Steven Crabtree

US Patent:

46060510, Aug 12, 1986

Filed:

Nov 10, 1983

Appl. No.:

6/550868

Inventors:

Steven B. Crabtree - Taft TN
Harry Yedid - Huntsville AL
James B. Sherman - Chapel Hill NC

Assignee:

Universal Data Systems, Inc. - Huntsville AL

International Classification:

H03D 300
H04L 2722

US Classification:

375 86

Abstract:

A modem receiver having receiver control, signal detection, and data demodulation implemented with a single general-purpose integrated circuit microcomputer. Novel multirate digital signal processing techniques are included which provide complete real-time recovery of all data and modem signals in a microcomputer integrated circuit having an architecture not optimized for signal processing applications. The resulting techniques extend to more general signal processing applications which may be implemented by other general-purpose microcomputers, programmed signal processors, or specific dedicated hardware logic. The novel modem receiver includes digital FIR filters, performing quadrature signal detection, and post-demodulation data correction with an all-digital second-order carrier recovery loop.