Receiver NLEQ Technology
As radar and communication systems push to higher and higher processing speeds, distortions in components such as analog-to-digital converters (ADCs) and low-noise amplifiers (LNAs) often become the limiting factor in system performance. By providing a parsimonious real-time algorithm for reducing these distortions—utilizing polynomial signal approximations of the distortions—NonLinear EQualization (NLEQ) provides a powerful means to regain dynamic range lost to distortion. Real system data* has been demonstrated to typically regain 27 dB or more dynamic range with this approach.
Developed collaboratively at GMR and Lincoln Laboratory, NLEQ began Phase II development in 02/06. Deployment in a real world system is expected in early 2008 at Northrop Grumman.
* measured on a MAX108 high-speed ADC, operating at 1.5 GSps with instantaneous band width of 500 MHz
Nonlinear Affine (NoLAff) processing:
Nonlinear Affine (NoLAff) processing is a novel class of signal processing techniques that treats nonlinear effects (intentional or coincidental) as beneficial to system performance. It treats nonlinear distortion artifacts (e.g., intermodulations and harmonics) as a form of signal diversity which yields additional information about the signals of interest.
The first application and development of NoLAff signal processing began with the DARPA Analog-to-Information (A2I) program. A2I is an exploratory development program aimed at demonstrating efficient means for detecting and reconstructing sparse information. NoLAff signal processing has shown it is possible to sample sparse data well below the ‘traditional’ Nyquist rate while reconstructing the full signal with lower noise and with less power consumption.