The SNR of a Frequency Doubler

The output signal-to-noise ratio (SNR) of a frequency doubler is calculated using the transform method for nonlinear systems with stochastic inputs. The class of nonlinearities considered is the even
V
th-power-law devices. It is found that the squarer (
V = 2
) is optimum at low SNR, while for high SNR,
V rightarrow 0
is best. Choice of the bandpass filters in the system is also considered.