BIOAKUSTIK.ppt

Dr. Cuk Imawan, SP-2007

Bio-akustik


Kata kunci:• Ultrasosound• Wave • Frequency• Echoes• Scan• Transducer


Kata kunci:• Doppler


Kata kunci:• Echoes


Pemahaman yang diperlukan untuk menciptakan aplikasi bioakustik

• Vibrasi/osilasi• Frekuensi• Gelombang• Doppler• Sound (akustik, ultrasonik)• Echoe


Osilasi


Periode

Frekuensi

Persamaan Osilasi


KecepatanOsilasi

PercepatanOsilasi


xmax = A

t = 0

AmplitudoOsilasi


Contoh Osilasi Harmonis Pegas


Energi Potensial

Energi Kinetik

Energi Mekanik osilasi harmonis pegas


Udara

GELOMBANG


Gerak arah -x

Gerak arah +x


Persamaan Gelombang suara

Persamaan Gelombang

Penyelesaian

Kecepatan suara


Energi gelombang suara

Laju energi:

Intensitas ~ Amplitudo kuadrat

Intensitas ~ Tekanan max. kuadrat


Efek Doppler


Kata kunci:• Vibration


Ultrasound imaging is based on the pulse-echo principle, which is also the basis of radar, and came into use as a medical imaging technique after WW2. Ultrasound imaging uses ultra-high-frequency sound waves (3-10 MHz). Human hearing is much lower frequency (in the range of 20 to 20 000 Hz) and therefore you cannot hear the sound waves being given off by the ultrasound imaging machine. A transducer (a device that converts one form of energy to another) is placed on the skin. Ultrasonic waves are emitted by the transducer and they travel through human tissues at a velocity of approximately 1540 m s-1.

When the wave reaches an object or surface with a different texture or acoustic nature, a wave is reflected back. These echoes are received by the apparatus, changed into electric current and a 2-D image is produced.

BIOAKUSTIK.ppt

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