Multi-transmitter communication system employing anti-phase pilot signals

A multi-transmitter communication system, comprising:

• an input for receiving a communication signal;
• a plurality of transmitter modules coupled to the input, each comprising a power amplifier;
• a combiner receiving and combining the outputs of the plural transmitter modules;
• and
• a pilot signal source coupled to the plurality of transmitter modules and providing a respective plurality of pilot signals having relative phases so as to combine in an out of phase manner at said combiner when the transmitter modules are aligned.

A method for aligning a communication system comprising at least first and second power amplifier modules in respective parallel signal paths receiving and amplifying an input signal, and a combiner combining the amplifier module output signals, said method comprising:

• providing out of phase pilot signals to respective ones of said parallel signal paths, so that the pilot signals combine out of phase when the system is aligned;
• detecting any residual pilot signal at the combiner output;
• and
• adjusting at least one of the signal paths to minimize the detected pilot signal.