Sensitivity coding circuit for an electronic instrument
AssigneeHewlett-Packard Company
InventorAllen P. Edwards
Life of this patent
Estimating the term…
Abstract
A power meter having a remote power transducer is provided with a circuit for measuring the value of a resistor in the transducer to indicate and automatically adjust the power measuring circuitry for the sensitivity of the transducer used.
Claims5
A transducer sensitivity coding circuit for an electronic instrument having measurement circuits and a remote transducer unit connected to the electronic instrument by a cable, the electronic instrument employing different transducers for different measurement ranges, the transducer sensitivity coding circuit automatically providing information to the electronic instrument of the transducer sensitivity comprising:
- a fixed value resistor mounted in the transducer unit having a value indicative of the sensitivity of a particular transducer unit;
- a current supply circuit in the electronic instrument connected to the cable for supplying a current to the resistor to develop a resistor voltage across the resistor;
- and
- comparator means in the electronic instrument, connected to the cable and the measurement circuits, for comparing the resistor voltage with a plurality of reference voltages for producing a signal indicative of the value of the resistor in the transducer unit to adjust the sensitivity of the measurement circuits.
Dependencies are inferred from the claim text.