xiotechnologies / x-osc-latency-tester

x-OSC-Latency-Tester

This repository includes the source files for the tools used to evaluated the closed-loop latency of x-OSC communicating with a host. The closed-loop latency is the delay between a physical change on an input pin and the resulting physical change on an output pin. This delay includes: sampling of x-OSC input pin, WiFi transmission from x-OSC to computer, processing of received data by computer, WiFi transmission from computer to x-OSC, setting x-OSC output pin.

A windows application and simple hardware setup allow the latency to be measured repeatedly and autonomously. In this setup, an x-OSC digital input is connected to a 1 Hz square wave while the Windows application communicating with x-OSC creates the behaviour: output = input. Both the input and output are connected to an XOR gate to generate a pulse width equal to the delay between the input and output pin state changes. This pulse width is measured using a TTi TF930 frequency counter which sends the measurement to the Windows application via USB to be logged to a CSV file.

The repository includes the results of investigations into the closed-lop latency for various scenarios and a MATLAB script for plotting these distributions. Images of the hardware setup and ultimate distribution plots have also been included.

The method for evaluating latency was original presented in a 2013 paper at the Sound and Music Computing conference.

Hardware Setup

Ad hoc latency distribution