Low signal to noise ratio frequency synthesiser - has IF lying in frequency band specified by auxiliary signal

摘要

The frequency synthesiser contains a normal frequency generator (G) with a harmonic generator (V) (non-linear circuit). - The generator output is mixed in a first mixer with an auxiliary signal (H). The result is then mixed with the output of an interpolation oscillator (I'). The doubly mixed signal is finally mixed with the auxiliary signal again. The three mixers are separated from one another by BP filters and from the input and output of the mixing chain by LP filters. - The IF signal obtained by filtering the output of the first mixer (M1') lies roughly in the centre of the auxiliary signal adjustable frequency range in order to reduce the signal to noise ratio.