Vocoder Development

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Introduction

In the 1950s, Lincoln Laboratory conducted research on detecting pitch in speech, which subsequently influenced the development of voice coders, commonly known as vocoders. The term "vocoder" is derived from "voice" and "coder." These devices are designed to decrease the amount of bandwidth required for transmitting speech. This reduction in bandwidth offers two advantages: it reduces the cost of transmitting and receiving speech, while also enhancing the potential for maintaining privacy.[1]

Initially, it described a device designed to compress speech for efficient transmission over telephone lines. The idea involved splitting speech into parts using filters and then reconstructing it on the other end. The goal was to save bandwidth, but in practice, it fell short due to the need for numerous filters to maintain speech quality. Additionally, the original vocoder only transmitted loudness, not sound quality.

Subsequently, the "phase vocoder" emerged as an enhanced version, preserving both loudness and sound quality. Further refinements by various researchers improved the method's efficiency without compromising audio fidelity. [2]

Historical Context

Chenyi

Key Innovations

Amber

Impact

Wenjun

Future Research

Alice

LLM Review

Erin

References

Team Members

Alice Vanni, Amber, Chenyi, Erin Shi, Wenjun