Abstract: A Soil Moisture and Electrical Conductivity Probe. The soil moisture probe employs brass ring pairs, wherein each pair incorporates dual feedpoints. There is a single main control circuit for operating the plurality of sensor ring pairs in a multiplexed approach. In order to allow for multiplexed operation, each sensor ring pair includes a signal tuning assembly. The signal tuning assembly includes apparatus for attenuating the signal noise at each sensor ring pair, as well as apparatus for matching the ring-pair to ring-pair lead impedence. The temperature of each ring pair is individually detected to improve the accuracy of all of the sensor ring pairs. This temperature sensing is accomplished by multiplexing a single reference voltage with all of the sensor rings, and by implementing a thermistor at each sensor ring pair.

Abstract: A Soil Moisture and Electrical Conductivity Probe. The soil moisture probe employs brass ring pairs, wherein each pair incorporates dual feedpoints. There is a single main control circuit for operating the plurality of sensor ring pairs in a multiplexed approach. In order to allow for multiplexed operation, each sensor ring pair includes a signal tuning assembly. The signal tuning assembly includes apparatus for attenuating the signal noise at each sensor ring pair, as well as apparatus for matching the ring-pair to ring-pair lead impedence. The temperature of each ring pair is individually detected to improve the accuracy of all of the sensor ring pairs. This temperature sensing is accomplished by multiplexing a single reference voltage with all of the sensor rings, and by implementing a thermistor at each sensor ring pair.

Abstract: A Wireless Subterranean Soil Monitoring System. The system measures the complex permittivity around a subterranean antenna, and then responsively adjusts the antenna's tuning circuit according to the measured permittivity. Once tuned, the system will then execute the transmission of the probe data. Furthermore, the antenna design is adapted for subterranean use to further reduce the de-tuning effect of the adjacent soil.

Abstract: A Wireless Subterranean Soil Monitoring System. The system measures the complex permittivity around a subterranean antenna, and then responsively adjusts the antenna's tuning circuit according to the measured permittivity. Once tuned, the system will then execute the transmission of the probe data. Furthermore, the antenna design is adapted for subterranean use to further reduce the de-tuning effect of the adjacent soil.

Abstract: A duplexer filter assembly, and an associated method, for a communications device capable of operation at a frequency-band set. Separate duplexer filters, each formed of a transmit part and a receive part, are switchingly coupled to the communication circuitry of the communication device. A selected one, or the other, of the duplexer filters is connected to the communication circuitry by switch circuitry depending upon at which parts of the communication device is to be operated.

Abstract: The present invention provides a power supply arrangement with a DC-to-DC converter (10) for providing at least one supply voltage to a load (20, 30, 40) from an energy source (11). The converter comprises means for inputting (4) a battery voltage from the energy source to output a voltage in a predetermined battery voltage range and a transfer circuit (8) connected to said means for inputting, to convert the battery voltage to at least one supply voltage in such a way that the supply voltage will be opposite in polarity to the battery voltage and the absolute value of the supply voltage will be the same or close to the absolute value of the battery voltage. The arrangement also comprises means for controlling (2), connected to the means for inputting, to control the supply voltage independent from the battery voltage using a single converting mode for the supply voltage range.

Abstract: The present invention provides a power supply arrangement with a DC-to-DC converter (10) for providing at least one supply voltage to a load (20, 30, 40) from an energy source (11). The converter comprises means for inputting (4) a battery voltage from the energy source to output a voltage in a predetermined battery voltage range and a transfer circuit (8) connected to said means for inputting, to convert the battery voltage to at least one supply voltage in such a way that the supply voltage will be opposite in polarity to the battery voltage and the absolute value of the supply voltage will be the same or close to the absolute value of the battery voltage. The arrangement also comprises means for controlling (2), connected to the means for inputting, to control the supply voltage independent from the battery voltage using a single converting mode for the supply voltage range.

Abstract: A differential line output cell (10) contains a current source (M1,M2) having an output; a plurality of switches (S1,S2,S3,S4) arranged in a bridge configuration and coupled between the output of the current source and ground, and a capacitance (C) coupled between the output of the current source and ground. In a preferred embodiment the differential line output cell, including the capacitance, are fabricated as part of an integrated circuit, such as an RF IC (20) or a BB IC (30) of a mobile station (50). The capacitance has a value selected to charge a capacitance associated with output lines (5A,5B), which in the preferred embodiment are a pair of PWB traces.

