Abstract: A receiver for a carrier that is swept in frequency in a predetermined manner over a bandwidth comprises frequency tracking with continuous self-synchronization. The frequency tracking permits the carrier to be filtered by a narrowband filter. The filtered carrier is then fed to a frequency discriminator to produce an error signal. A highly-selective phase-locked loop synchronizes only to the desired component of the error signal in frequency and in phase. The output of the phase-locked loop, after appropriate shaping, is the control signal for tracking synchronously the incoming wave. The output data are obtained at detection after the narrowband filtering.

Abstract: An industrial process control system to be used with processes which are geographically spread out over a relatively wide field area, with portions thereof located in respective zones, and wherein the process has associated therewith a large number of instrumentation elements including sensing elements and operating elements for controlling actuators such as process valves. The control system includes a central station with a digital computer which directs signals to a number of primary transmitter/receiver units each producing a swept-carrier wireless signal for transmission to a respective one of the field area zones. Within each zone are a plurality of local transmitter/receiver units similar to the primary units, with each local unit being assigned to one or more sensing elements and/or one or more operating elements.