Abstract: The present invention provides a method and apparatus for compensating the output of a transmitter stage (50) of a communications system. A communications apparatus has a transmitter stage (50) providing a variable control voltage which varies the power of the transmitter stage. The impedance at the output of the transmitter stage. (50) varies as the power varies. A control generation circuit compares a reference voltage to the variable control voltage to produce a control signal (VvswrC). A compensated load (40) coupled to the output of the transmitter stage (50) has active component (s) whose' impedance varies in response to the control signal (VvsweC) so as to compensate for the impedance at the output of the transmitter stage (50).

Abstract: The present invention provides a method and apparatus for compensating the output of a transmitter stage (50) of a communications system. A communications apparatus has a transmitter stage (50) providing a variable control voltage which varies the power of the transmitter stage. The impedance at the output of the transmitter stage. (50) varies as the power varies. A control generation circuit compares a reference voltage to the variable control voltage to produce a control signal (VvswrC). A compensated load (40) coupled to the output of the transmitter stage (50) has active component (s) whose' impedance varies in response to the control signal (VvsweC) so as to compensate for the impedance at the output of the transmitter stage (50).

Abstract: The invention relates to a frequency converter designed for supplying an output signal having a radio frequency FR equal to the difference between the frequency FLO of a signal OS originating from an oscillator VCO and the frequency FI of an input signal IS. The frequency converter has two quadratic modules QM1 and QM2 for separating the signal originating from the-oscillator OS and the input signal IS into two components (LO1, LO2) and (FI1, FI2) in phase quadrature, two mixers MX1, and MX2 for multiplying the components thus obtained two-by-two, and combination means COMB for recombining the output signals RS1 and RS2 of the mixers MX1 and MX2. The frequency converter operates internally a good rejection of the image frequency while providing a good performance as regards noise and gain and an improved linearity as compared with known converters. Thus, frequency shifting before transmission in a wireless telephone may be accomplished.

Abstract: The invention relates to a frequency converter designed for supplying an output signal having a radio frequency FR equal to the difference between the frequency FLO of a signal OS originating from an oscillator VCO and the frequency FI of an input signal IS. According to the invention, such a frequency converter comprises: two quadratic modules QM1 and QM2 for separating the signal originating from the oscillator OS and the input signal IS into two components (LO1, LO2) and (FI1, FI2) in phase quadrature, two mixers MX1, and MX2 for multiplying the components thus obtained two-by-two, combination means COMB for recombining the output signals RS1 and RS2 of the mixers MX1 and MX2. The invention enables the frequency converter to operate internally a good rejection of the image frequency while providing a good performance as regards noise and gain and an improved linearity as compared with known converters.