Method for calibrating a frequency synthesiser using two-point modulation in a transceiver, the frequency synthesiser comprising: - a low-frequency or low-pass phase-locked loop, which comprises at least one phase comparator for comparing a reference signal (Ref) from a reference oscillator, and a modulation signal from a sigma-delta modulator, a charge pump connected to the output of the comparator, a loop filter connected to the output of the charge pump, a voltage-controlled oscillator VCO receiving an output signal from the loop filter, and generating a high frequency signal, and a programmable divider connected to the sigma-delta modulator and receiving the high frequency signal, and - a high frequency access with a digital-to-analogue converter DAC, which is connected to the voltage-controlled oscillator VCO of the phase-locked loop directly or via an adder, which performs the addition of the output signal from the loop filter, and the output signal from the digital-to-analogue converter, the calibration method being characterized in that it includes the following steps: - in a first phase of a calibration mode with the phase-locked loop closed, supplying a periodic excitation signal (Sd) at low frequency generated by a calibration unit of the transceiver to the sigma-delta modulator by deactivating the digital-to-analogue converter and transmitting the output signal from the loop filter via an IF filter of the transceiver followed by a VGA amplifier of the transceiver, where the IF filter and the VGA amplifier are used in normal operation in a reception mode of data signals from the transceiver to the calibration unit, which digitally converts an output signal from the VGA amplifier based on the signal from the loop filter, and offsetting the phase shift of this signal with respect to the excitation signal (Sd), and - in a second phase of the calibration mode with the phase-locked loop closed, supplying the periodic excitation signal (Sd) at low frequency to the sigma-delta modulator and to the activated digital-to-analogue converter, and calibrating the gain of the digital-to-analogue converter, by checking in the calibration unit, the sign or the polarity of the output signal from the loop filter with respect to the excitation signal (Sd), and using a dichotomy algorithm to adjust the gain. - a low-frequency or low-pass phase-locked loop, which comprises at least one phase comparator for comparing a reference signal (Ref) from a reference oscillator, and a modulation signal from a sigma-delta modulator, a charge pump connected to the output of the comparator, a loop filter connected to the output of the charge pump, a voltage-controlled oscillator VCO receiving an output signal from the loop filter, and generating a high frequency signal, and a programmable divider connected to the sigma-delta modulator and receiving the high frequency signal, and - a high frequency access with a digital-to-analogue converter DAC, which is connected to the voltage-controlled oscillator VCO of the phase-locked loop directly or via an adder, which performs the addition of the output signal from the loop filter, and the output signal from the digital-to-analogue converter, - in a first phase of a calibration mode with the phase-locked loop closed, supplying a periodic excitation signal (Sd) at low frequency generated by a calibration unit of the transceiver to the sigma-delta modulator by deactivating the digital-to-analogue converter and transmitting the output signal from the loop filter via an IF filter of the transceiver followed by a VGA amplifier of the transceiver, where the IF filter and the VGA amplifier are used in normal operation in a reception mode of data signals from the transceiver to the calibration unit, which digitally converts an output signal from the VGA amplifier based on the signal from the loop filter, and offsetting the phase shift of this signal with respect to the excitation signal (Sd), and - in a second phase of the calibration mode with the phase-locked loop closed, supplying the periodic excitation signal (Sd) at low frequency to the sigma-delta modulator and to the activated digital-to-analogue converter, and calibrating the gain of the digital-to-analogue converter, by checking in the calibration unit, the sign or the polarity of the output signal from the loop filter with respect to the excitation signal (Sd), and using a dichotomy algorithm to adjust the gain.