Amey Deosthali and Srikanth Gummadi "Low-cost Real-time Decoding of Broadcast Time and Frequency Standard"
Precise frequency and global time information is needed by
The National Institute of Standards and Technology (NIST) formerly the National Bureau of Standards provides this standard for most users in the United States. Radio station WWVB is located near Ft. Collins, Colorado. WWVB continuously broadcasts time and frequency signals at 60 kHz primarily for the continental United States. WWVB transmits a special time code that provides time information. The code provides year, day, hour, and minute information. Other bits provide information about Daylight Savings Time, leap year, leap second, and UT1 correction. In addition the 60kHz carrier frequency provides an accurate frequency standard which is referenced to the NIST Frequency Standard.
As signal processing applications increase so does the need for providing cost-effective solutions. Although current devices exist that provide such time and frequency references, they are rather expensive. Microcontrollers provide effective cost efficient solutions for low bandwidth applications which do not require a lot of processing power. This application is a perfect example that can be implemented on a microcontroller.
We would like to use a low-cost microcontroller to decode the WWVB signal and derive a frequency standard and an accurate clock. We would implement the decoding on a PIC microcontroller from Microchip Technology Inc. We choose PIC 16C71 because of its (1) Low cost and (2) Harvard Architecture (which is similar to DSP).
PIC16C71 is an 18-pin microcontroller with an internal 8-bit analog to digital converter. All of the instructions are single cycle instructions (200 ns with a 20 MHz clock input) except for program branches which are two cycles. It also has an 8-bit timer-counter and a watchdog timer. We will first be developing the application on a simulator and then transferring it to a PIC hardware board.
This application is suited for implementation in the Synchronous Dataflow (SDF) domain. We will first be developing the application on a simulator and then transferring it to a PIC hardware board.