Use of antiphase signals for predistortion training within an amplifier system

A method of powering down an amplifier system having first and second amplification chains, wherein signal outputs of the first and second amplification chains are combined to produce an output transmission signal, the method comprising:

• (a) applying a first signal to the first amplification chain and a second signal to the second amplification chain, wherein the first and second signals are substantially in antiphase to inhibit emissions;
• (b) adaptively predistorting the first and second signals until a desired level of balance is reached between the first and second amplification chains;
• (c) decreasing amplification power levels of the first and second amplification chains by an incremental amount and repeating (b);
• (d) repeating (c) until a selected power level is reached.

A method of training an amplifier system having first and second amplification chains, wherein signal outputs of the first and second amplification chains are combined to produce an output transmission signal, the method comprising:

• (a) applying a first signal to the first amplification chain and a second signal to the second amplification chain, wherein the first and second signals fall within a first band, and are substantially in antiphase to inhibit emissions;
• (b) adaptively predistorting the first and second signals until a desired level of balance is reached between the first and second amplification chains;
• (c) increasing the bandwidth of the first and second signals and repeating (b);
• and
• (d) repeating (c) until the first and second signals have a bandwidth spanning a selected second band which encompasses the first band.

A method of changing an operational frequency of an amplifier system having first and second amplification chains, wherein outputs of the first and second amplification chains are combined to produce an output transmission signal, the method comprising:

• (a) applying a first signal to the first amplification chain and a second signal to the second amplification chain, wherein the first and second signals fall within a first band, and are substantially in antiphase to inhibit emissions;
• (b) adaptively predistorting the first and second signals until a desired level of balance is reached between the first and second amplification chains;
• (c) shifting the band of the first and second signals while maintaining said signals substantially in antiphase, and repeating (b);
• and
• (d) repeating (c) until a selected second band is reached.

A transmitter comprising:

• first and second amplification chains, each amplification chain including a digital compensation signal processor circuit which predistorts a respective signal passed therealong;
• an adaptive control processor which adaptively adjusts the digital compensation signal processor circuits to balance the first and second amplification chains;
• a combiner circuit coupled to outputs of the first and second amplification chains such that signals amplified along the first and second amplification chains are combined for transmission;
• and
• a signal generator circuit that applies training signals to the first and second amplification chains to train the digital compensation signal processor circuits during non-transmission events, wherein the training signals are in antiphase to inhibiting emissions.