The Air Force Metrology and Calibration Authority (AFMETCAL) has ordered signal source analyzers (SSAs) from Rohde & Schwarz. They will be operated in AFMETCAL’s precision measurement equipment laboratories and Air Force primary standards laboratory. The SSAs are used for calibration of phase noise analog (AM, FM and PM) and digital modulation measurements. For phase noise measurement Rohde & Schwarz has also provided cross-correlation offering very high sensitivity, flexibility and fast measurement speed—all-in-one box.

The SSAs are based on the R&S FSWP, a phase noise and VCO tester, and featuring very high sensitivity thanks to extremely low-noise internal sources and cross-correlation. Due to the low-noise internal local oscillator and a second receive path enabling cross-correlation, it is capable of measuring the phase noise of most commercially available synthesizers and oscillators without any additional options. The sensitivity increases depending on the number of correlations used. With a sensitivity of -166 dBc/Hz at 10 kHz offset at 1 GHz the analyzer meets the U.S. Air Force’s requirements.

The SSA measures amplitude noise as well as phase noise. The results of both measurements can be simultaneously displayed in a diagram or in separate windows. The high-precision sources, in combination with cross-correlation, surpass the accuracy of diode detector-based measurements for AM noise, with a sensitivity up to 20 dB better.

The analyzer's high performance internal sources and largely digital architecture make it faster than test systems that digitize the signal after the phase detector. It takes just minutes to display the phase noise trace of high-end oscillators—a measurement that often took several hours in the past.

The SSA platform is also a full-featured high-end signal and spectrum analyzer with a pre-selection up to 50 GHz and an 80 MHz signal analysis bandwidth for analysis of analog or digital modulated signals like required by the U.S. Air Force. It is an all-in-one solution that allows users to easily switch between various measurement channels. Additional options such as pulsed phase noise, noise figure or ILS/VOR measurements, make SSA unique test instruments with a variety of instruments in a single box.

Also, on the purchase were alignment systems and/or equipment or accessories required for periodic recertification and adjustment of the SSA. Rohde & Schwarz offers a future-proof concept to support long-term programs spanning many years.