The effects of small contaminating signals in nonlinear elements used in frequency synthesis and conversion

Many electronic systems use nonlinear elements to add or subtract two frequencies or to multiply or divide a frequency by an integer. Some level of contamination by small undesired signals is always present and the ability to predict the effects produced by their passage through the nonlinear elements is important in analyzing system performance. These effects can often be predicted, for frequency mixing (addition and subtraction), multiplication and division, by decomposition of the contaminating signal into equivalent AM and FM sidebands whose effects are more easily estimated. One important effect that occurs in frequency division is a sampling process which translates the frequencies of the interfering signals. A method for predicting these effects is explained and experimental results, demonstrating the application and applicability of the method, are reported.