Circuit for digitizing a sum of signals

The present invention relates to a circuit for digitizing a sum of at least one first input signal and a plurality of second input signals comprising - a passive adder circuit arranged for performing a summation of the second input signals and for outputting a summation signal, - a multi-bit quantizer circuit comprising a comparator arranged for comparing said summation signal applied at a first comparator input terminal with a signal applied at a second comparator input terminal, said signal being derived from the at least one first input signal and having an appropriate polarity so that the difference between the summation signal and said signal at the second comparator input terminal is indicative of the sum of the at least one first input signal and the plurality of second input signals, wherein the comparator is further arranged for producing a comparator output signal based on the sum of the at least one first input signal and the plurality of second input signals. The multi-bit quantizer circuit further comprises a control logic block for determining a multi-bit representation of the sum from the comparator output signal.