Broadband PXI local oscillator modules with low phase noise and fast switching speed

Abstract

This paper presents two local oscillator modules developed for PXI instrumentation. The modules are based on a novel, patented PLL design that combines fast switching speed, low phase noise, and low spurious characteristics. The modules cover 3–10 and 2–20 GHz frequency ranges respectively. The step size is 0.1 Hz for both modules. The measured phase noise at 10 kHz offset is about −121 dBc/Hz at 10 GHz and −115 dBc/Hz at 20 GHz respectively. The switching time is less than 500 microseconds to be within °50 kHz from the final frequency for any frequency step within the entire operating range. Spurs do not exceed the −70 dBc level. Both developed modules occupy two standard 3-U PXI slots and can be used in a variety of synthetic instruments based on the PXI platform.