Electronic musical instrument with 48-note keyboard - has digital programmed circuits to select the waveform of sounds produced

摘要

The sounds produced by the instrument can be radically altered by digital programming without the need for expensive analogue waveform shaping circuits. The keyboard switches are connected to an input register (1), which feeds a note ladder control circuit (2). The note ladder (3) is a 256-bit binary period counter, which feeds data to a decoder (4), and also back to the control unit. The decoded information is fed to a waveform programming section (5). The waveform information, which is digital form giving positive or negative values on a scale from 0 to 7, is fed to a multiplier (6), where it is multiplied by a signal from the volume curve counter (7). The multiplied signal is then fed, via a counter/accumulator loop (8,9), to a digital to analogue converter (10). The analogue output of the converter is fed to the loudspeaker (11).