Amplifier linearization by adaptive predistortion
US5049832A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 20, 1990 |
| Grant date | Sep 17, 1991 |
| Priority date | — |
| Expiry date | Apr 20, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2201/3233
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A method of linearizing an amplifier to produce an amplified output sample v.sub.a in response to a predistorted input sample v.sub.d derived from an input modulation sample v.sub.m, such that v.sub.a .perspectiveto.Kv.sub.m, where K is the amplifier's desired constant amplitude gain. The squared magnitude x.sub.m of the input modulation sample v.sub.m is first derived. A table entry F.sub.i is then selected from a table containing N.sub.t values F.sub.i where i=0, 1, . . . N.sub.t -1. Each table entry corresponds to a squared magnitude value x.sub.mi ; and, for each table entry, F.sub.i G(x.sub.mi .vertline.F.sub.i .vertline..sup.2).perspectiveto.K, where G(x) is the complex gain of the amplifier. The table entry selected is the one for which the absolute value .vertline.x.sub.m -x.sub.mi .vertline. is minimized with respect to the table index i. The predistorted sample v.sub.d is then derived, in rectangular coordinates, as v.sub.d =v.sub.m F.sub.i, viz: EQU Re(v.sub.d)=Re(v.sub.m)Re(F.sub.i)-Im(V.sub.m)Im(F.sub.i) EQU Im(v.sub.d)=Re(v.sub.m)Im(F.sub.i)+Im(V.sub.m)Re(F.sub.i) where Re(x) is the real component of x and Im(x) is the imaginary component of x.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.