Fully adaptive equalization for high loss communications channels
First Claim
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1. An equalization apparatus for automatically equalizing serial communication over a communication channel comprising:
- i) an adaptive transmit equalizer to receive an outgoing serial data stream and provide launch data into the communication channel, the launch data equalized in response to transmit control parameters;
ii) an adaptive receive equalizer to receive an incoming data stream from the communication channel and condition the received incoming data stream to produce an equalized output serial data stream in response to receive control parameters; and
iii) control means operable to control said adaptive transmit equalizer and said adaptive receive equalizer based on said incoming data stream;
wherein the adaptive receive equalizer includes an adaptive linear equalizer in combination with an adaptive non-linear decision feedback equalizer (DFE) to condition the received incoming data into said equalized output serial data stream; and
wherein the control means includes a data slicer providing input to a data demultiplexer, a positive offset monitor slicer providing input to a positive monitor demultiplexer and a negative offset monitor slicer providing input to a negative monitor demultiplexer, each slicer coupled to said equalized output serial data stream wherein the demultiplexers provide inputs for producing said transmit control parameters and said receive control parameters.
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Abstract
An equalization circuit is disclosed that enables high data rate transmission over high loss communications channels. Also disclosed is a set of functional blocks and update criteria that allow for the equalization function to be adapted for a large variety of different communications channels. A fully continuous adaptive equalizer is used in conjunction with a Decision Feedback Equalizer to fully equalize a large number of communications channels.
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Citations
21 Claims
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1. An equalization apparatus for automatically equalizing serial communication over a communication channel comprising:
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i) an adaptive transmit equalizer to receive an outgoing serial data stream and provide launch data into the communication channel, the launch data equalized in response to transmit control parameters; ii) an adaptive receive equalizer to receive an incoming data stream from the communication channel and condition the received incoming data stream to produce an equalized output serial data stream in response to receive control parameters; and iii) control means operable to control said adaptive transmit equalizer and said adaptive receive equalizer based on said incoming data stream; wherein the adaptive receive equalizer includes an adaptive linear equalizer in combination with an adaptive non-linear decision feedback equalizer (DFE) to condition the received incoming data into said equalized output serial data stream; and wherein the control means includes a data slicer providing input to a data demultiplexer, a positive offset monitor slicer providing input to a positive monitor demultiplexer and a negative offset monitor slicer providing input to a negative monitor demultiplexer, each slicer coupled to said equalized output serial data stream wherein the demultiplexers provide inputs for producing said transmit control parameters and said receive control parameters. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An equalization apparatus for automatically equalizing serial communication over a communication channel comprising:
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i) an adaptive transmit equalizer including a symbol spaced feed forward equalizer with a first tap to condition a cursor symbol corresponding to a tap parameter C0 and M additional taps to condition each successively earlier pre-cursor symbol corresponding to a respective tap parameter C−
M . . . C−
1 to receive an outgoing serial data stream and output launch data into the communication channel;ii) an adaptive receive equalizer to receive an incoming data stream from the communication channel including; a controllable filter including a high-pass filter coupled to a controllable pure gain stage to condition the received incoming data stream corresponding to a gain parameter GHF ; a summing node to sum the output of said controllable filter with the received incoming data stream that is gain adjusted corresponding to a gain parameter GDC; a controllable pure gain stage coupled to the output of said summing node to provide an output at a gain corresponding to a gain parameter GAGC; an N tap adaptive non-linear decision feedback equalizer (DFE) coupled to the output of the GAGC stage providing N symbol spaced taps, each of which can be programmed independently corresponding to a respective tap parameter C1, C2 . . . CN; and iii) a demux and tap update block controller coupled to the output of said adaptive receive equalizer to produce said gain and tap parameters GHF, GAGC and C−
1 , C0 . . . CN. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A method for automatically equalizing serial communication over a communication channel comprising the steps of:
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i) using an M tap feed forward equalizer to shape an outgoing data stream into a launch data stream based on a respective pre-cursor symbol tap parameter C−
M . . . C1−
and a symbol tap parameter C0;ii) supplying the launch data stream to the communication channel; iii) receiving an incoming data stream from the communication channel; iv) conditioning the received incoming data stream by passing the incoming data stream through an adaptive linear equalizer and an N Tap Decision Feedback Equalizer (DFE) with corresponding symbol spaced tap parameters [C−
M;
CN] to produce an equalized serial data stream;v) sampling the equalized serial data stream to latch user data; vi) sampling the equalized serial data stream to latch monitor data; and vii) producing the tap parameters [C−
M;
CN] from the user data and monitor data;further including a step of producing gain parameters GDC, GHF and GAGC from the user data and monitor data, and wherein the step of conditioning the received incoming data stream by passing the incoming data stream through an adaptive linear equalizer includes; i) supplying the incoming data stream to a first signal path through a high-pass filter coupled to a controllable pure gain stage at a gain corresponding to a gain parameter GHF and to a second signal path through a controllable pure gain stage coupled at a gain corresponding to a gain parameter GDC; ii) summing the outputs of said first and second signal paths; and iii) supplying the said sum of the outputs to a controllable pure gain stage at a gain corresponding to a gain parameter GAGC to produce the input for said an N Tap Decision Feedback Equalizer (DFE). - View Dependent Claims (19, 20, 21)
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Specification