Abstract: A duplexer filter assembly, and an associated method, for a communications device capable of operation at a frequency-band set. Separate duplexer filters, each formed of a transmit part and a receive part, are switchingly coupled to the communication circuitry of the communication device. A selected one, or the other, of the duplexer filters is connected to the communication circuitry by switch circuitry depending upon at which parts of the communication device is to be operated.

Abstract: A communication system includes a mobile station (100) having a transmitter (210) operating on one of a plurality of frequency channels in a first RF frequency band; an associated local area communication subsystem (304) operating by frequency hopping amongst a plurality of channels in a second RF frequency band and a controller (120) that operates in one embodiment for altering a frequency hopping pattern of the local area subsystem as a function of a currently specified frequency channel in the first frequency band. The frequency hopping pattern is preferably also altered as a function of a bandwidth of the currently specified frequency channel of the mobile station. The frequency hopping pattern is altered if the currently specified frequency channel is one having a harmonic frequency that lies in the second frequency band.

Abstract: In a satellite mobile telephone a radio signal is transmitted by firstly generating (602) a digital input signal. The digital input signal is processed (703) in combination with a digital modulating signal (704) to produce a digital intermediate signal. The digital intermediate signal is converted (705) into an analog intermediate signal and said analog intermediate signal is processed (706) in combination with an analog modulating signal to produce a radio frequency output signal. Similarly, during reception, a received signal is processed in combination with an analog demodulating signal to produce an analog intermediate signal. The analog intermediate signal is sampled to produce a digital intermediate signal and said digital intermediate signal is processed in combination with a digital demodulating signal so as to select a transmitted channel.

Abstract: An antenna module suitable for use with a radio telephone is disclosed. The antenna module 200 comprises an antenna 132, suitably multifilar configuration, and a support 118 which supports the antenna. The support also supports a filter 128, 124 which is electrically coupled to the antenna, and an amplifier 124 electrically coupled to the filter. The amplifier is non-fixedly coupled to radio circuitry housed within a radio housing 102. Typically, the antenna module can be non-fixedly coupled to the radio housing.

Abstract: In a satellite mobile telephone a radio signal is transmitted by firstly generating (602) a digital input signal. The digital input signal is processed (703) in combination with a digital modulating signal (704) to produce a digital intermediate signal. The digital intermediate signal is converted (705) into an analog intermediate signal and said analog intermediate signal is processed (706) in combination with an analog modulating signal to produce a radio frequency output signal. Similarly, during reception, a received signal is processed in combination with an analog demodulating signal to produce an analog intermediate signal. The analog intermediate signal is sampled to produce a digital intermediate signal and said digital intermediate signal is processed in combination with a digital demodulating signal so as to select a transmitted channel.

Abstract: An encoded marker is transmitted as a paging signal for mobile satellite telephones. The signal is susceptible to Doppler effects, and the processing procedures are arranged to determine the Doppler characteristics of subsequent signals. The marker takes the form of a first frequency sweep occurring in a first direction followed by a second frequency sweep occurring in the opposite direction. The markers are correlated against sweep signatures to produce amplitude peaks. The mid-point between the peaks and the spacing between the peaks allows timing offsets and frequency shifts to be accurately calculated, thereby facilitating the processing of subsequent data signals.

Abstract: The present invention relates to a procedure for using a radio phone (2) with an external amplifying device (1) for receiving, amplifying and transmitting a radio frequency reception signal to the radio phone, in which radio phone a reception frequency signal is supplied to a front end amplifier (9). When the external amplifying device (1) is connected to the radio phone, the front end amplifier (9) of the radio phone is bypassed or the gain thereof (9) is adjusted to be lower. The control signal (OHJ) is preferably a voltage control signal of direct voltage frequency or low frequency produced in the amplifying device (1), which in the amplifying device is added into the reception signal, and in the radio phone separated from the reception signal into a control :signal of the front end amplifier.

Abstract: The present invention relates to a circuit for use in Time Division Multiple Access radio phone systems having transmission and reception cycles. The circuit includes a keyed switch mode power supply of switch-type. The operation of the switch-mode power supply (2) is keyed to take place outside the reception cycles and transmission cycles of the signal.

Abstract: A radio telephone system and method of operation thereof, wherein the power consumption of the mobile stations in the system is reduced. The system includes a base station, at least one auxiliary base station and at least one mobile station. The levels of the received signals are indicated at the base stations and their levels are compared. The one having the highest indicated level will be selected as the receiving base station. At the same time, the base station transmits the pilot message to the mobile station in order to adjust its transmission power to a suitably low level.