US 6,983,025 B2
High quality power ramping in a communications transmitter
Stephan V. Schell, San Francisco, Calif. (US)
Assigned to Tropian, Inc., Cupertino, Calif. (US)
Filed on Apr. 11, 2001, as Appl. No. 9/833,967.
Prior Publication US 2002/0176514 A1, Nov. 28, 2002
Int. Cl. H04L 25/03 (2006.01)
U.S. Cl. 375—296 33 Claims
OG exemplary drawing
 
1. A method of controlling ramping of a communications signal including amplitude modulation between two states including a state of minimal output power of the communications signal during which no information is conveyed and a state in of greater output power in which information is conveyed, the method comprising:
adding a predetermined sequence of symbols to a sequence of information symbols to be communicated to form an augmented sequence of symbols; and
performing modulation of the augmented sequence of symbols to produce an envelope signal that exhibits a desired ramp profile,
wherein adding said predetermined sequence of symbols is performed in a manner that ensures a transient spectrum of the envelope signal during ramping is no worse than the transient spectrum during information bearing modulation.