Design of huffman sequences with limited bandwidth

3D USCT II is a new imaging method aimed at early detection of breast cancer. Synthetic aperture focusing technique is used for reconstructing images which requires unfocused ultrasound emission and reception. Thus the SNR received is low. Coded excitation (CE) and match filtering techniques are used to increase the SNR. The Currently applied CE is a linear chirp. The received A-scans contain multiple superimposed reflections which are difficult to separate due to the system´s limited bandwidth side lobes. Literature suggests Huffman sequence (HS) as CE to gain more control over side lobe distribution. Since the system has limited bandwidth, the HS is received band limited and which does not produce satisfactory results. A method is presented here to design HS under limited bandwidth preserving their good properties. The evaluation has been carried out with well established metrics like MSR and SLD. The results show better performance than using a chirp for side lobe suppression by trading-off main lobe energy.