Emc Technology, Inc.

David Markman

Joseph B Mazzochette

Robert J Blacka

A power sensing RF termination comprising a calibration means allows the user to correct for part-to-part variation, miss match loss and output offset. The power sensing RF termination comprises a first and second temperature sensitive resistors connected at a first common junction, a switching means for connecting either an RF input or a DC power reference to the first common junction, a first switch for connecting either a DC voltage source or a first current detecting resistor to the first temperature sensitive resistor, and a second current detecting resistor connected to the second temperature sensitive resistor. A first output terminal is connected to the junction between the first switch and the first temperature sensitive resistor. A second output terminal is connected to the first common junction. A third output terminal is connected to the junction between the second temperature sensitive resistor and the second current detecting resistor. The first and second temperature sensitive resistors have substantially the same temperature coefficient of resistance; but the first temperature sensitive resistor has a positive temperature coefficient of resistance while the second temperature sensitive resistor has a negative temperature coefficient of resistance. Using the measurements of the voltages at the first, second and third output terminals, a calibration table is formed correlating the power absorbed in the first and second temperature sensitive resistors to the ratio between the voltage drop across either the first or second temperature sensitive resistor and the voltage drop across both the first and second temperature resistive resistors.

Power sensing RF termination apparatus including temperature compensation means

A circuit for determining power changes in an RF circuit includes first and second temperature sensitive resistors connected in parallel with an RF input terminal so as to have a common junction therewith. The first resistor has a positive temperature coefficient of resistance and the second resistor has a negative temperature coefficient of resistance. A DC input terminal is connected to one of the temperature sensitive resistors and an output terminal is connected to the common junction of the two temperature sensitive resistors. Third and fourth temperature sensitive resistors have a common junction. The third resistor has a positive temperature coefficient of resistance and the fourth resistor has a negative temperature coefficient of resistance. The DC input terminal is also connected to one of the third and fourth temperature sensitive resistors, and an output terminal is connected to the common junction of the third and fourth temperature sensitive resistors. To improve the linearity of the circuit at high powers, each of the individual temperature sensitive resistors can be replaced with a pair of temperature sensitive resistors, one having a positive temperature coefficient of resistance and the other having a negative temperature coefficient of resistance. In such circuit four output terminals are provided with each output terminal being connected to the junction between the temperature sensitive resistors of each pair.

Termination for RF circuit which senses changes in power and which is

A temperature compensating voltage variable attenuator includes at least two temperature variable resistors. The temperature variable resistors have different temperature coefficients of resistance, preferably, with one temperature variable resistor having a positive temperature coefficient of resistance and the other temperature variable resistor having a negative temperature coefficient of resistance. The temperature coefficient of resistance of the temperature variable resistors being such that the attenuation of the attenuator varies with changes in temperature of the attenuator. A voltage variable heater resistor is adjacent both temperature variable resistors so that a change in the voltage applied to the heater resistor changes the temperature of the heater resistor. The heat from the heater resistor is applied to the temperature variable resistors so as to change the resistance of the temperature variable resistors. This provides a controlled change in the attenuation of the attenuator.

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Dresher, PA, United States of America

David Markman