This Project involves synthesis
and the implementation of a sonar receiver intended for obstacle detection and
collission avoidance. A sonar system consists of an array of hydrophones which are
partially or completely submerged in water. A large number of receivers have to be used to
detect these signals. Hence the receiver should not only be sensitive but also cost
efficient.
We use a 1-bit delta sigma modulator as an analog to digital converter because of the high
dynamic range of the pulse density modulated(PDM) output and ease of
implementation.Thereafter instead of using expensive, high Q and thus very sensitive
band-pass filters, we adopt multirate filtering techniques by using sub-sampling mixers or
modulators and lowpass filters. The lowpass/decimator is split into two stages, hence
providing a wide-band as well as narrow-band output.
Sonar Receiver Chip |
Test Board
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