| 摘要 |
A reference generator, providing a plurality of precisely-phased output signals, utilizes a microprocessor having a table of values for the output waveforms stored in a read-only memory thereof. The table entries include a multiplicity of values for providing a stepwise representation of each of the desired waveforms, which may have constant angular increments therebetween. The incremental tabular values are consecutively read responsive to the count in a timer, integral in the microcomputer, which is sequentially advanced by the pulse output of a voltage-to-frequency converter receiving a rate signal. The tabular values are converted to analog polyphase reference signals by a like number, equal to the number of phases, of digital-to-analog converters and associated low-pass filters. The output waveform peak amplitude is established by a dual-polarity reference voltage generator, responsive to a variable level signal. Essentially instantaneous reversal of the polyphase waveforms is provided by "angle complement" control of the present point utilized within the tables. The timer circuit provides steps of increasing size through the lookup-table to provide a gradual degradation in the number of steps in the output waveform when the rate signal exceeds the microcomputer execution speed upper limit.
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