Frequency conversion with positive nonlinear resistors

A nonlinear r esistor subject to an almost periodic voltage will absorb power at some frequencies, a nd supply power at other frequencies. Necessary and s ufficien t relations a mon g these powers are found. Among the practical conseq uences are t he resul ts: (1) modulation efficiency cannot exceed unity, (2) subharmonics are not produced , and (3) the effici cncy of generating an nth harmonic cannot exceed 1/n2 .