Abstract: In a trunked communication system that supports roaming communication units, communication capabilities in support of the communication activities of the communication unit may be varied from system to system in a controlled manner. This control may be initiated at the instance of the communication unit itself, on a system by system basis (wherein each system maintains a data base and/or retains the capability of contacting a home system for the communication unit), or by a hub that interconnects with each of the trunking systems and which either maintains a data base of preauthorization information or that contacts home systems in order to obtain authorization information.

Abstract: An improved multifrequency trunked, two-way communications system is provided in which a plurality of conventional single channel radio units are provided access. The system includes a predetermined number of information channels that are shared by a plurality of trunked stations. A trunked controller assigns one of the information channels to a requesting trunked mobile unit. The requesting trunked mobile unit is enabled to operate on the assigned channel in response thereto.The improved communications system includes a radio access link which enables the single channel radio units to operate on an assigned information channel in the same manner as the trunked remote stations. The radio access link provides the plurality of conventional remote stations automatic access to the trunked system without requiring any modification of the conventional remote stations, and likewise without modification of the trunked remote stations and trunked controller.

Abstract: A digital voice privacy electronic communication system and method provides protection for an information signal. Either a clear voice signal or a scrambled digitized version of the voice signal is selected for transmission. At the receive end of the system a determination that a clear voice signal or a scrambled signal has been sent is made. This information is used to automatically switch the clear audio signal if present to an output circuit or to switch to the output circuit either a regenerated version of the scrambled signal or an unscrambled version of the information signal. The switching is done automatically so that a user does not have to manually select the proper receiver mode in response to reception of a signal, that is, whether the received signal was a clear voice signal or a scrambled signal. At the transmitter the information signal to be scrambled is analog-to-digital converted and the digital signal is then put into a scrambled form.

Abstract: An apparatus for rapidly conditioning wax samples and a method for determining the oil content of said samples with a nuclear magnetic resonance analyzer are described. A molten wax sample is collected in a sample holder. The holder is then placed in a temperature equilibration chamber where the molten wax is rapidly cooled at a temperature of about 25-33.degree.F with a cold gas stream from a vortex tube. The sample is then heated to a pre-selected equilibration temperature for a preset time at which point the sample is removed from the equilibration chamber. The sample is placed in the analyzer where the nuclear magnetic resonance value of the sample is determined. The sample is removed from the analyzer and weighed. Finally the oil content of the wax sample is obtained from a previously developed correlation between the oil content and the nuclear magnetic resonance value of various wax samples.

Abstract: An apparatus for rapidly conditioning wax samples and a method for determining the oil content of said samples with a nuclear magnetic resonance analyzer are described. A molten wax sample is collected in a sample holder. The holder is then placed in a temperature equilibration chamber where the molten wax is rapidly cooled at a temperature of about 25.degree.-33.degree.F with a cold gas stream from a vortex tube. The sample is then heated to a pre-selected equilibration temperature for a preset time at which point the sample is removed from the equilibration chamber. The sample is placed in the analyzer where the nuclear magnetic resonance value of the sample is determined. The sample is removed from the analyzer and weighed. Finally the oil content of the wax sample is obtained from a previously developed correlation between the oil content and the nuclear magnetic resonance value of various wax samples.