Variable attenuator

A variable attenuator comprising

• n attenuation resistor circuits and m adjustment resistor circuits connected in parallel to a signal line, wherein
• the n attenuation resistor circuits are on-off controlled by corresponding attenuation amount control signals,
• each of the n attenuation resistor circuits exhibits a different attenuation amount when being independently on-controlled,
• the adjustment resistor circuits correspond to k attenuation resistor circuits selected from the n attenuation resistor circuits, and are on-off controlled by a signal of a logical product of k attenuation amount control signals for performing on-off control corresponding to each of the selected k attenuation resistor circuits, and
• when being on-controlled by a signal of a logical product of the k attenuation amount control signals, attenuation amount of the adjustment resistor circuits are made equal to a sum of attenuation amounts when the k attenuation resistor circuits controlled by the corresponding k attenuation amount control signals are independently on-controlled together with a sum of attenuation amounts by the selected k attenuation resistor circuits simultaneously on-controlled by the corresponding k attenuation amount control signals.