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Software-Based Ring/LIU/PPU Detection


应用笔记 5020

Software-Based Ring/LIU/PPU Detection

By: Jeff Sorensen

摘要 : This application note describes how to implement ring, line-in-use (LIU), and parallel pickup (PPU) functions using the Teridian \"energy detect\" software. This method, used with the Teridian 73M1903 and 73M1903C modem analog front-ends (AFEs), reduces the overall bill-of-material (BOM) cost associated with implementing embedded soft modems. Fundamental to the technique is the utilization of three system resources: constant analog caller ID signal path, digital signal processing in host, and the 73M1903 and 73M1903C's internal dedicated signal boost capability.