Voice-over Internet Protocol (VoIP) telephony which is the transmission of real-time voice over an
internet protocol (IP) data network, is increasingly becoming a variant telecommunication technology that
one day may surpass the old analog and digital telephone systems. The Quality-of-Service (QoS) factor is
an important parameter to be considered when measuring the performance of a VoIP system. Algorithmic
delay (latency) may influence the QoS of a VoIP system.
This paper presents the hardware implementation of the Open-Loop Pitch Analysis component of the
Conjugate-Structure Algebraic-Code-Excited Linear-Prediction (CS-ACELP) speech compression algorithms.
The Open-Loop Pitch Analysis units were implemented in hardware using Xilinx 11.1 ISE, after which
ITU-T test vectors were used to determine whether they were equivalent implementations of the Open-Loop
Pitch Analysis. The algorithmic delays of hardware-implementations were obtained via simulation using
Modelsim XE 6.4b while the algorithmic delays of the software-implemented speech compression algorithms
were obtained by software profiling using the GPROF profiler.
After comparison the algorithmic delays of the hardware-implementations of the Open-Loop Pitch
Analysis was found to be shorter than the algorithmic delays of their software-implemented and
hardware-implemented counterparts.