The APSINXXG is a series of low-noise and fast-switching microwave signal generators covering a continuous frequency range from as low as 100 kHz up to 12, 20, and 26 GHz, respectively, with a 0.001 Hz resolution. The APSINXXG provide an accurately levelled output power range and high spurious suppression. Advanced frequency synthesis with fractional-N divider makes for low SSB phase noise and micro-Hz resolution.