Characterizing channel response based on composite gain determination

摘要

Based on tracked amplitude modulation (e.g., which may be hum modulation), compensation for amplitude modulation is applied across all orthogonal signal components of a non-time based orthogonal coded signal. Some examples of such non-time based orthogonal coded signals include an orthogonal frequency division multiplexing (OFDM) signal, a synchronous code division multiple access (S-CDMA) signal, or a code division multiple access (CDMA) signal, etc. The compensation may be applied to the signal across multiple frames, on a frame by frame basis, or intra-frame (i.e., changing and compensating differently within a frame). This compensation for amplitude modulation may be applied in conjunction with adaptive equalization in which different filter taps are applied to each respective orthogonal signal component of the signal. Also, automatic gain control (AGC) may be performed (e.g., before digital sampling) of a received signal in conjunction with the amplitude modulation compensation.

主权项

1. An apparatus comprising:
a front end module configured to receive a signal from a communication channel that is amplitude modulation affected, wherein the signal is a non-time based orthogonal coded signal having a plurality of orthogonal signal components; a gain adjustment module, coupled to the front end module, configured to use prediction, based on a tracked amplitude modulation within the signal, to compensate for amplitude modulation across all of the plurality of orthogonal signal components within a predetermined portion of the signal; a slicer module configured to process the signal output from the gain adjustment module to generate a plurality of hard decisions and a plurality of error terms; and an amplitude modulation detection module, coupled to the gain adjustment module, configured to employ at least one of the plurality of hard decisions and the plurality of error terms to track the amplitude modulation within the signal.