Douglas Millar is listed as inventor in the following US patents. Most are also registered in other countries.

• Cellular telephone audio input compensation system and method, US 5,852,769
  
  
• Radio transceiver with impedance matched test port, US 5,710,984
  
  
• System and method of measuring a battery lifetime, US 5,684,404
  
  
• Power detector using a constant quiescent voltage divider, US 5,675,245
  
  
• Adaptive sparse echo canceller using a sub-rate filter for active tap selection, US 5,343,522
  
  
• Transmission error protection for TDMA digital channels, US 5,121,395
  
  
• Echo cancellation in two-wire transmission path repeaters, US 4,782,525
  
  
• Adaptive differential PCM system with residual-driven adaptation of predictor coefficients,
  US 4,593,398