Toward wireless receivers without crystals

In new low cost, low bit rate wireless protocols such as Zigbee™ and Bluetooth™, there is significant economic motivation to implement transceivers with a completely integrated alternative to quartz crystals. In this paper, we explore a differential detection based method of recovering a direct sequence spread spectrum signal with a receiver that does not have a crystal reference. Despite the additional frequency offset and phase introduced by using an integrated crystalless reference oscillator, we find that such a receiver is feasible and can perform sufficiently for many applications.