Analog feedback shift register
An analog feedback shift register (AFSR) is a generalization of the (binary, digital) linear feedback shift register (LFSR).
While binary LFSRs require less power to generate spread-spectrum signals than AFSRs, AFSR receivers require less power (in theory) to synchronize to those signals than binary LFSR receivers.
As of 2005, AFSRs are still in research. AFSR techniques could make spread-spectrum receivers (such as GPS receivers and cell phones and WiFi receivers and RFIDs) cost less and have longer battery lifetimes.
- A Nonlinear Dynamic System for Spread Spectrum Code Acquisition by Benjamin Vigoda 1999
- C/A-code Synchronization Using Analog Feedback Shift Registers (AFSR) by Daniel Megnet-Kägi, et al. 2004
- Pseudo-noise Sequences based on Algebraic Feedback Shift Registers by Mark Goresky and Andrew Klapper (2005??)
- Fast Acquisition GPS Receivers by H. Mathis, HSR Rapperswil 2004