Use of antiphase signals for predistortion training within an amplifier system
First Claim
1. A method of powering up 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 from an antenna;
(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 amplification power levels of the first and second amplification chains by an incremental amount and repeating (b); and
(d) repeating (c) until an operational power level is reached.
8 Assignments
0 Petitions
Accused Products
Abstract
A LINC amplifier of a radio frequency transmitter provides substantially linear amplification from two nonlinear amplifiers by decomposing the original signal into two constant amplitude envelope, phase varying signals, which, when combined, constructively and destructively interfere to re-form the original signal. The output of the LINC amplifier, which is to be transmitted via an antenna, is an amplified form of the original signal. The LINC amplifier uses a digital control mechanism to control and adapt a digital compensation network that directly compensates for the imperfections of the analog RF environment, including the amplifiers. The mechanism monitors the combined amplifier output and adjusts the signal components in order to precisely compensate for any differences in the characteristics of the separate signal paths which would cause the combination not to accurately represent the original signal. The mechanism also corrects the component signals using information which can be applied to the amplifiers independent of the signal to be transmitted.
-
Citations
28 Claims
-
1. A method of powering up 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 from an antenna;
(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 amplification power levels of the first and second amplification chains by an incremental amount and repeating (b); and
(d) repeating (c) until an operational power level is reached. - View Dependent Claims (2, 3, 4)
-
-
5. 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. - View Dependent Claims (6, 7, 8, 9)
-
-
10. 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. - View Dependent Claims (11, 12, 13)
-
-
14. 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. - View Dependent Claims (15, 16, 17)
-
-
18. 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. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
-
Specification