= Analyzing the PJMEDIA Tone Generator Algorithms Performance =

This article presents the performance analysis of various back-end algorithms of the tone generator that are implemented in PJMEDIA. We will measure the performance in both speed and accuracy terms.

== The Algorithms ==

The tone generator (tonegen.c) supports several algorithms, and since version 1.0-rc3, the use of these algorithms is controlled by {{{PJMEDIA_TONEGEN_ALG}}} setting:
 - {{{PJMEDIA_TONEGEN_SINE}}}: The good-old generation using math's sine(), floating point. This has very good precision but it's the slowest and requires floating point support and linking with the math library.
 - {{{PJMEDIA_TONEGEN_FLOATING_POINT}}}: Floating point approximation of sine(). This has relatively good precision and much faster than plain sine(), but it requires floating-point support and linking with the math library.
 - {{{PJMEDIA_TONEGEN_FIXED_POINT_CORDIC}}} (new in 1.0-rc3): Fixed point using sine signal generated by Cordic algorithm. This algorithm can be tuned to provide balance between precision and performance by tuning the {{{PJMEDIA_TONEGEN_FIXED_POINT_CORDIC_LOOP}}} setting, and may be suitable for platforms that lack floating-point support.
 - {{{PJMEDIA_TONEGEN_FAST_FIXED_POINT}}}: Fast fixed point using some approximation to generate sine waves. The tone generated by this algorithm is not very precise, however the algorithm is very fast.

== Accuracy ==

For the accuracy test, we setup the tone generator to generate digit A from [http://en.wikipedia.org/wiki/DTMF DTMF], with frequencies of 697 and 1209. We then analyzed the frequency using !CoolEdit (now becomes [http://www.adobe.com/special/products/audition/syntrillium.html Adobe Audition]).