1. Instrumentation System  A Measuring system is required to compare a quantity with a standard or to provide an output that can be related to the quantity being measured  The quantity to be measured is detected by an input transducer or sensor.  The detected quantity may be converted to a mechanical or electrical form of energy Display Recorder Signal conditioner Measurand Sensor Input Output

2. Instrumentation System Dashed lines are optional for some applications Primary sensing element Measurand Variable conversion element Calibration signal Signal processing Power source Data storage Data transmission Output display Control and feedback Radiation, electric current, or other applied energy Sensor Perceptible output

3. Clinical Instrument  Black box  Need many kinds of Instruments  Expensive EMG Instrument ECG Instrument Blood Pressure Instrument ．．．．．． Clinical Instrument

4. Clinical Instrument (cont.) A/D Converter Oscilloscope LCD Process Circuit Sensor surface electrode pressure transducer photocoupler temperature sensor pressure gauge strain gauge ： PC

5. Definitions  Measurand (Physical quantities):  Position, displacement  Temperature  Force  Pressure,…  Concentrations, chemicals,…,  Sensor:  is a device that detects a change in a physical stimulus and turns it into a signal which can be measured or recorded  Signal conditioning:  Amplifying, wave shaping, filtering, rectifying,…  Transducer:  is a device that transfers power from one system to another in the same or in a different form.