Patent ID: 7405684

Claim:
A signal selecting circuit outputting a first and a second digital signals by convening a first and a second analog signals into digital signals, the first and the second analog signals being the same or different signals selected from a plurality of analog signals, the signal selecting circuit comprising: an analog signal selection circuit that, based on an analog selection signal, selects the first and the second analog signals from the plurality of analog signals; a first AD converter that converts the first analog signal outputted from the analog signal selection circuit into a third digital signal to output the third digital signal; a second AD converter that converts the second analog signal outputted from the analog signal selection circuit into a fourth digital signal to output the fourth digital signal; a digital signal selection circuit that, based on a digital selection signal, selectively outputs one or both of the third and the fourth digital signals as the first and the second digital signals; and a control circuit that, based on an output selection signal for selecting the first and the second digital signals, outputs the analog selection signal and the digital selection signal, wherein when the control circuit receives the output selection signal for changing the second digital signal to the same signal as the first digital signal, in a state where the third digital signal is outputted as the first digital signal and where the fourth digital signal is outputted as the second digital signal, the control circuit outputs the digital selection signal for outputting the third digital signal as the first and the second digital signals.