Digital automatic gain control

An automatic gain controller operating on a signal quadrature modulated communication, having amplitude modulated and phase modulated components, comprising: a logarithmic detector (34) to determine the logarithms of the amplitudes of the quadrature modulated signal, and a first analog-digital converter (38) to convert the logarithms of the amplitudes into digital values ​​of the logs; the controller being characterized by comprising: a limiting amplifier (32) receiving the signal quadrature modulated communication and limiting the signal quadrature modulated communication, to generate a signal which is positive or negative representing relative phase, and having a pulse length representing phase information an I and Q demodulator (50) for demodulating the signal generated by the limiting amplifier (32) in I and Q components; I an analog-digital (52) converter for converting the demodulated I components into digital values ​​of the I components representing phase information of a part I of the quadrature modulated signal; and Q analog to digital converter (54) for converting the demodulated Q components into digital values ​​of the Q component representing phase information of a Q portion of the quadrature modulated signal.