Communication system with end-to-end quadrature balance control

A digital communication system which ameliorates a bit error rate of a data stream while communicating said data stream, said system comprising:

• a first receiver located at a first site;
• a first transmitter located at said first site, said first transmitter being configured to generate a quadrature balance signal which alters one of first and second quadrature-phase signals relative to the other, said first and second quadrature-phase signals collectively conveying said data stream, and said first transmitter being configured to combine said quadrature-phase signals to form a communication signal and to transmit said communication signal;
• a second receiver located at a second site, said second receiver being configured to receive said communication signal which conveys said data stream, to generate a signal quality statistic determined from said communication signal and to formulate a command in response to said signal quality statistic;
• and
• a second transmitter located at said second site and configured to transmit said command so that said command can be received by said first receiver;
• wherein said first transmitter is further configured to adjust said quadrature balance signal in response to said command.

In a digital communication system, a method for ameliorating a bit error rate for a data stream transmitted from a first site to a second site, said method comprising:

• a) establishing a bi-directional communication link between said first and second sites;
• b) receiving a communication signal at said second site, said communication signal conveying said data stream;
• c) generating a signal quality statistic at said second site, said signal quality statistic being determined from said communication signal;
• d) formulating a command at said second site in response to said signal quality statistic;
• e) transmitting said command at said second site;
• f) receiving said command at said first site;
• g) adjusting, at said first site, a quadrature balance signal in response to said command, said quadrature balance signal altering one of first and second quadrature-phase signals relative to the other, said first and second quadrature-phase signals collectively conveying said data stream;
• h) combining said quadrature-phase signals at said first site to form said communication signal;
• i) transmitting said communication signal at said first site;
• and
• j) repeating said formulating step d), said transmitting step e), said receiving step f) and said adjusting step g) to adjust said quadrature balance signal until said signal quality statistic indicates a local optimum condition.