RF receiver

A RF transmitter comprising:

• a phase-locked loop, comprising an oscillator arranged to output an oscillator carrier,
• a power amplifier, arranged to conduct a power amplifier current,
• a phase shifter module between the phase-locked loop and the power amplifier, arranged to introduce a phase shift between the oscillator carrier and a harmonic of the power amplifier current, in order reduce a frequency shift of the oscillator carrier due to pushing and/or pulling,
• a computing unit, and
• an oscillator frequency shift measurement unit,
• wherein:
• the power amplifier is arranged to be ramped-up during a calibration phase,
• the phase shifter module is arranged so that during this calibration phase, the variable phase shift takes different values,
• the measurement unit is arranged to measure the oscillator frequency shift against a load power for each value of the phase shift,
• the computing unit is arranged to select the value of the phase shift minimizing a peak-peak oscillator frequency shift against the load power,
• the measurement unit is the phase-locked loop and comprises a phase detector module and an additional module connected to an output of the phase detector module,
• the additional module is arranged so as to compute the oscillator frequency shift,
• the phase shifter module comprises several selectable delay cells, each delay cell comprising several inverters, and
• a control module comprises:
• a temperature sensor, and
• a potentiometer comprising a p-output and a n-output,
• wherein the temperature sensor is arranged to control the n-output and the p-output, and the n-output and the p-output is arranged to control fourth terminals of N-type and P-type transistors of the several inverters, respectively.