an interpolation circuit for use in an a / d converter comprises a first and a second pair of inputs and at least three pairs of outputs . the pairs of inputs receive pairs of two input signals which are substantially complementary to one another . at least two pairs of outputs supply pairs of two substantially complementary output signals . a first output of the third pair of outputs is coupled to a first input of the first pair of inputs . the second output of the third pair of outputs is connected to a circuit node which is not one of the inputs of the first pair of inputs . this node may be , for example , the first input of the second pair of inputs . another possibility is to make the node one end of an impedance element whose other end is coupled to the second input of the first pair of inputs .