Adaptable raster distortion correction system for multiple horizontal scanning frequencies

A distortion correction system, comprising:

• means for storing distortion correction values;
• a digital filter for processing said distortion correction values;
• said digital filter supplying said distortion correction values together with a first number of interpolated distortion correction values in a first operating mode;
• said digital filter supplying said distortion correction values together with a second number of interpolated distortion correction values in a second operating mode;
• a digital to analog converter for converting said supplied distortion correction values to an analog distortion correction signal;
• an analog low pass filter coupled for receiving said analog distortion correction signal in each of said operating modes and generating an analog deflection signal;
• means for determining a horizontal scanning frequency of an input video signal;
• and,
• control means responsive to said determining means for selecting one of said operating modes for different horizontal scanning rates.

A distortion correction system, comprising:

• means for supplying different numbers of digital distortion correction values;
• a digital to analog converter for converting said supplied distortion correction values to an analog distortion correction signal;
• an analog low pass filter coupled for receiving said analog distortion correction signal and generating an analog deflection signal, said low pass filter being optimized only for those of said analog deflection signals having a given sample rate;
• means for determining a horizontal scanning frequency of an input video signal;
• and,
• control means responsive to said determining means for varying said different numbers of said supplied distortion correction values to maintain said given sample rate of said analog deflection signal for different horizontal scanning rates.

A method for distortion correction, comprising the steps of:

• storing digital distortion correction values;
• digitally filtering said digital-distortion correction values in a first mode of operation to generate interpolated distortion correction values;
• supplying as an output said distortion correction values together with said interpolated distortion correction values in said first mode of operation;
• supplying only said distortion correction values as said output in a second mode of operation;
• converting said supplied output to an analog distortion correction signal;
• low pass filtering said analog distortion correction signal in each of said operating modes with the same passive analog filter, for generating an analog deflection signal;
• determining a horizontal scanning frequency of an input video signal;
• and,
• responsive to said determining step, selecting one of said operating modes for different horizontal scanning frequencies.

A method for distortion correction, comprising the steps of:

• storing digital distortion correction values;
• digitally filtering said digital distortion correction values in a first mode of operation to generate a first number of interpolated distortion correction values;
• supplying as an output said distortion correction values together with said first number of interpolated distortion correction values in said first mode of operation;
• digitally filtering said digital distortion correction values in a second mode of operation to generate a second number of interpolated distortion correction values;
• supplying as said output said distortion correction values together with said second number of interpolated distortion correction values in said second mode of operation;
• converting said supplied output to an analog distortion correction signal;
• low pass filtering said analog distortion correction signal in each of said operating modes with the same passive analog filter for generating an analog deflection signal;
• determining a horizontal scanning frequency of an input video signal;
• and,
• responsive to said determining step, selecting one of said operating modes for different horizontal scanning frequencies.

A method for distortion correction, comprising the steps of:

• supplying different numbers of digital distortion correction values;
• converting said supplied digital distortion correction values to an analog distortion correction signal;
• analog low pass filtering said analog distortion correction signal with a characteristic response optimized only for those of said analog deflection signals having a given sample rate;
• determining a horizontal scanning frequency of an input video signal;
• and,
• varying said different numbers of said supplied distortion correction values to maintain said given sample rate of said analog deflection signal for different horizontal scanning rates.