Abstract: A system and method to load and unload railcars using stackable trays having an internal propulsion system.

Abstract: A carrier-recovery loop for a receiver in a communication system with features that facilitate initialization of the loop. The carrier-recovery loop is a PLL that uses a feedback signal to keep a recovery oscillator phase-locked to the carrier of a received signal. In the present invention, an initializing value of the feedback signal is stored in a memory and provided to a digitally controlled recovery oscillator (DCO). This initializing value brings the recovered signal to an initial frequency that approximates the carrier frequency. When the receivers starts to acquire a phase-lock with the carrier, the carrier-recovery loop is in a condition close to the desired phase lock. Preparing the DCO in this manner imparts a significant improvement to the carrier-recovery loop. The response time for the loop to acquire a phase lock depends in part on its initial frequency offset from the carrier. In general, reducing this initial offset reduces the loop's acquisition time.