Abstract: A system for tracking and correcting drift and dispersion of carrier frequencies in a transmitted signal which includes one or more carrier frequencies and a pilot frequency. The system includes one or more carrier tuners, each for receiving the transmitted signal and for deriving from the received signal and IF carrier signal representing a respective carrier frequency, a mixer for mixing the IF carrier signal and a local oscillator signal to produce a resultant IF information signal, and a demodulator for demodulating the resultant IF information signal to recover the transmitted information.

Abstract: A satellite locating system for use in a satellite communication system having a transmitting station in which radio signals with signal identification data is transmitted via a satellite to a receiving station.

Abstract: A portable data recorder for recording time-related information on tape cassettes. The recorder includes a briefcase shell in which the other components are mounted, a keyboard having a plurality of keys each of which, when depressed, produces a signal, and a plurality of key lines each coupled to a different one of the keys for carrying the signals produced thereby. A multiplexer, under control of a microprocessor, sequentially samples the key lines and transfers to the microprocessor any signals present on the key lines. The microprocessor then records on a cassette recorder data indicating whether or not a signal was present on each of the key lines sampled, and the time of sampling the key lines. The multiplexer successively samples the plurality of key lines so that both the identity of the keys depressed and the time duration of depression of the keys are recorded.