Signal processing circuit for a pointing device

A signal processing circuit for a pointing device including a detecting portion comprising first through fourth pressure detection elements responsive to a pressure applied to said detecting portion for producing first through fourth pressure detection signals, respectively, said signal processing circuit comprising processing means for processing said first through said fourth pressure detection signals into an X-axis movement value and a Y-axis movement value to move a cursor displayed on a display along an X-axis direction and a Y-axis direction, respectively, said first, said second, said third, and said fourth pressure detection elements being for defining the movement of said cursor in an X-axis plus direction, an X-axis minus direction, a Y-axis plus direction, and a Y-axis minus direction, respectively, said processing means comprising:

• first through fourth converting means for converting said first through said fourth pressure detection signals into first through fourth time signals representative of time values, respectively, each of said first through said fourth time signals comprising a succession of a plurality of frames for carrying said time values;
• a first processing circuit connected to said first converting means and supplied with said first time signal for correcting a particular time value in a particular frame of said first time signal with reference to a preceding time value in a preceding frame of said first time signal to produce a corrected value and for converting said corrected value into a cursor moving value in said X-axis plus direction to produce a first move signal;
• a second processing circuit connected to said second converting means and supplied with said second time signal for correcting a particular time value in a particular frame of said second time signal with reference to a preceding time value in a preceding frame of said second time signal to produce a corrected value and for converting said corrected value into a cursor moving value in said X-axis minus direction to produce a second move signal;
• a third processing circuit connected to said third converting means and supplied with said third time signal for correcting a particular time value in a particular frame of said third time signal with reference to a preceding time value in a preceding frame of said third time signal to produce a corrected value and for converting said corrected value into a cursor moving value in said Y-axis plus direction to produce a third move signal;
• a fourth processing circuit connected to said fourth converting means and supplied with said fourth time signal for correcting a particular time value in a particular frame of said fourth time signal with reference to a preceding time value in a preceding frame of said fourth time signal to produce a corrected value and for converting said corrected value into a cursor moving value in the Y-axis minus direction to produce a fourth move signal;
• a first calculation circuit connected to said first and said second processing circuits for carrying out a predetermined calculation by the use of said first and said second move signals to produce said X-axis movement value;
• and
• a second calculation circuit connected to said third and said fourth processing circuits for carrying out a predetermined calculation by the use of said third and said fourth move signals to produce said Y-axis movement value;
• wherein each of said first through said fourth processing circuits comprises:
• a signal converter for converting a particular time value in a particular frame into one of a plurality of types of cursor moving values with reference to a predetermined translation table;
• a representative value decision unit connected to said signal converter and supplied with said cursor moving for deciding a representative time value with reference to a predetermined translation curve related to said translation table;
• a multiplier connected to said representative value decision unit for multiplying said representative time value -1 to calculate a modified time value;
• a first adder connected to said multiplier for adding said modified time value and said particular time value in said particular frame to calculate a deviation time value;
• a delay circuit connected to said first adder for delaying said deviation time value by one frame to produce a delayed deviation time value;
• and
• a second adder connected to said delay circuit for adding said delayed deviation time value and a following time value in a following frame to calculate a corrected time value;
• said signal converter being for producing a cursor moving value in a following frame with reference to said predetermined translation table and on the basis of said corrected time value.