Anne M Graham

US Patent:

50038591, Apr 2, 1991

Filed:

Feb 16, 1989

Appl. No.:

7/311601

Inventors:

Charles Monte - Sepulueda CA
Paul J. White - Los Angeles CA
Anne C. Graham - Los Angeles CA

International Classification:

G10C 312

US Classification:

84423R

Abstract:

An improved percussive action electronic keyboard for play as a musical instrument of the type having pivoted playing keys having camming surfaces distal from finger contact surfaces thereof, pivoted hammers having cam follower surfaces for following the playing key camming surfaces, hammer stop for stopping the swing of the hammer in response to depression of its associated key, includes an electronic sensor for generating an electrical signal for each key which is related in amplitude to the pressure with which the key is depressed during play of the keyboard, and a scanning keyboard state monitor connected to said sensor including a keyboard scanner for scanning each of the keys of the keyboard to determine if a key event has occurred, an amplitude comparator for determining when a key depression causes a said key depression signal amplitude to pass predetermined minimum and maximum amplitude threshold values, a scan counter for counting the number of scans occurring between the scans when the key depression amplitude signal passes between the minimum and maximum amplitude threshold values and a digital output for putting out the number of scans as a digital value. A programmed microprocessor is connected to receive the digital value scan count for a key and converts the scan count into a key velocity signal.