Claims
- 1. A keyboard system for use in an electronic keyboard musical instrument comprising:
- a key actuatable from a rest position to a nominally fully depressed reference position,
- key output means connected to said key for producing an actual key output signal which varies as a function of the distance which the key is depressed,
- keydown trigger means operatively connected to said key output means for generating a keydown trigger signal responsive to an expected reference value of the key output signal corresponding to the key nominally fully depressed reference position,
- calibrate means responsive in a calibrate mode of the keyboard system to the key reaching the nominally fully depressed position for generating and storing an offset value relating to the differnece between the expected reference value of the key output signal and the actual key output signal value produced when the key reaches the nominally fully depressed reference position, and
- offset means responsive to said keydown trigger means in an operate mode of the keyboard system for retrieving and combining the offset value with the actual value of the key output signal to convert the actual value to the expected value when the key reaches the nominally fully depressed reference position thereby to compensate for irregularities in the key or key output means.
- 2. The keyboard system of claim 1 wherein said key output means includes an analog to digital converter means connected to said key for generating a digital number corresponding to the actual output signal, and said offset means includes an adder means having one input connected to said analog to digital converter means to receive the digital number and another input connected to said calibrate means to receive the retrieved offset value, said adder means combining the offset value and digital number to produce said expected value.
- 3. The keyboard system of claim 1 wherein said key is further depressible beyond the reference position, and including means responsive to such further depression and to the actual key output signal for generating a signal indicative of the velocity with which the key is depressed based on the amount of travel of the key past the reference position.
- 4. The keyboard system of claim 3 including a resilient stop means contacted by said key for yieldably limiting the movement of said key past the reference position, the reference position being about the position of the key when the key contacts the resilient stop means.
- 5. The keyboard system of claim 4 wherein said key output means comprises an electrode connected to the key and moveable in an electrostatic field by said key, the electrostatic field impressing on said key a voltage varying with the position of the electrode in the field.
- 6. The keyboard system of claim 1 wherein said key is further depressible beyond the reference position, and said key output means produces an actual key output signal corresponding to the amount of further depression of the key past the reference position, and including control means for combining the offset value and actual key output signal corresponding to such further depression to generate a control signal bearing a relation to said expected reference value corresponding to the amount of key depression beyond the reference position.
- 7. The keyboard system of claim 6 wherein said control means includes an adder means for adding together the offset value and key output signal to produce the control signal.
- 8. A keyboard system comprising:
- a key actuatable from a rest position to a nominally fully depressed reference position, the reference position being determined by mechanical resistance to the key,
- key output means connected to said key for producing an actual key output signal which varies as a function of the distance which the key is depressed,
- keydown trigger means operatively connected to said key output means for generating a keydown trigger signal responsive to an expected reference signal corresponsing to the key nominally depressed reference position, the actual value of the key output signal being capable of differing from the expected reference value depending on key and output means irregularities,
- calibrate means responsive in a calibrate mode of the keyboard system to the key reaching the nominally fully depressed position for generating and storing an offset value relating to the difference between the expected reference signal and the actual key output signal value produced when the key reaches the nominally fully depressed reference position, and
- offset means responsive in an operate mode of the keyboard system for retrieving the offset value and being responsive to the key output signal and offset signal for producing said reference signal when the key reaches the nominally depressed reference position.
- 9. The keyboard system of claim 8 wherein said key is further depressible beyond the reference position, and said key output means produces actual key output signals corresponding to the amount of further depression of the key past the reference position, and including control means responsive to the actual key output signal corresponding to such further derpession and to the offset value to generate a control signal bearing a relation to said expected reference signal corresponding to the amount of key depression beyond the reference position.
- 10. The keyboard system of claim 9 including a resilient stop means contacted by said key for yieldably limiting the movement of said key past the reference position, the reference position being about the position of the key when the key contacts the resilient step means.
- 11. The keyboard system of claim 10 wherein said key output means comprises an electrode connected to the key and moveable in an electrostatic field by said key, the electrostatic field impressing on said key a voltage varying with the position of the electrode in the field.
- 12. A keyboard system comprising:
- a key actuable from a rest position to a reference position,
- key output means for producing a digital key output signal which varies as a function of the distance which the key is depressed,
- memory means for storing a digital offset value for said key,
- keydown trigger means operatively connected to said key output means for generating a keydown trigger signal responsive to an expected reference value of the key output signal corresponding to the reference position,
- adder means connected to the output of said key output means for adding to the digital key output signal the offset value stored in said memory to thereby produce a second digital output signal, and
- calibrate means responsive in a calibrate mode for sensing when said key is in said reference position for storing in said memory means the offset value relating to the difference between the expected reference value and the actual key output signal when the key is in the reference position.
- 13. The keyboard system of claim 12 wherein said memory means includes a random access memory and means for producing the complement of an output from the random access memory.
- 14. The method of playing and calibrating a keyboard system having a key actuatable fron a rest position to a nominally depressed reference position comprising:
- depressing the key and producing an actual key output signal that varies as a function of the distance of depression of the key,
- calibrating the system by depressing the key to the reference position and storing an offset value equal to the difference between the actual key output signal at the reference position to the key and an expected reference value of the key output signal at the reference position, and
- when the system is in an operate mode, combining the offset value with the actual key output signal to produce a calibrated resultant signal corresponding to the position of the key normalized to the reference position.
CROSS REFERENCE TO RELATED APPLICATIONS
This is a continuation in part of application Ser. No. 577,854, filed Feb. 7, 1984, and now U.S. Pat. No. 4,558,623.
US Referenced Citations (12)
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
577854 |
Feb 1984 |
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