11. Mixer circuits are characterized by their properties such as conversion gain ( or loss ), and noise figure . 12. The low-noise quality of an LNB is expressed as the noise figure ( or sometimes noise temperature ). 13. The noise figure of a valve is inversely proportional to its transconductance; higher transconductance generally means lower noise figure. 14. The noise figure of a valve is inversely proportional to its transconductance; higher transconductance generally means lower noise figure . 15. Noise figure is not usually an issue for power amplifier valves, however, in receivers using valves it can be important.16. An equivalent definition is : noise figure is the factor by which insertion of the amplifier degrades the signal to noise ratio. 17. Some commercial microwave noise generators use avalanche diodes to create a large excess noise figure that can be turned off and on. 18. Noise figure in an ideal DFA is 3 dB, while practical amplifiers can have noise figure as large as 6 8 dB.19. Noise figure in an ideal DFA is 3 dB, while practical amplifiers can have noise figure as large as 6 8 dB. 20. Noise figure is a measure of the noise produced by a receiver compared to an ideal receiver, and this needs to be minimized.
