Glossary  Glossary-11
VCO See voltage-controlled oscillator.
vector sum excited 
linear predictive 
coding
A voice-encoding technique used in ASTRO digital voice.
VOCON See vocoder/controller.
vocoder An electronic device for synthesizing speech by implementing a 
compression algorithm particular to voice. See also voice encoder.
vocoder/controller A PC board that contains an ASTRO radio’s microcontroller, DSP, 
memory, audio and power functions, and interface support circuitry.
voice encoder The DSP-based system for digitally processing analog signals, and 
includes the capabilities of performing voice compression algorithms or 
voice encoding. See also vocoder.
voltage-controlled 
oscillator
An oscillator in which the frequency of oscillation can be varied by 
changing a control voltage.
Term Definition