Tone Event Detection in Packet Telephony Using the StarCore™ SC140 Core

1 Tone Event Detection Basics 2 1.1 Tone Event Detector Architecture 2 1.2 Phase Detection With Frequency Offset Compensation 4 1.3 Summary of Theoretical Results 6 2 Tone Event Detector on StarCore 8 2.1 Automatic Level Control (ALC) 8 2.2 Tone Indication 9 2.3 Tone Indicator Counter 9 2.4 Finding the Closest Reference Frequency Tone .......10 2.5 FIR Filtering Implementation 10 3 Tone Events in Packet Telephony 11 4 RFC2833 Overview 11 4.1 Payload Format for Named Telephone Events .........12 4.2 Sending and Receiving Named Telephone Event Packets 15 4.3 Payload Format for Telephony Tones 16 4.4 Multiple Tones and Named Events in One Packet ...17 5 Conclusion 20 6 References 21 Tone Event Detection in Packet Telephony Using the StarCoreTM SC140 Core