Transistor ratio controlled CMOS transmission line equalizer
AssigneeAdvanced Micro Devices, Inc.
InventorYi Cheng
Life of this patent
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Abstract
A CMOS transmission line equalizer is provided for receiving distorted signals transmitted through a transmission line and for compensating for the signal distortion. The equalizer has a transfer function characteristic with a single pole and a single zero. The transfer function includes a mirroring ratio circuit (CMR) for controlling the ratio between the single pole and the single zero. The mirroring ratio circuit is controlled by transistor size ratio. The single zero serves to cancel the dominant pole in the transfer function of the transmission line so as to compensate for the signal distortion caused by the transmission line.
Claims20
A CMOS transmission line equalizer for receiving distorted signals transmitted through a transmission line and for compensating for the signal distortion, said equalizer comprising:
- input means (24) for receiving the distorted signals transmitted through the transmission line, said transmission line having a transfer function with a dominant pole;
- transfer function means (H(S)) for generating a single pole and a single zero;
- said transfer function means including current mirroring ratio means (CMR) for controlling ratio between said single pole and said single zero, said current mirroring ratio means being formed of a plurality of transistors and being controlled by transistor size ratio;
- said single zero cancelling the dominant pole in the transfer function of said transmission line so as to compensate for the signal distortion caused by said transmission line;
- and
- output means (26) for generating restored signals which have been restored by said equalizer.
A communication system comprising in combination:
- transmitter means (14) for generating original signals;
- transmission medium means (18) for causing distortion in said original signals as they are transmitted therethrough;
- equalizer means (12) for receiving distorted signals transmitted through said transmission medium means and for compensating for the signal distortion;
- receiver means (22) for receiving restored signals from said equalizer means;
- and
- said equalizer means including, input means (24) for receiving the distorted signals transmitted through the transmission line, said transmission line having a transfer function with a dominant pole, transfer function means (H(S)) for generating a single pole and a single zero, said transfer function means including current mirroring ratio means (CMR) for controlling ratio between said single pole and said single zero, said current mirroring ratio means being formed of a plurality of transistors and being controlled by transistor size ratio, said single zero cancelling the dominant pole in the transfer function of said transmission line so as to compensate for the signal distortion caused by said transmission line, and output means (26) for generating restored signals which have been restored by said equalizer.
A CMOS transmission line equalizer for a communication system comprising:
- first transconductance means (G1) responsive to distorted signals transmitted through a transmission line for generating a first signal;
- first summer means (S1) responsive to said first signal and a second signal for generating a third signal;
- capacitance means (Z) responsive to said third signal for generating a fourth signal;
- second transconductance means (G2) responsive to said fourth signal for generating a fifth signal;
- third transconductance means (G3) also responsive to said fourth signal for generating said second signal;
- current mirroring ratio means (CMR) responsive to said fifth signal for generating a sixth signal;
- unity gain amplifier means (G4) also responsive to said third signal for generating a seventh signal;
- and
- second summer means (S2) responsive to said sixth and seventh signals for generating restored signals.
Dependencies are inferred from the claim text.