A remote keyless entry (RKE) transponder has a noise alarm timer having a time interval used for determining whether a received signal meets a predefined condition within a time interval. If the received signal meets the predefined condition within the time interval, the noise alarm timer is disabled and the RKE transponder circuits are enabled so that normal operation in processing the desired signal commences. If the received signal does not meet the predefined condition within the time interval the noise alarm timer issues an alert signal, whereby appropriate action may be taken such as adjusting the channel input sensitivity, disabling a channel, or placing the RKE transponder into a sleep mode in order to reduce the power consumption caused by undesired input signals. A smart wake-up filter determines whether or not the input signal meets the predefined condition within the time interval.