Circuit for Detecting the Impedance of a Load
AssigneeKoninklijke Philips Electronics N.V.
InventorsAdrianus Van Bezooijen, Christophe Chanlo
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Abstract
The invention refers to a circuit and a method for detecting the impedance of a load, whereby the circuit and the method can be used by an impedance matching circuit. Impedance matching circuits need a complex algorithm to adjust the impedance accordingly. This algorithm renders the response time to be long. It has been found out that the complexity partially stems from the fact that the phase of the reflection coefficient is not known over the full range of 0° to 360°. A quadrature phase detector is used to provide the full phase information.
Claims12
Circuit for detecting the impedance or the admittance of a load, comprising:
- a) a directional coupler having input terminals being connectable to a radio frequency amplifier and being connectable to the load,
- b) the directional coupler having output terminals being connected to
- b1) first means for measuring the magnitude of the voltage or the magnitude of the current of the forward wave,
- b2) second means for measuring the magnitude of the voltage or the magnitude of the current of the reflected wave,
- b3) a quadrature phase detector being arranged to output signals providing information on the phase θ of the reflection coefficient Γ within a range of 0° to 360°.
Method for detecting the impedance or the admittance of a load, the method comprising the following steps:
- a) arranging a directional coupler between a radio frequency amplifier and a load
- b) arranging the output of a forward wave by the RF amplifier the forward wave travelling towards the load
- c) measuring the magnitude of the voltage or the magnitude of the current of the forward wave,
- d) measuring the magnitude of the voltage or the magnitude of the current of the reflected wave,
- e) measuring the phase θ of the reflection coefficient Γ within a range of 0° to 360°.
Dependencies are inferred from the claim text.