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Channel state aided automatic gain control

A channel gain and channel state technology, applied in the direction of gain control, amplification control, transmission control/equalization, etc.

Active Publication Date: 2007-12-12
SEAGATE TECH LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For example, in a magnetic recording channel, the playback signal level may vary by more than 20dB due to the combined characteristics of the head, media, and preamplifier

Method used

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  • Channel state aided automatic gain control
  • Channel state aided automatic gain control
  • Channel state aided automatic gain control

Examples

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Embodiment Construction

[0028] Referring to the drawings, FIG. 1 is a schematic diagram of a communication system 10 with a data-assisted AGC 12 . signal of interest k With variable gain λ, channel response h c and additive noise n on the transmission channel 14. This transforms the signal of interest into a signal r received by the controllable amplifier circuit 16 with a gain factor g. The gain-controlled signal d is output by the amplifier and passed to the detector 18, which produces an estimate of the signal of interest  k . This estimate is obtained by having the response h c The feedback circuit 20 to produce an estimated ideal signal The estimated ideal signal The sum signal d is combined at a summing junction 22 to produce an error signal e for controlling the AGC amplifier. The automatic gain control unit uses this error signal e, the ideal signal The gain coefficient g of the amplifier is adapted to the difference between the gain-controlled signal d. In theory, once the loop ...

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Abstract

An apparatus comprises a circuit for producing a channel gain control signal, and an amplifier for amplifying a signal of interest in response to the channel gain control signal, wherein the channel gain control signal is generated from a channel state signal that is not derived from the signal of interest.

Description

technical field [0001] This paper relates to automatic gain control (AGC) for channel receivers, and in particular to AGC using a priori channel state information. Background technique [0002] In many communication systems, the amplitude of the received signal varies widely. For example, in a magnetic recording channel, playback signal levels may vary by more than 20 dB due to the combined characteristics of the head, media, and preamplifier. In such situations, automatic gain control (AGC) is commonly used to limit signal variations. The signal level after AGC becomes more consistent with a much smaller dynamic range, which facilitates further signal processing. [0003] There are mainly two different automatic gain control methods - non-data-assisted (NDA) methods or data-assisted (DA) methods, depending on whether decisions about the transmitted symbols are utilized. In general, data-aided AGC is more efficient than non-data-aided AGC, so data-aided AGC is more common...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B7/005
CPCH03G3/3052
Inventor 杨学士
Owner SEAGATE TECH LLC