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Network Products > Use Cases > Synchronized PCM Recording

Synchronized PCM Recording Use Case

The customer required data acquisition, transmission, and recording from a wide variety of sensors and interfaces. Signals included sensor inputs that ranged from 1 ksps to 20 ksps in channel arrays that ranged from 50 to 111 channels wide. Size limitations and ruggedization specifications were consistent with airborne use under extreme conditions. Centralized programming of the Data Acquisition Units (DAUs) via 5 Mbps CAIS bus was required. Output data to both transmission and recording systems would conform to the IRIG-106 standard.

TTC has supplied the customer with a tested array of miniaturized DAUs, operating at 20 Mbps and synchronized using the IRIG-B standard for time tagging. Single point of programming is accomplished from a laptop computer connected to a Miniature CAIS Data Acquisition Unit (MCDAU) master by RS-232 serial cable. Remote Miniature Wideband Data Acquisition Units (MWDAUs) and an Airborne Instrumentation Multiplexer (AIM) unit provide safety of flight data via the CAIS bus. All wideband DAUs acquire sensor data via simultaneous sampling at 16-bit resolution. They output encoded data to the AIM for recording. In addition, the MCDAU relays some PCM data in real time to the ground station via an RF data link transmitter.

The AIM unit multiplexes the acquired input data into Chapter 10-compliant data packets. The single high-speed data transport stream is carried over 1.0625 Gbps electrical fibre channels for recording on a Chapter 10-compliant recording system.

For details of the hardware and technology used, please see web pages describing MCDAU, MWDAU, and Airborne Instrumentation Multiplexer (AIM).