JANUS: General Telemetry Test Transmitter

Abstract: The purpose of this thesis was to develop a device that transmits telemetry
data. The request for such a device was made by RFN – a government
aeronautic test range located near Vidsel, Sweden. The data sent out from
the device will consist of a simulation of a customer’s test flight
transmission.

One of RFN’s demands was that the PCM bit rate of the device would reach 20
Mbit/s. This prohibited the mere use of a PC. Instead, an electronic front-
end was designed and integrated with a PC104, which would contain a web
based user interface as well as serve as real-time sensor reader. These real-
time sensors included a GPS receiver and a flight termination system.

Another demand was that the system would be tough enough to be carried under
a helicopter or towed by a plane, all seasons of the year. Considering this,
the PC104 all electronics had to be rugged and temperature resistant.

The design of the front-end proved to be a challenging task. The sought for
wide tuning possibilities of the finished product called for an advanced
schematic, with 4 different RAM groups and more than 40 other IC’s.

With the current prototype it is possible to set the output bit rate, the
data alignment and the number of bits per word, together with other traits
of the transmitted data matrix.

After the development time and a revision of the project goals, this project
was a success.