Shown on this slide are the basic signal path blocks for the B-mode, color flow, and Spectral Doppler modes found commonly in ultrasound systems. The RF demodulation block removes the carrier signal from the echoes produced by the tissue and vessel walls and each scan line is processed independently by mixing it with sinusoid to produce in-phase and quadrature components, followed by low pass filtering and decimation. For B-mode processing, envelope detection and log compression routines are used to extract and show the intensity of the echoes for display using a grey scale map. This produces the brightness mode image that is commonly seen. ColorFlow is a mode where the mean of velocity or motion of blood flow is displayed for blood vessels in the region of interest. Mean velocity is accomplished using Doppler techniques on the DSP. The color flow wall filter removes the motion contribution from the vessel walls, then the correlation and parameter estimation blocks employ time-domain techniques to estimate the mean velocity, flow power, and turbulence of the blood flow. This information is fed through a color map and is overlaid on the B-mode image of the blood vessel to show the color flow blood movement, red indicates movement towards the transducer and blue away from it. Some of the common signal processing routines performed in this application are matrix filtering, first lag auto-correlation, and arcTan. TI provides these blocks in the available DSP medical imaging software toolkit. Finally, the Spectral Doppler mode is the quantitative distribution of blood flow at any given point of interest. Doctors use this mode for a quantitative analysis of blood flow.