Speech Coders and the Fundamentals of Modern Communication

by | Sep 16, 2014 | software

The best and most professional workplaces know how to work a little technical magic.

You wouldn’t know it at first glance, but there’s typically an array of invisible technologies that keep the workplace running like a well-oiled machine.

Speech coders are part of that modern technological magic show, as they’re integral to the proper functioning of virtually every type of electronically-based communications, including public switched telephone networks, or PSTNs – something that we all use. Speech coders are also central to the successful operation of videoconferencing setups, cellular communication, and Internet protocol applications, or VoIPs. In other words, speech coders are used for virtually every type of communication, in and out of work.

What Speech Coders Do

Speech coders serve as digital abbreviators in that their function is to digitally represent human speech using as few bits, or as little data, as possible while upholding the integrity of speech required for the specific application. Part art and part science, speech coders are designed to generate representations of speech that can then be digitally stored or transmitted. Those signals are then decoded in the highest possible quality.

The underlying need for speech coders, of course, is the conservation of bandwidth in environments that require the transmission of large quantities of data and that accommodate a high number of digital communications.

Lowering bit rate to conserve bandwidth also carries with it the potential for lowered voice quality and, ultimately, intelligibility. Therefore, in considering all of the potential constraints of individual applications, too low a bit rate for some could be too high a rate for an others.

Speech coders configure digital speech into code that is typically transmitted into frames. It stands to reason, then, that speech decoders take that code and reconfigure it back into speech at a desired or at least more ideal, bit rate.

It’s worth noting that speech coding involves a much simpler signal as compared to other types of audio signals, as speech itself is easier to process. The primary rule of thumb that pertains to speech coding, and one that does not pertain to other types of audio signals, is that the general goal is to maintain a level of speech that is pleasing to the ear.

Additionally, well-performed speech coding should similarly preserve intelligible speech, in addition to less quantitative properties like as emotions and tone, the facets that make speech especially human.

Like so much of modern technology, speech coding is an art and a science, as the ultimate mission is to efficiently digitally transmit essential humanity across miles, through digital devices, and airwaves. Speech coders assist us in effective communication by delivering digital convenience while retaining that irreplaceable human quality.