Echocardiogram_summary - in the carrier signal which is...

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ECHOCARDIOGRAM Summary Echocardiogram is a test in which ultrasound is used to examine the heart. There are different properties of ultrasound which are used in order to obtain an effective recording of the heart. The frequency is selected on the basis of examination taking into consideration the echo strength and patient safety. A technique, Pulsed Doppler Echocardiography is commonly used for blood velocity measurement as a diagnostic tool, which is an indicator of pathological conditions related to heart. Signal processing done in the acquisition of data from the ultrasound waves is a complex process and involves multistage refinement of received echoed signal from the heart. Though, there are many different ways of refining signal to obtain faithful velocity measurement, but a commonly used process involves process of demodulation, which is a commonly employed technique in communication. Coherent Demodulation is employed to obtain the frequency shift
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Unformatted text preview: in the carrier signal which is then further processed through series of steps to give a pulsed Doppler echocardiogram pattern. To convert the signals into an image we first must deconvolute our signal with the impulse response. However the signal we obtain from this is our target along with some random noise. There are several methods and on going research on improving this. The traditional method is by use of Fourier transforms. Newer methods include auto regression which currently results in better resolution then the Fourier way. Images are shown in B-mode, which is the energy of the signal shown in grayscale in a dot or pixel. A 1D pulse is sent out over a 90 degree angle from a single point, since the data is obtained in polar coordinates, it is converted to rectangular coordinates. Interpolation is used to fill in the gaps between scan lines. From there we are able to get a 2D image....
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This note was uploaded on 02/27/2008 for the course BME 501 taught by Professor Yamashiro,hsiai during the Fall '07 term at USC.

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