Measurement

Y-Factor

A noise measurement technique that determines noise figure by comparing the output noise power of a device with a calibrated hot (noise source ON) and cold (noise source OFF) input

Category: Measurement

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Understanding Y-Factor

The Y-factor is the ratio of output noise power with the noise source on (hot) to the output noise power with the noise source off (cold): Y = N_hot / N_cold. From this ratio and the known ENR (Excess Noise Ratio) of the noise source, the noise figure is calculated.

NF = ENR / (Y-1) in linear terms, or NF(dB) = ENR(dB) - 10*log10(Y-1). This method is the standard technique for measuring noise figure of amplifiers, mixers, and receivers using a noise figure meter or analyzer.

Common Questions

Frequently Asked Questions

What equipment is needed for Y-factor measurement?

A calibrated noise source with known ENR, a noise figure analyzer or spectrum analyzer, and appropriate cables and adapters for the frequency range.

What are sources of error in Y-factor measurements?

Noise source ENR calibration accuracy, mismatch between components, instrument noise floor, and temperature variations are the primary error sources.

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