Telemetering of biomedical data from unrestrained subjects
requires a system to be compact, reliable and efficient.
A survey of the existing multi-channel biomedical telemetry
showed that most of the systems employ analogue or uncoded (digital)
techniques of encoding biomedical signals. These techniques are
less reliable, employ wider bandwidth and are difficult to implement
compared to the coded (digital) techniques of modulation.
A theoretical study of the coded techniques of modulation for
encoding biomedical signals showed-that pulse code modulation,
though more efficient, calls for extensive circuitry and makes it
expensive and difficult to implement. Delta modulation and
delta sigma modulation were found to be simpler, easier to Implement
and efficient. [Continues.
