Active ladder filter for voicing electronic musical instruments
AssigneeBaldwin Piano & Organ Company
InventorDale M. Uetrecht
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Abstract
A multiple-stage active RC distributed filter having multiple inputs and a single output for producing filtering of large groups of notes for tone coloration in electronic musical instruments. Output signals from the keying circuits may be applied to selected input stages of the filter through a resistor matrix to produce the desired tone coloration. Voicing may be further modified by one or more compensation networks at the filter output.
Claims6
A multiple input active ladder filter for voicing electronic musical instruments having one or more signal sources producing output signals of predetermined frequency, amplitude and phase, said filter comprising a plurality of cascaded active filter stages, each stage having a first input, a second input, and an output, said first input being connected to said output of a preceeding filter stage, each of said stages having a predetermined bandwidth and center frequency, and a resistor matrix for coupling the outputs of selected tone sources to selected second inputs of said filter stages, said matrix comprising a plurality of resistors, individual ones of said resistors connecting the output of a selected signal source with a plurality of selected second filter stage inputs, said stages operating to combine signals introduced at said second inputs.
In an electronic musical instrument having one or more tone sources, the improvement in combination therewith comprising a multiple input active ladder filter for filtering the output of one or more of said tone sources to produce desired tone coloration, said filter including a plurality of cascaded active filter stages, each stage having a first input, a second input, and an output, said first input being connected to said output of a preceding stage, each of said stages having a predetermined bandwidth and center frequency, and a resistor matrix for coupling the outputs of selected tone sources to selected second inputs of said filter stages, said matrix comprising a plurality of resistors, individual ones of said resistors connecting the output of a selected signal source with a plurality of selected sound filter stage inputs, said stages operating to combine signals introduced at said second inputs.
Dependencies are inferred from the claim text.