This Report was presented to the Faculty of the Graduate School of the University of Texas at Austin in partial fulfillment of the requirements for the degree of

Master of Science in Engineering

The use of microcontrollers for embedded applications has become commonplace. Microcontrollers provide single-chip, low-cost solutions for low-bandwidth, low-power applications. In this report, I present two communication applications and two new approaches to realize these applications on a PIC microcontrollers from Microchip Technology Inc.

I present a new approach to decode the WWVB broadcast time information transmitted by National Institute of Science and Technology (NIST) and generate an accurate frequency reference calibrated to the NIST primary standard. The key innovations are new, zero-buffering solutions and microcontroller implementations to decode WWVB time code information and the use of a pulse-width modulator to generate an accurate frequency reference.

In this report, I also present a new, low-complexity ITU-compliant algorithm for Dual Tone Multiple Frequency (DTMF) touchtone signal detection. The key innovations include the use of adaptive notch filtering, accurate frequency estimation techniques, and new sophisticated validation logic to check whether a detected DTMF digit satisfies the ITU requirements. The proposed method is the first zero-buffering, ITU-compliant method that can be implemented on an 8-bit microcontroller.