Abstract: This design idea explains how a 915MHz receiver can sound an alarm when a transmitter moves beyond a predetermined boundary. Maxim > Design Support > App Notes > Amplifier and Comparator Circuits > APP 5099 Maxim > Design Support > App Notes > Oscillators/Delay Lines/Timers/Counters > APP 5099 Maxim > Design Support > App Notes > Wireless and RF > APP 5099 Keywords: transmitter, RF, receiver, alarm, RF perimeter Aug 02, 2011 APPLICATION NOTE 5099 Alarm Sounds When RF Transmitter is Out of Range By: Tom Au-Yeung Craig Sakamoto Abstract: This design idea explains how a 915MHz receiver can sound an alarm when a transmitter moves beyond a predetermined boundary. A similar version of this design idea appeared in the December 12, 2010 issue of EDN . The receiver circuit of Figure ……