Method and Device for Analong Digital Conversion of a Complex Signal

A conversion method for an analog-digital conversion device having two channels, I and Q respectively, in quadrature, each comprising an input and an associated output, for converting a complex analog input signal into a complex digital output signal by an analog-digital converter, each output being fed back onto said associated input so as to form a first and a second feedback loops each comprising a digital-analog converter, said device comprising a complex filter with a first stage and a last stage,

• said method comprising, on each of said channels, the steps consisting in:
• sampling an analog input signal;
• performing a signal integration of the sampled signal in said first stage of the filter in order to deliver an output signal from the first stage, said integration not introducing any substantial delay;
• performing a signal integration in the last stage of the filter in order to deliver an output signal from the last stage;
• introducing a substantial delay at the output of the last stage and converting the output signal from the last stage into a digital signal over several bits by said analog-digital converter;
• injecting said digital signal into the feedback loop of said channel;
• converting the digital signal into a feedback signal by said digital-analog converter;
• injecting said feedback signal into at least said first stage of said complex filter.