A digital recorder multiplexer/demultiplexer system for data acquisition

Abstract

Test ranges and telemetry facilites are replacing older analog recorders, which require expensive calibration and maintenance with relatively inexpensive digital recorders. Analog recorders have lower bandwidths and are limited to a small number of channels while digital recorders have high bandwidths and the capability to record a much larger number of channels. The use of digital recorders necessitates the conversion of analog signals to a digital format before recording and conversion or the recorded digital data back to analog for playback. Digital recorder systems often must simultaneously record analog signals along with digital signals such as pulse code modulation (PCM) signals. Front-end multiplexers provide the capability to mix multiple signal types on to the recorder's digital data stream while demultiplexers provide playback ability from the recorder. The Inter Range Instrumentation Group (IRIG) defines a formatting standard called ADARIO (Analog Digital Adaptable Recorder Input Output) within the IRlG 106-96 Telemetry Standards. ADARIO defines a format for multiplexing multiple channel data on to a digital recorder. The ADARIO format features high data rates, low data storage overhead and the ability to maintain time coherency during playback of the original signals. The IRIG format provides commonality that ensures cross-ply compatibility between magnetic tape data recorded at one facility and played back at another. It also provides for technology improvements by defining capacities and capabilities that exceed existing technology. The format and its applications are described.