Radio communications device comprising at least one light source controlled by a digital signal

摘要

The device e.g. personal digital assistant, comprises of an LED (213) for indicating two distinct states of the device. Luminous intensity of the LED varies with different rhythm according to the states. The LED is controlled by a periodic digital signal from an integrator (60), in an active state. The integrator comprises of charging and discharging resistors (603, 604) and a capacitor (602).