Patent ID: 7257384
Filing Date: 2007-08-14
Classification: H03C,H03F

Abstract:
1. A method for detecting an envelope of an RF signal being input to an RF transistor wherein whenever the RF transistor is a FET having a grounded source or a bipolar transistor having a grounded emitter, wherein the output signal is obtained by performing the following steps: a) providing said RF transistor operating essentially at a non-linear operating point at the RF frequency range, said RF transistor being fed by a DC power supply through an RF filter and terminated by a dummy load for RF components in an output signal of said RF transistor; b) feeding said RF signal into the input of said RF transistor: c) obtaining an output signal representing said envelope from the fluctuating output current drawn by said RF transistor from said DC power supply during a time period when said RF signal is applied to said input: d) connecting a first contact of an RF filter to one of a drain of said FET or to a collector of said bipolar transistor; e) connecting a more negative contact of the DC power supply to ground: f) connecting a more positive contact of said DC power supply to a second contact of said RF filter through an impedance; and g) coupling the voltage developed across said impedance by a coupling capacitor, thereby determining the polarity of the output signal to be opposite to the polarity of said DC power supply; wherein the output signal is obtained by filtering out the RF components from the fluctuating current, thereby obtaining the mean detected current, being monotonically related to the envelope of the RF signal.