Predistortion-based amplifier, transmitter and envelope detector

Abstract

A predistortion-based amplifier which compensates for distortions generated by the amplifier when a modulated wave signal is amplified thereby in accordance with a predistortion scheme, based on an envelope information of the modulated wave information. An envelope information detector for detecting information related to the envelope of the modulated signal to be amplified comprises, between an input terminal A 1 and an output terminal A 1, matching circuits 11, 14, diode circuits 12, 15, 16 for rectifying the modulated wave signal, a stub circuit 13 for removing a carrier component of the signal output from the diode circuits, and a signal converter circuit 17 for converting an envelope signal output from the stub circuit from a current signal to a voltage signal.

What is claimed is:  
     
         1 . An envelope detector for detecting information related to an envelop of a modulated wave signal, comprising: 
 a diode circuit for rectifying a modulated wave signal; and    a stub circuit for removing a carrier component of a signal output from said diode circuit.    
     
     
         2 . The envelope detector according to  claim 1 , wherein: 
 sais stub circuit includes a plurality of stub portions.    
     
     
         3 . The envelope detector according to  claim 1 , comprising: 
 a matching capacitor, a diode for rectifying a signal, an L-shaped microstrip line having a stub portion, a matching coil, an RF choke coil for biasing said diode, a voltage source for biasing said diode, and a resistor,    wherein an input terminal for receiving the modulated wave signal is connected to one end of said matching capacitor, the other end of which is connected to an anode of said diode, a cathode of said diode is connected to one end of one side of said L-shaped microstrip line, the other end of the one side of said L-shaped microstrip line is connected to an output terminal, a point between said input terminal and said matching capacitor is grounded through said matching coil, said biasing voltage source is connected between said matching capacitor and said diode through said RF choke coil, and a point between said microstrip line and said output terminal is grounded through said resistor.    
     
     
         4 . The envelope detector according to  claim 2 , comprising: 
 a matching capacitor, a diode for rectifying a signal, an inverted C-shaped microstrip line having two stub portions, a matching coil, an RF choke coil for biasing said diode, a voltage source for biasing said diode, and a resistor, wherein an input terminal for receiving the modulated wave signal is connected to one end of said matching capacitor, the other end of which is connected to an anode of said diode, a cathode of said diode is connected to one end of one side positioned between the remaining two sides of said inverted C-shaped microstrip line, the other end of the one side of said inverted C-shaped microstrip line is connected to an output terminal, a point between said input terminal and said matching capacitor is grounded through said matching coil, said biasing voltage source is connected between said matching capacitor and said diode through said RF choke coil, and a point between said microstrip line and said output terminal is grounded through said resistor.