Charge-coupled device pseudo-noise matched filter design

The design and fabrication of practicable CCD IC´s as pseudo-noise matched filters (PNMF´s) for direct-sequence spread-spectrum signals is described. After a brief explanation of CCD PNMF´s, desirable architectural features for an IC are presented. A state-of-the-art fully integrated 512-cell CCD PNMF is used as an example. Next, PNMF design considerations dealing with device limitations, sampling errors, and carrier-frequency offsets are addressed. The application of PNMF´s to various modulation formats is treated, along with approaches to increased sampling resolution. Finally, laboratory measurements for a 128-cell PNMF as well as a 512-cell PNMF formed by a tandem connected of four of the former are presented. Multiple access, a 60-dB dynamic range, and 0.75 percent linearity were achieved with the former, while the latter correlated 255 chips in a double-sampled configuration.