[MPATT AND GUNN PUMP SOURCE NOISE IN PARAMETERIC AMPLIFIERS

Abstract

In this thesis the effect of pump source noise on the noise figures of parameterie atiplifier has been stdied by deriving a mathematical relation governing this noise figure. The pump sources used are the ThPATT diode or Gunn diode. It is also shown that the noise genated in Ii1PATT diode or the transferred Electron device modulates the output of the pump source in which one of them is used. It is found that the noise in the output of the paramp due to noisy pump source is centered at the pump frequency, idler frequccy, twice the pump frequency sum of pump and signal frequencies, cum and difference of twice the pump frequencies and signal frequencies. iith the use of a suitable filter, all other not components can be filtered out,except the noise centered at pump frequency and idler frequency. These noise components are transferred to that at signal frequency thich is the frequency of the output of parameteric amplifier. Noise figure is found to increase due to the noisy pump source. it is further shown that this increase in the noise figure of the paramp is more in case a strong signal source is used.