Pr

1

Experimental results
Signal to Noise of the reconstructed impulse
responses. - BLUE normal correlations -RED 1
bit correlations. 1bit processing gives better
results because it tends to give more weight to
the latest signals (longest paths)
Experimental IMAGE of the 4 layers media. -
BLUE Sound speed profile before heating up the
sample by 8 C. - RED Sound speed profile after
heating up the sample by 8 C.
References 1 O.I. Lobkis and R.L. Weaver, J.
Acoust. Soc. Am. 110, 6 (2001). 2 R. L.
Weaver, O. I., Phys. Rev. Lett. 87, (2001). 3
T. L. Duvall et al, Nature 362 (1993). 4 T. L.
Duvall et al , Solar Physics, 170, 63-73
(1997). 5 Campillo M., Paul A., Science, 299
(5606), 547-549 (2003). 6 Hennino R. et al.,
Phys. Rev. Let., 86, 3447-3450 (2001). 7 K. G.
Sabra et al, J. Acoust. Soc. Am. 114, 2462
(2003). 8 A. Derode et al, Journ. Acoust. Soc.
Am. 113 (6) (2003). 9 A. Derode et al, Appl.
Phys. Lett. 83, (15) 3054-3056 (2003). 10 B.A.
Van Tiggelen, submitted to Phys. Rev. Lett.,
2003.
What is 1bit processing?
We just record and correlate the sign (1 or 1)
of the field.