The ML6190B receives and detects standard low-frequency radio waves and outputs time codes indicating time and calendar information as digital signals. Using the time codes allows clocks built in various devices to be corrected automatically. The ML6190B is provided with a built-in antenna switch to allow reception of two radio frequencies. A CMOS amplifier circuit, which has extremely high impedance input, can capture antenna output signal voltage effectively, so it can have higher radio wave sensitivity than a bipolar amplifier ciucuit.