Agilent 1958-01 free download

File name 1958-01.pdf

HEWLETT- PACKARD JOURNAL TECHNICAL INFORMATION FROM THE -hp- LABORATORIES Vol. 9 No. 5 JBLISHED BY THE HEWLETT-PACKARD COMPANY, 275 PAGE MILL ROAD, PALO ALTO, CALIFORNIA JAN., 1958 An Automatic Noise Figure Meter For Improving Microwave Device Performance BECAUSE it compares actual output noise ment, a noise figure meter has been developed power with the output noise power of a which both measures noise figure automati theoretically ideal device, the quantity noise cally and has a number of important conven figure is generally used to specify in a funda iences not previously available. The meter can mental manner the quality of amplification be used with either 30- or 60-megacycle i-f re SEE ALSO: provided in micro ceivers and has a primary measuring range "Noise figure and wave devices such as from 3 to 30 db. its measurement," r e c pe 3 i v e r s , f o r w a r d - . The instrument is designed to operate with wave and backward-wave tubes, etc. In addi gas discharge noise sources for measurements tion to being a fundamental property, how on microwave devices and with temperature- ever, noise figure can also be much faster and limited diodes for measurements on i-f ampli easier to measure than equivalent measure fiers. A diode source and a series of high-per ments with signal generators. From a perform formance waveguide noise sources have been ance standpoint, improving receiver noise fig developed for these purposes. Supply voltages ure in a system such as a radar is just as valuable for the sources are provided by the instrument. and tremendously more economical than in The instrument provides two additional out creasing transmitter power an equivalent puts for simplifying various measurements. amount. A 5 db improvement in receiver noise One of these is a voltage that increases with the figure, for example, is equivalent to increasing gain of the device being measured and is thus transmitter power by 3:1. valuable in such work as adjusting twt's t