AUTOMATIC REFERENCE OSCILLATOR TUNING STRATEGY
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2001-Nov-12
The Automatic Reference Oscillator Tuning Strategy (AROTS) is designed to adjust the portable's synthesized first oscillator (1st LO) frequency to match the received signal within a predefined channel spacing. This frequency correction capability for receive mode can be used during transmit via sample-and-hold circuitry or can be disabled to allow transmission at the predefined nominal frequency. These features allow for optimization of the transceiver's operation, thereby providing for reduced distortion and improved sensitivity over a wider range of the assigned channel spacing. AROTS based techniques would also be a simple but effective means in compensating for Doppler frequency shifts in transmitted signals from satellites in non-geosynchronous orbits. This may be of some value when implement- ing a satellite-based national coverage communication network. The main advantage would be the ability to use less expensive reference oscillators which can be retuned internally by monitoring a control channel (ie: trunked systems) and adjusting the reference oscillator via p p control. This could result in significant cost savings while not compromis- ing the tolerance required for the reference oscillator. The Automatic Reference Oscillator Tuning Strategy is illustrated in Figure 1.