High bandwidth RF signal generators that cover frequencies over 6 GHz are expensive pieces of test equipment that are usually the domain of large corporations and research labs. An open source, crowd-funded project —now available on Crowd Supply— aims to shatter the cost barriers and make multi-GHz RF signal synthesis accessible to everyone.
ERASynth —unlike many competitors— does not rely on a single fractional PLL, instead it uses a multi-loop PLL architecture to provide continuous frequency coverage from 250 kHz to 15 GHz in 1 Hz steps. Single loop fractional PLLs with integrated VCOs are great for generating RF signals with fine frequency resolution, but they are plagued by elevated phase noise floors and excessive spurious artifacts.
ERASynth improves upon single loop fractional synthesizers by making the reference tunable and keeping the main PLL in integer mode at all times. The end result is a low-cost, low-SWaP and high-performance RF synthesizer with impressive specs. ERASynth’s phase noise, for example, -125 dBc/Hz at 1 GHz, 10 kHz offset exceeds even some of the premium bench-top signal generators.
Measuring just 10 x 14.5 x 2 cm, ERASynth is equipped with a low-power ±25 ppb OCXO for ultra-stable operation.