DRS Signal Solutions of Germantown, MD., invited Dr. Nicholas Cianos, Executive Staff Scientist, at WGS Systems LLC to present a paper on wideband tuner performance in broadband dense signal environments in March 2017.
Dr. Cainos detailed in his presentation titled, “Impact of Wideband Signal Environments on Wideband Tuners’, describes the characteristics of dense signal environments and shows that multiple signal environments behave statistically like Gaussian noise.
This noise like behavior has a significant impact on wideband tuners and results in a dramatic increase in intermodulation spurious signals or simply spurs. The spurious signals result from nonlinearities within the tuner. They impact a tuner and signal processing system and potentially limit the detection of desired signals since the desired signal can be masked by the spurs.
In his presentation, Dr. Cainos illustrates the effects of a multitone signal environment on a typical tuner and shows how the multitone signal environment compares with the traditional two-tone intermodulation test. It relates the multitone environment to the concept of Noise Power Ratio, a wideband test concept using Gaussian noise. The paper suggests that NPR provides an alternate approach for testing and measuring wideband tuners.
The first briefing provided the motivation for generating the second paper on Wideband Tuner NPR performance.
Radio tuner designers traditionally use two-tone intermodulation testing to characterize the nonlinear behavior of tuners. The two-tone test results specify tuner performance in terms of its second and third order intercept points, IP2 and IP3. Although these performance measures are important they do not describe the behavior of the tuner in wideband dense signal environments. The second briefing describes the relationship between NPR and IP2/IP3 and shows NPR performance differences between high-performance tuners and lower performance tuners.
The second paper also presents a system perspective of NPR. Modern tuners typically combine the analog segment of the tuner with an Analog-to-Digital converter. It shows that the total tuner NPR depends on the individual NPRs of the analog tuner segment and the Analog-to-Digital converter segment.
In summary, both papers provide developers and system designers with the knowledge needed to design radio systems that can be used in modern wideband dense signal environments.
Dr. Nicholas Cianos has a unique background of radio physics, SIGINT, communications and systems. He has developed ELINT and COMINT intercept and direction finding systems from HF through the microwave spectrum. He is currently the Executive Staff Scientist at WGS Systems LLC. a leading provider of C4ISR systems.
He is responsible for the development of high performance of ISR and communication networked products and systems from HF through microwave with an emphasis on manpack, ground based and airborne architectures.