29-05-2012, 01:18 PM
Generalized instrumentation system
Generalized instrumentation system .ppt (Size: 210 KB / Downloads: 60)
Sensor and Transducer
Transducer
Converts one form of energy to another
Sensor
Converts a physical measurand to an electrical output
Interface with living system
Minimize the energy extracted
Minimally invasive
Signal Conditioning
Amplification
Filtering
Impedance matching
Analog/Digital for signal processing
Signal form (time and frequency domains)
Medical Measurement Constraints
Magnitude and frequency range of medical measurand are very low
Proper measurand-sensor interface cannot be obtained
Medical variables are seldom deterministic
External energy must be minimized to avoid any damage
Equipment must be reliable
Classification of Medical Instrument
Quantity that is sensed
pressure, flow, temp
Principle of transduction
resistive, capacitive, electrochemical, ultrasound
Organ system
cardiovascular, pulmonary, nervous
Medicine specialties
pediatrics, cardiology, radiology
Interfering and Modifying Inputs
Desired Inputs: measurands that the instrument is designed to isolate.
Interfering Inputs: quantities that unintentionally affect the instrument as a consequence of the principles used to acquire and process the desired inputs.
Modifying Inputs: undesired quantities that indirectly affect the output by altering the performance of the instrument itself.