A frequency generator produces two widely spaced frequency outputs at the terminals of a single transistor. There is also disclosed a fixed frequency dual downconversion receiver, comprising: an analog first downconversion and IF filter stage; means for one-bit coding of the downconverted signal; and means for second downconversion by digital subsampling. The receiver is particularly suitable for use in GPS appliocations, and the frequency generator can advantageously be used to produce the local oscillator signal for the first mixer, and a clock signal for the digital subsampler.