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The noise factor is thus the ratio of actual output noise to that which would remain if the device itself did not introduce noise, which is equivalent to the ratio of input SNR to output SNR. The noise factor and noise figure are related, with the former being a unitless ratio and the latter being the logarithm of the noise factor, expressed in ...
Noise figure (NF) is noise factor (F) expressed in decibels. F is the ratio of the input signal-to-noise ratio (SNR i) to the output signal-to-noise ratio (SNR o). F quantifies how much the signal degrades with respect to the noise because of the presence of a noisy network.
Signal to noise ratio may be abbreviated as SNR and less commonly as S/N. PSNR stands for peak signal-to-noise ratio. GSNR stands for geometric signal-to-noise ratio. [13] SINR is the signal-to-interference-plus-noise ratio.
Friis formula or Friis's formula (sometimes Friis' formula), named after Danish-American electrical engineer Harald T. Friis, is either of two formulas used in telecommunications engineering to calculate the signal-to-noise ratio of a multistage amplifier. One relates to noise factor while the other relates to noise temperature.
An attenuator is a passive broadband electronic device that reduces the power of a signal without appreciably distorting its waveform. An attenuator is effectively the opposite of an amplifier, though the two work by different methods. While an amplifier provides gain, an attenuator provides loss, or gain less than unity. An attenuator is often ...
The required sound attenuator insertion loss is the difference between the calculated path and the target background noise level. [16] If no attenuator selection is feasible, the noise control engineer and mechanical must re-evaluate the path between the equipment and the sound attenuator.
Some commercial microwave noise generators use avalanche diodes to create a large excess noise figure that can be turned off and on. The impedance of the diode is different during the two states, so an output attenuator is used. The attenuator reduces the noise source output, but it minimizes mismatch loss. (Swain & Cox 1983, p. 26).
The noise factor (a linear term) is more often expressed as the noise figure (in decibels) using the conversion: = The noise figure can also be seen as the decrease in signal-to-noise ratio (SNR) caused by passing a signal through a system if the original signal had a noise temperature of 290 K. This is a common way of expressing the noise ...