Varying the voltage of a carrier or a direct current in order to transmit analog or digital data. Amplitude modulation (AM) is the oldest method of transmitting human voice electronically. In an ...

SIAM Journal on Applied Mathematics, Vol. 58, No. 6 (Dec., 1998), pp. 1901-1930 (30 pages) We study a class of partial differential equations in one spatial dimension, which can be seen as model ...