Three tone meassurement

can any help me to find out exact method of two-tone / Three-tone measurement of RF circuit. if my circuit (rectifier) is working at three band of frequency (900 MHz, 2100 MHZ and 3.5 GHz) then how i will measure output voltage using three tone method?

Thanx in advance .....

http://www.keysight.com/upload/cmc_u...?&cc=RO&lc=eng
https://cdn.rohde-schwarz.com/pws/dl...9/1EF79_1E.pdf