| 摘要 |
A microcomputer based synthesizer having a digital keyboard, digital envelope generators, voltage controlled amplifiers and filters, and numerous potentiometer type presets is disclosed. The presets are scanned by the microcomputer, converted to digital form, stored for recall on demand in a non-volatile memory, converted to exponential form by use of a look-up table when required, and output to clamp-and-hold circuits associated with each voltage controlled circuit. Each preset sample and hold operation is followed by a scan of the keyboard to minimize the impact of the capture system on the keyboard scanning rate.
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