ELECTROMAGNETIC SPECTRUM

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MEDICAL INSTRUMENTATION II
ELECTROMAGNETIC SPECTRUM BIOMEDICAL
ENGINEERING 2006200401 TAE_EUI, KIM
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Electromagnetic Spectrum

• Audio freq.
• Radio freq.
• Microwave
• Infrared
• Visible light
• Ultraviolet
• X-ray
• R-ray

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Audio frequency
No change with respect to area or position
Because its too low freq. long wave length to
neglect
Independent on position
ECG bit overlapped, similar to the range of
EMG. EEG is lower than 20Hz No sound from speaker
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Radio frequency

• Low freq. 30kHz 300kHz
• (10km 1km)
• Medium freq.300kHz 3MHz
• (1km 100m)

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Radio frequency

• High freq.3MHz 30MHz
• (100m 10m)

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Radio frequency

• High freq.3MHz 30MHz
• (100m 10m)

Able to describe magnitude of each wave at the
same time. WAVE PROPAGATION In high frequency
range, as circuits get bigger, we cannot say it
is a same signal. Possible to adjust Circuit
Analysis within 1M (Low freq.) whereas not to
adjust Circuit Analysis over 1M (High freq.)
Differentiate by means of time The length
of antenna should be longer than half of wave
length. The reason to try to use high
Freq. Antenna can be shorter.
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Radio frequency

• Very High freq. (VHF) 30MHz 300MHz
• (10m 1m)
• Ex) TV
• Ultra High freq. (UHF) 300MHz 3GHz
• (1m 0.1m)
• Ex) Mobile

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Microwave

• Centimeter Wave 3GHz 30GHz
• (10cm 1cm) Heavily Comm.
• Ex) Satellite
• Millimeter Wave 30GHz 300GHz
• (10mm 1mm) High comm.
• Sub-millimeter Wave 300GHz 3THz
• ( 1mm 0.1mm )Not so much

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Infrared
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Visible light
Reflect our body
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Ultraviolet

1. X - ray

1. R - ray

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In summary
Things emit electromagnetic
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Radiation Thermometer

• Thermometer

• Radiation Thermometer

Shutter
Lens
IR Sensor
Pyroelectric Sensor