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Code Efficient Bell 103 Equivalent Modem

IP.com Disclosure Number: IPCOM000065543D
Original Publication Date: 1985-Dec-01
Included in the Prior Art Database: 2005-Feb-19

Publishing Venue

IBM

Related People

Authors:
Mueller, JR West, LP [+details]

Abstract

A Bell 103 equivalent modem is illustrated in the block diagram. The unique features of this design include: A. Bandpass Filter 1 is implemented in microcode as opposed to hardware front-end filter (FIR). Signal processor-based modems are hybrid designs, utilizing at least a hardware bandpass filter. A general-purpose signal processor is employed to avoid the use of any hardware filters. Minimal code size allows enough processor time to implement a complex bandpass filter. This also reduces costs by avoiding hardware filters, and allows other applications access to the full signal bandwidth available. B. Off-band tuning of high band filter 2 and low band filter 3 allows single Bi-Quad filters for data separators.