APPENDIX A: 



DESCRIPTION OF THE PDA AND ITS OPERATION 



The PDA was designed primarily for the determination 

 of the probability density (PD) of random noise. Approxi- 

 mations of the PD curves of other waveforms, such as sine 

 waves, square waves, and others can also be obtained. 

 The PD of a sine wave and square wave as obtained with the 

 PDA are shown in figure Al. Also shown are the theoretical 

 PD's of the two curves. 



3.0- 



SQUARE 

 WAVE 



•THEORETICAL 

 CURVE 



-1 



1 -2-10 



AMPLITUDE IN STANDARD DEVIATION UNITS 



Figure Al. Theoretical and experimental 

 probabi 1 ity density curves of the square wave 

 and the sine wave. 



41 



