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Distortion compensation apparatus

A distortion compensation and predistortion technology, which is applied to the components of the amplifying device, the adaptive predistortion of the look-up table, and the improvement of the amplifier to reduce nonlinear distortion, etc., and can solve problems such as enlargement

Inactive Publication Date: 2006-09-13
FUJITSU LTD
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Problems solved by technology

[0041] In this way, when the number of carriers (transmission bandwidth) is variable, distortion compensation conversely produces increased unwanted waves (inconsistent with the standard for unwanted waves)

Method used

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Embodiment Construction

[0056] Hereinafter, preferred embodiments of the present invention will be described with reference to the diagrams and drawings. However, it should be noted that these embodiments are provided for ease of understanding, and therefore the technical scope of the present invention cannot be limited to the embodiments described below.

[0057] Figure 8 It is a block diagram of a transmitter having a digital nonlinear distortion compensation function to which the present invention is applied. exist Figure 8 , the same designation indicates Figure 4 and 5 The same functional parts shown in the

[0058] exist Figure 8 Among them, as a structural example, the distortion compensation coefficient memory 90 includes a look-up table (LUT), which is accessed by using the input signal power value obtained in the power calculator 15d as an address.

[0059] The distortion compensation coefficient calculator 92 is used to obtain the distortion compensation coefficient to be stored ...

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Abstract

Provided is a distortion compensation apparatus which can correspond to the number of carriers adaptively. The apparatus includes a distortion compensation processing circuit multiplying an input signal by a distortion compensation coefficient; a distortion compensation coefficient storage storing the distortion compensation coefficient correspondingly to the input signal power; a distortion compensation coefficient calculator calculating an update value of the distortion compensation coefficient stored in the distortion compensation coefficient storage, based on the input signal and a feedback signal being feedbacked from the output side of a distortion device; a digital filter inputting the output of the distortion compensation processing circuit. Further is included a modifying unit, which modifies the passband of the digital filter so as to reduce a distortion compensation control bandwidth in the predistortion portion, in response to the reduction of the number of carriers in the input signal.

Description

technical field [0001] The present invention relates to a distortion compensation device, and more particularly to a distortion compensation device, which can obtain a differential signal between a reference signal (that is, a transmission signal) and a feedback signal; use an adaptive algorithm to calculate the distortion compensation coefficient to reduce A differential signal; using the calculated distortion compensation coefficient to update the stored distortion compensation coefficient; and performing distortion compensation on the transmitted signal based on the obtained distortion compensation coefficient. Background technique [0002] In recent years, high-efficiency digital transmission has been employed in radio communications. When multilevel phase modulation is employed in radio communication, an important technique is to suppress nonlinear distortion by linearizing the amplification characteristics of a power amplifier on the transmission side, thereby reducing...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B1/04H03F1/32H04L27/36
CPCH03F1/3247H03F2201/3233H04B2001/0425H03F1/3258H03F1/0205H03F1/3241
Inventor 佐佐木孝朗大贯政幸宫本洋巳
Owner FUJITSU LTD
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