Adaptive strum keying for a keyboard electronic musical instrument

In combination with a keyboard operated electronic musical instrument having keying means comprising an array of keyswitches operable between actuated and released states and having a number of tone generators assigned to actuated keyswitches, apparatus for imitating a strummed stringed musical instrument comprising;

• a detection means responsive to operable states of said array of keyswitches wherein a switch data value is generated corresponding to each keyswitch operated in an actuated state,
• a status memory for storing said switch data values,
• a chord detect means, responsive to the switch data values stored in said status memory, comprising a matched filter processor wherein a musical chord type is selected from a preselected set of musical chord types irrespectively of whether or not said stored switch data values correspond to a musical chord type,
• a root note detect means, responsive to the switch data values stored in said status memory, for selecting a chord root note corresponding to said selected musical chord type,
• an interval measuring means responsive to the switch data values generated by said detection means, whereby a time interval number is generated corresponding to the elapsed time between successive actuated state of the keyswitches in said array of keyswitches,
• an interval detection means responsive to said time interval number wherein a plurality of control signals are generated,
• a strum generation means, responsive to said pluarlity of control signals, wherein a sequence of strum keying signals is generated,
• a note data generator means responsive to said selected chord type and said selected chord root note wherein input note data is generated,
• a plurality of tone generators operable at frequencies responsive to said input note data,
• a strum keying means, responsive to said strum keying signals, for selectively providing said input note data to said plurality of tone generators thereby imitating said strummed stringed musical instrument.