Voltage and resistance synthesizer using pulse width modulation
AssigneeFluke Corporation
InventorsLarry E. Eccleston, Daniel B. Carson
Life of this patent
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Abstract
A voltage and resistance synthesizer includes a pulse width modulator (PWM) for synthesizing voltage and resistance values at a pair of terminals. A selector switch selects between a resistance synthesis mode, in which resistance values are synthesized from a single reference resistor, and a voltage synthesis mode, in which voltage values are synthesized from a single reference voltage. The pulse width modulator permits digital control words to be received which govern the synthesized value with 16 bit resolution. A low pass filter blocks the switching frequency components and provides a d.c. voltage which is the product of the duty cycle and the reference value.
Claims6
A voltage and resistance synthesizer comprising:
- (a) a reference resistor coupled across an inverting amplifier for receiving a test current from an instrument to be calibrated to provide a first voltage;
- (b) a reference voltage source to provide a second voltage;
- (c) a switch coupled to said reference resistor and said reference voltage source for selecting one of said first and second voltage;
- (d) a PWM for modulating said selected one of said first and second voltages in accordance with a control signal having a controllable duty factor;, and
- (e) filter means coupled to said PWM to produce a d.c. voltage that is proportional to said duty factor.
Dependencies are inferred from the claim text.