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Improved D.C. offset estimation

A technology of offset estimation and phase shifter, which is applied in baseband systems, digital transmission systems, electrical components, etc., and can solve the problems of offset estimation that are difficult to solve and MRX requirements that are difficult to meet

Inactive Publication Date: 2012-10-17
ST ERICSSON SA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] Despite those and other previous attempts, the problem of d.c. offset estimation remains elusive, and the requirements for MRX remain elusive

Method used

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  • Improved D.C. offset estimation
  • Improved D.C. offset estimation
  • Improved D.C. offset estimation

Examples

Experimental program
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Embodiment Construction

[0023] The invention is applicable to any type of communication system and can be applied in any part of the system where d.c. offset estimation is concerned, eg uplink (UL) or downlink (DL).

[0024] Figure 2A , Figure 2B and Figure 2C is a block diagram of part of a transmitter 200 with a measurement receiver modified according to the invention. Transmitter 200 includes a coupler 202 , a transmit path having an analog portion 204 and a digital portion 206 , a voltage controlled oscillator (VCO) 208 , a phase shifter 210 , an MRX 212 and an offset estimator 214 . As explained in more detail below, Figure 2B and Figure 2C The phase shifter 210 in the ratio Figure 2A The phase shifter 210 in is more generalized. For example, Figure 2C The phase shifter 210 is shown split into separate sections 210-1, 210-2, the separate VCOs 208-1, 208-2 driving the separate sections 210-1, 210-2. However, usually in Figure 2A , Figure 2B and Figure 2C The portions of the e...

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PUM

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Abstract

A combination of a phase shifter, a measurement receiver, and an offset estimator enable the D.C. offset in the transmit path of a quadrature transmitter to be distinguished from the D.C. offset in the measurement receiver. The measurement receiver performs a first measurement on the transmit path output with a "normal" phase shift of 0 degrees and 90 degrees for in-phase (I) and quadrature (Q) components, and a second measurement with a "special" phase shift for the I and Q components. In one embodiment, the "special" phase shift for the I and Q components is 180 degrees and 270 degrees, respectively.

Description

technical field [0001] This invention relates to electronic communication systems, and more particularly to signal offset compensation in such systems. Background technique [0002] Many existing electronic communication systems use quadrature modulation schemes that use in-phase (I) and quadrature (Q) signal components and do not have a constant envelope. Examples of such communication systems are cellular radiotelephone systems using Wideband Code Division Multiple Access (WCDMA), Orthogonal Frequency Division Multiple Access (OFDMA) and variations thereof. Thus, part of the communication information is encoded in the amplitude (envelope) of the transmitted signal and part of the communication information is encoded in the phase of the transmitted signal. [0003] To avoid distorting the communicated information, the power amplifier (PA) and various other components of the wireless transmitter must be linear, that is, for all possible power levels, the relationship betwee...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B1/04H04B1/30H04L27/36
CPCH04L2027/0016H04L27/2647H04B1/302H04B1/0475H04L27/364H04L25/061
Inventor 乔纳斯·佩尔松斯文·马蒂松
Owner ST ERICSSON SA