Abstract: An electronic monitoring system with a sleep mode includes an access point having a first clock circuit and at least one monitoring device. The monitoring device obtains images of a monitored area and generates a trigger signal corresponding to a detected event. The monitoring device includes a second clock circuit and first and second control architectures. The first control architecture obtains the images of the monitored area and to enters an idle state. The second control architecture receives the trigger signal and wakes the first control architecture from the idle state. Upon waking from the idle state, the control architectures determine a present time for the first control architecture as a function of stored times for the first and second control architectures and of the present time in the second control architecture. A method of providing a high precision time stamp upon waking from the sleep mode also is disclosed.