A frequency and phase domain processor for directional Doppler units.
These boards were manufactured by Sonicaid Ltd. for use in their BV380 directional
Doppler-shift velocimeter, shown below :
Typical waveforms from various sites around the human body are :
To demonstrate the capability of the various processors, the resulting Doppler-shifted
blood flow velocity waveforms are shown below :
A & D are from a Time Domain Spectrum Analyser.
B & E are from a Time Compression Spectrum Analyser via phase domain processing.
C & F are from a Time Compression Spectrum Analyser via frequency domain processing.
A - C are from the posterior tibial artery.
D - F show simultaneous arterial and venous flows, with poor signal-to-noise ratio
and in the presence of "wall thump".
This work was done jointly with Dr.M.G.Taylor in Prof.R.G.Gosling's Blood Flow Group
at the Physics Dept., Guy's Hospital Medical School, London,
and was funded by the Wellcome Trust.
Photographs courtesy of Tim Eveleigh, Photographic Dept., Guy's Hospital Medical School, London.