The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 17, 2017
Filed:
May. 05, 2015
Telefonaktiebolaget L M Ericsson (Publ), Stockholm, SE;
Torsten John Carlsson, Lund, SE;
Telefonaktiebolaget LM Ericsson (publ), Stockholm, SE;
Abstract
An envelope tracking RF transmitter calibration procedure calculates both a supply voltage to apply to a power amplifier for a modulated signal envelope to achieve ISO-gain, and a timing delay adjustment to time-align the applied supply voltage and the modulated signal to minimize distortion due to time delay error. An ISO-gain surface is calculated, as a function of the envelope of a modulated signal and the power amplifier supply voltage, for each of a plurality of desired gain values. As the envelope is swept through a predetermined range of values, demodulated outputs at predetermined points are sampled, and a set of non-linear functions relating the supply voltage to the envelope, which achieve the desired gain at the sampled points, are derived, using surface interpolation between the predetermined gain surface points. Data defining the functions are stored for use during transmitter operation. Distortion components in the transmitter output are detected, and are separated into even components representing time delay error distortion, and odd components representing transmitter saturation distortion. A timing delay value is calculated that minimizes the time delay error distortion.