So if two sine wave signals at frequencies and are applied to a linear device, the output is simply the sum of the outputs when the two signals are applied separately with no product terms. Thus, the function must be nonlinear to create mixer products. A perfect multiplier only produces mixer products at the sum and difference frequencies , but more general nonlinear functions produce higher order mixer products: for integers and . Some mixer designs, such as double-balanced mixers, suppress some high order undesired products, while other designs, such as harmonic mixers exploit high order differences.
So if two sine wave signals at frequencies and are applied to a linear device, the ,output is simply the sum of the outputs when the two signals are applied separately with no product terms. Thus, the function must be nonlinear to create mixer products. A perfect multiplier only produc,es mixer products at the sum and difference frequencies , but more general nonlinear functions produce higher order mixer products: for integers and . Some mixer designs such as double-balanced mixers, suppress some high order undesired products while other designs, such as harmonic mixers exploit high order differences.