Abstract: The present invention provides a filter circuit which can eliminate single noise effectively and is relatively simple in circuit configuration. First and second absolute values of differences between one-clock-preceding output data and both of one-clock-preceding input data and two-clock-preceding input data are respectively calculated by subtracters. When the first absolute value<the second absolute value, a selector selects one-clock-preceding input data as the present output data. When the first absolute value?the second absolute value, the selector selects two-clock-preceding input data as the present output data.

Abstract: A filter circuit removes noise from digital data which is successively input in synchronism with a sampling clock signal. The filter circuit serves to filter the digital data by calculating the average value of every two of the current, previous and twice previous values, determining one of the three average values that is closest to the previous filtered value at each time in synchronism with a sampling clock, outputting the current filtered value by performing an average operation on at least the closest one of the closest average value and previous filtered value. By this process, it is possible to effectively remove noise superimposed on consecutive samples, and also to make the waveform of the filtered output signal smooth.

Abstract: A semiconductor integrated device includes an internal oscillation circuit that oscillates to output a clock signal, a logic circuit, and a control circuit. In a normal operation mode, the logic circuit loads a target data signal in synchronization with the clock signal, and in a test mode, the logic circuit outputs a stop signal for stopping supply of the clock signal at a predetermined time, and allows the target data signal to be transferred to and from the outside after the stop signal is outputted. The control circuit controls such that, in the normal operation mode, the clock signal is supplied to the logic circuit, and in the test mode, the clock signal is not supplied to the logic circuit after the stop signal is outputted.

Abstract: The present invention provides a filter circuit which can eliminate single noise effectively and is relatively simple in circuit configuration. First and second absolute values of differences between one-clock-preceding output data and both of one-clock-preceding input data and two-clock-preceding input data are respectively calculated by subtracters. When the first absolute value<the second absolute value, a selector selects one-clock-preceding input data as the present output data. When the first absolute value?the second absolute value, the selector selects two-clock-preceding input data as the present output data.