Phase noise can be a limiting factor in communication-system data rates and radar-system accuracy, and it has been a long-time concern for RF/microwave source specifiers in a variety of aerospace and defense (A&D) systems. To establish low-noise standards for a fixed RF source that also aids shrinking size, weight, and power (SWaP) system requirements, along comes the model FXLNS-1000 fixed-frequency 1000-MHz source from Synergy Microwave Corp. It fits a surface-mount-technology (SMT) housing measuring just 1.95 × 1.25 × 0.47 in.
The source's single-sideband (SSB) phase noise is close to instrument measuring limits, though. Its SSB phase noise is typically –140 dBc/Hz offset 1 kHz from the 1-GHz carrier and –154 dBc/Hz offset 100 kHz from the same 1-GHz carrier.
The low-noise SMT source (see image above) draws 200-mA current from a +5-V dc supply and 45 mA maximum from a +12-V dc supply while generating +3-dBm output power. Spurious levels are just –55 dBc. The tiny source requires a reference oscillator with +13-dBm signal power at 100 MHz and phase noise of –138 dBc/Hz extremely close to the carrier, offset 50 Hz, to ensure that the 1000-MHz source achieves its impressive phase-noise performance.