Data recovery system for source synchronous data channels
AssigneeRedmere Technology Ltd.
InventorsJudith Ann Rea, Aidan Gerard Keady, John Anthony Keane, John Martin Horan
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Abstract
A high-definition multimedia interface (HDMI) receiver recovers high speed encoded data which are transmitted differentially over data channels of a lossy cable, along with a clock. Inter symbol interference, high-frequency loss, skew between the clock and data channels, and differential skew within a differential signal are compensated by analog circuits which are automatically tuned for best performance by observing the quality of the recovered analog signal. Oversampling is used to provide a 24-bit digital representation of the analog signal for determining the quality of the signal.
Claims19
A data recovery system for processing a high speed differential data signal and a clock signal into a digital signal, comprising:
- analog front end (AFE) circuitry having adjustable parameters for processing the differential data signal into a preprocessed data signal having reduced distortion;
- an oversampling circuit providing a digital representation of the preprocessed data signal;
- a training function circuit for estimating a quality of the digital representation of the preprocessed data signal, and adjusting the parameters of the AFE circuitry to improve the quality of the digital representation of the preprocessed data signal;
- and
- a bit extractor circuit for generating the digital signal from the digital representation of the preprocessed data signal;
- wherein the training function circuit further comprises:
- a digital circuit for estimating the quality of the preprocessed data signal and generating a Quality Number indicating said quality;
- an evaluation run control circuit for adjusting the parameters of AFE circuitry to a number of predetermined settings, and for monitoring a predetermined large number of the oversampled bits for each setting;
- a memory for retaining the best setting corresponding to the highest Quality Number;
- and
- a means for updating the parameters of the AFE circuitry to the best setting.
In a data recovery system having an analog front end (AFE) circuitry having adjustable parameters, a method of processing a high speed differential data signal and a clock signal into a digital signal, the method comprising the steps of:
- (a) processing the differential data signal into a preprocessed data signal having reduced distortion;
- (b) oversampling the preprocessed data signal to produce a digital representation of the preprocessed data signal;
- (c) estimating a quality of the digital representation of the preprocessed data signal;
- (d) adjusting the parameters of the AFE circuitry to improve the quality of the digital representation of the preprocessed data signal;
- and
- (e) generating the digital signal from the digital representation of the preprocessed data signal;
- wherein:
- the step (c) comprises generating a Quality Number indicating the quality of the digital representation of the preprocessed data signal;
- and
- the step (d) comprises adjusting the parameters of the AFE circuitry to a number of predetermined settings, and monitoring a predetermined large number of the oversampled bits for each setting.
Dependencies are inferred from the claim text.