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  2. Finite-state transducer - Wikipedia

    en.wikipedia.org/wiki/Finite-state_transducer

    A finite-state transducer (FST) is a finite-state machine with two memory tapes, following the terminology for Turing machines: an input tape and an output tape. This contrasts with an ordinary finite-state automaton, which has a single tape. An FST is a type of finite-state automaton (FSA) that maps between two sets of symbols. [1]

  3. Ultrasonic transducer - Wikipedia

    en.wikipedia.org/wiki/Ultrasonic_transducer

    The transducer may be used in contact with the skin, as in fetal ultrasound imaging, or inserted into a body opening such as the rectum or vagina. Clinicians who perform ultrasound-guided procedures often use a probe positioning system to hold the ultrasonic transducer. [9] Compared to other medical imaging modalities, ultrasound has several ...

  4. Phased array ultrasonics - Wikipedia

    en.wikipedia.org/wiki/Phased_array_ultrasonics

    By changing the pulse delays, the computer can scan the beam of ultrasound in a raster pattern across the tissue. Echoes reflected by different density tissue, received by the transducers, build up an image of the underlying structures. Weld examination by phased array. TOP: The phased array probe emits a series of beams to flood the weld with ...

  5. Ultrasound - Wikipedia

    en.wikipedia.org/wiki/Ultrasound

    Ultrasound is defined by the American National Standards Institute as "sound at frequencies greater than 20 kHz". In air at atmospheric pressure, ultrasonic waves have wavelengths of 1.9 cm or less. Ultrasound can be generated at very high frequencies; ultrasound is used for sonochemistry at frequencies up to multiple hundreds of kilohertz.

  6. Ultrasonic testing - Wikipedia

    en.wikipedia.org/wiki/Ultrasonic_testing

    The transducer is typically separated from the test object by a couplant [4] such as a gel, oil or water, [1] as in immersion testing. However, when ultrasonic testing is conducted with an Electromagnetic Acoustic Transducer (EMAT) the use of couplant is not required. There are two methods of receiving the ultrasound waveform: reflection and ...

  7. Sound from ultrasound - Wikipedia

    en.wikipedia.org/wiki/Sound_from_ultrasound

    Sound from ultrasound is the name given here to the generation of audible sound from modulated ultrasound without using an active receiver. This happens when the modulated ultrasound passes through a nonlinear medium which acts, intentionally or unintentionally, as a demodulator .

  8. Piezoelectric micromachined ultrasonic transducer - Wikipedia

    en.wikipedia.org/wiki/Piezoelectric_micro...

    Piezoelectric micromachined ultrasonic transducers (PMUT) are MEMS-based piezoelectric ultrasonic transducers.Unlike bulk piezoelectric transducers which use the thickness-mode motion of a plate of piezoelectric ceramic such as PZT or single-crystal PMN-PT, PMUT are based on the flexural motion of a thin membrane coupled with a thin piezoelectric film, such as PVDF.

  9. Ultrasonic flow meter - Wikipedia

    en.wikipedia.org/wiki/Ultrasonic_flow_meter

    Schematic view of a flow sensor. An ultrasonic flow meter is a type of flow meter that measures the velocity of a fluid with ultrasound to calculate volume flow. Using ultrasonic transducers, the flow meter can measure the average velocity along the path of an emitted beam of ultrasound, by averaging the difference in measured transit time between the pulses of ultrasound propagating into and ...