On the application of signal compression using Golay's codes sequences in ultrasound diagnostic

The issue of maximizing penetration depth with concurrent
retaining or enhancement of image resolution constitutes one of the time
invariant challenges in ultrasound imaging. Concerns about potential and
undesirable side effects set limits on the possibility of overcoming the
frequency dependent attenuation effects by increasing peak acoustic amplitudes
of the waves probing the tissue. To overcome this limitation a pulse compression
technique employing 8 bits Complementary Golay Code (CGS) was implemented at 4
MHz. In comparison with other, earlier proposed, coded excitation schemes, such
as chirp, pseudo-random chirp and Barker codes, the CGS allowed virtually side
lobe free operation. Computer simulation results for CGS pulse compression are
presented. Next, the images of RMI tissue phantom generated by those two
excitations schemes are presented. Identical peak power conditions in the
experimental setup were implemented with the earlier mentioned 8 bits CGC and 2
periods tone burst. Experimental data indicate that the quality of CGS images is
comparable to that acquired using conventional pulse imaging. CGS exhibited
signal-to-noise ratio (SNR) gain of 9.6 dB with the axial resolution being
virtually the same for both transmitting schemes.