Eaton Corporation

Easton Corporation

Jerome J Mikos

An amplitude-control system for a signal generator corrects for variations that occur in the amplitude of output signal upon changing of the specified frequency. It also corrects for errors that occur (due to non-linearity) in the amplitude of its output signal upon changing of the specified amplitude. The amplitude-control system performs both of the amplitude corrections simultaneously and very rapidly by means of an arrangement that employs mostly hardware and very little software. Look-up tables that are stored in memories are read directly instead of by a CPU, and a resulting control signal sets the gain of an amplifier that has voltage-controllable gain. The amplifier amplifies the uncorrected output of the signal generator so as to provide an output signal of corrected amplitude. Calibration is accomplished by automatically or semi-automatically by loading correction data into the memories to form look-up tables.

Amplitude-control system for a signal generator

An improved digital data synthesizer has a phase accumulator into which adjustable step increments are clocked. The output of the phase accumulator is connected to address a memory, in which a waveform function is digitally stored. Samples read from the memory at the successive addresses are converted to analog form and filtered to produce a final output signal of a desired frequency. Register stages of the phase accumulator are pipelined to increase their speed. The synthesizer has a plurality of digital-to-analog converters, all on a single chip to equalize the delay times occurring within them. A lookup memory permits a variety of output waveforms to be generated. Several lookup tables for the same waveform are stored with different phase spacing between addresses, and a decoder/addresser automatically selects the lookup table that has been found to result in best performance for a particular frequency. One or more correction lookup table can also be provided. The outputs of the main table and the correction table are combined to produce an analog signal of reduced distortion.

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Sylmar, CA, United States of America

Jerome J Mikos