Noise Factor
Abstract
The receiver noise factor (noise figure) is the ratio of input signal-to-noise power ratio at the antenna terminals to the signal-to-noise power ratio at the output terminals of the receiver, when the input termination is at room temperature (290K). The average noise factor over the frequency range of interest for the particular case of AM and FM surveillance receivers is a measure of the amount of noise power added to a signal by the receiver, thereby degrading signal quality. The noise factor is usually expressed in decibels, it is commonly referred to as the noise figure. Five methods of measurement are given, and the method used will depend upon the test equipment available, the desired accuracy, and the time available to devote to the measurement. Noise figure is usually measured only for the linear parts of the receiver that precede the demodulator. For CW and AM receivers, this includes the RF and IF stages up to the second detector. For FM receiver this includes the RF and IF stages up to the first limiter stage. For receivers with a linear demodulator, such as a product detector, noise figure may be measured for the entire receiver from the antenna input terminals to the audio output terminals.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 02, 1983
- Accession Number
- ADA124797
Entities
Organizations
- United States Army Test and Evaluation Command