Display interface systems and methods
AssigneeAnalog Devices, Inc.
InventorsRalph Moore, Michael Fernald
Life of this patent
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Abstract
Display interface embodiments are provided to capture various types of analog video signals and digitize them for presentation on advanced digital displays (e.g., computer displays and television displays). The embodiments include at least an error converter channel and a reference converter channel that can each amplify an analog input signal S with a fixed gain G and a programmed gain g and convert the amplified signal to a corresponding digital code. The embodiments also include a channel controller that is configured to conduct process steps that adjust the transfer function of the error converter channel to conform to (e.g., matches) the transfer function of the reference converter channel.
Claims20
A method of adjusting transfer functions of an error converter channel and a reference converter channel that can each amplify an analog input signal S with a fixed gain G and a programmed gain g and convert the amplified signal to a corresponding digital code, the method comprising the steps of:
- with a selected gain value of the programmed gain g, determining a first error parameter Err1 as ΔCerr/ΔCref wherein ΔCerr and ΔCref are code differences of said error converter channel and said reference converter channel that correspond to an analog input signal difference ΔS;
- with a selected signal value of said analog input signal S, determining a second error parameter Err2 as 2 [(Cerr2/Cerr1)/(Cref1/Cref2)]−1 wherein Cerr1 and Cerr2 are codes from said error converter channel and Cref1 and Cref2 are codes from said reference converter channel that respectively correspond to first and second programmed gains g1 and g2;
- forming first and second correction parameters α and β to respectively be 1/Err1Err2 and (1−Err1)/Err1Err2;
- and
- modifying the programmed gain of said error converter channel to be αg+β.
A method of adjusting transfer functions of an error converter channel and a reference converter channel that can each amplify an analog input signal S with a fixed gain G and a programmed gain g and convert the amplified signal to a corresponding digital code, the method comprising the steps of:
- assigning a value of substantially one to a selected one of a first error parameter Err1 and a second error parameter Err2;
- determining the other of said first error parameter Err1 and said second error parameter Err2 with a corresponding one of the following steps:
- a) with a selected gain value of the programmed gain g, determining said first error parameter Err1 as ΔCerr/ΔCref wherein ΔCerr and ΔCref are code differences of said error converter channel and said reference converter channel that correspond to an analog input signal difference ΔS;
- b) with a selected signal value of said analog input signal S, determining said second error parameter Err2 as 2 [(Cerr2/Cerr1)/(Cref1/Cref2)]−1 wherein Cerr1 and Cerr2 are codes from said error converter channel and Cref1 and Cref2 are codes from said reference converter channel that respectively correspond to first and second programmed gains g1 and g2;
- forming first and second correction parameters α and β to respectively be 1/Err1Err2 and (1−Err1)/Err1Err2;
- and
- modifying the programmed gain of said error converter channel to be αg+β.
A display interface, comprising:
- reference and error converter channels configured to each amplify an analog input signal S with a fixed gain G and a programmed gain g and convert the amplified signal to a corresponding digital code;
- reference and error multiplexers respectively coupled to said reference and error converter channels;
- and
- a channel controller configured to perform the steps of:
- assigning a value of substantially one to a selected one of a first error parameter Err1 and a second error parameter Err2;
- determining the other of said first error parameter Err1 and said second error parameter Err2 with a corresponding one of the following steps:
- a) with a selected gain value of the programmed gain g, determining said first error parameter Err1 as ΔCerr/ΔCref wherein ΔCerr and ΔCref are code differences of said error converter channel and said reference converter channel that correspond to an analog input signal difference ΔS that is provided through said reference and error multiplexers;
- b) with a selected signal value of said analog input signal S that is provided through said reference and error multiplexers, determining said second error parameter Err2 as 2 [(Cerr2/Cerr1)/(Cref1/Cref2)]−1 wherein Cerr1 and Cerr2 are codes from said error converter channel and Cref1 and Cref2 are codes from said reference converter channel that respectively correspond to first and second programmed gains g1 and g2;
- forming first and second correction parameters α and β to respectively be 1/Err1Err2 and (1−Err1)/Err1Err2;
- and
- modifying the programmed gain of said error converter channel to be αg+β.
Dependencies are inferred from the claim text.