A TECHNIQUE FOR VOICE DETECTION IN A PCM SPEAKERPHONE
Original Publication Date: 1985-Oct-01
Included in the Prior Art Database: 2001-Oct-16
A voice detector architecture which operates directly on digitally encoded PCM data is shown in Figure 1. The PCM data, typically 8000 8-bit digital samples per second, enters the detector in either serial or parallel form. The first step is conversion from A-Law or p-Law code to conventional binary code. The sign bit is ignored, which effectively equates to full wave rectification of the signal. Fewer than the remaining seven bits may be used for processing in order to reduce the size of the circuitry. The architecture functions the same regardless of the number of most significant bits used, however, the performance of the detector will degrade as bits are eliminated.