Test system with digital calibration generator

A computerized test system for digital audio devices, comprising:

• a personal computer operatively connected to a sound card,
• said sound card comprising a sound card input for receipt of an analog test signal, an A/D converter adapted to convert the analog test signal to a digital test signal, a D/A converter operatively coupled to a signal receipt channel for receipt of a digital response signal and for conversion into an analog output signal provided on a sound card output;
• a digital calibration generator adapted to generate a digital calibration signal of predetermined level and spectral content according to calibration signal data supplied by a calibration program executable on the personal computer;
• a data communication interface being adapted to transmit and/or receive data in accordance with a predetermined communication protocol,
• the data communication interface comprising an encoder adapted to receive, encode and transmit the digital test signal or the digital calibration signal to an external digital audio device and a decoder adapted to receive and decode an encoded digital response signal from the external digital audio device to provide the digital response signal to the signal receipt channel;
• and
• a switching arrangement, operating in accordance with a mode control signal supplied by the calibration program, configured to selectively operate the computerized test system in either:
• a first mode wherein the digital calibration signal is routed through a cascade of the encoder and decoder to couple the digital calibration signal to the signal receipt channel or
• a second mode wherein the digital test signal is routed through the data communication interface to the external digital audio device.