.
A noise-figure meter could automate that procedure as follows: A gated broadband noise source (such as an avalanche diode) drives the device under test. A measurement is made with the noise source on; another measurement with the noise source off. From those measurements and the characteristics of the noise source, the noise figure can be ...
If the noise has expected value of zero, as is common, the denominator is its variance, the square of its standard deviation σ N. The signal and the noise must be measured the same way, for example as voltages across the same impedance. Their root mean squares can alternatively be used according to:
Noise reduction, the recovery of the original signal from the noise-corrupted one, is a very common goal in the design of signal processing systems, especially filters. The mathematical limits for noise removal are set by information theory .
An important consequence of this formula is that the overall noise figure of a radio receiver is primarily established by the noise figure of its first amplifying stage. Subsequent stages have a diminishing effect on signal-to-noise ratio. For this reason, the first stage amplifier in a receiver is often called the low-noise amplifier (LNA ...
In 2022, locals called police about 5,500 times because of noise in their neighborhoods. That's one call every 95 minutes, and at least 15 calls a day.
This is a measure of how much noise is introduced in the amplification process. Noise is an undesirable but inevitable product of the electronic devices and components; also, much noise results from intentional economies of manufacture and design time. The metric for noise performance of a circuit is noise figure or noise factor. Noise figure ...