Microprocessor based WWVB receiver with
integrated antenna and real time clock
The Ultralink 325 provides accurate time and date
information referenced to the United States Atomic Clock Standard. The unit
receives VLF (very low frequency) radio signals broadcast by WWVB operated by
the National Institute of Standards and Technology (NIST).
The receiver incorporates a high quality ferrite
loop stick antenna, factory tuned for maximum sensitivity and selectivity. The
receiver uses base band amplification with crystal band pass filtering. A
demodulator provides a digital output corresponding to received signal data.
A microcomputer processes WWVB signals, maintains
an accurate real time clock and hosts the serial communication interface.
Received data is correlated over time to set an internal real-time clock (RTC).
The RTC is driven by a precision quartz crystal for continuous accurate time
reference. Power circuitry provides internal operating voltages and maintenance.
- Receiver Location
The antenna/receiver unit is designed to be used indoors in a wood frame
- Operation deep inside metal buildings or buildings
with metal reinforcements may be marginal.
- The antenna/receiver should be mounted with
the long side horizontal. It may be mounted flat (table/ shelf) or vertical
- The antenna/receiver is directional with best
reception obtained with the long side perpendicular to Fort Collins, Colorado.
- Orient the antenna/receiver for steady
blinking of the power/signal LED. After final orientation secure receiver to
prevent inadvertent movement (double sticky tape is OK).
- Avoid locating near suspected interference
sources such as:
- Lamp dimmers Fluorescent lamps Electronic
igniters CRT monitors Battery chargers Switching power supplies Motors
Automobile ignition systems Power lines Nearby radio transmitters
In some areas of the country the signal may not be available 24 hours a day. In
these cases setup and initial reception are usually best done at night. The unit
is designed to keep accurate time during marginal reception periods after time
is initially acquired.
The Ultralink 325 comes with a 25 foot interface
cable, with a DB9 serial data connector.