Coded acoustic wave modulation for multi-parameter transmission

Improving process observability is of high relevancy to improving manufacturing productivity. This paper describes the a data transmission technique that uses acoustic waves as the means for transmitting multiple parameters (melt temperature, pressure, velocity, and viscosity) that are critical to the monitoring and control of plastic injection molding processes. A coded-acoustic wave modulation scheme enables multi-parameter transmission through an acoustic transmitter with variable gains. This enables selective resonant frequencies that provide the carriers for the individual parameters to be transmitted, while suppressing noise induced in the modulation process. The presented sensor design principle is applicable to a wide range of process monitoring scenarios.