A doubling mixer includes an input tuned circuit adjusted to the frequency of an input signal, an output tuned circuit tuned to the desired output frequency, and a local oscillator. Semiconductor switch means are interposed between said input and output tuned circuits, the switch means being responsive to the local oscillator to conduct twice during each cycle thereof. The relationship between the input and output signal frequencies as a function of the local oscillator frequency may be expressed as:F.sub.IF = F.sub.S .+-. 2 F.sub.LO