Abstract: Methods and apparatus for dynamically calibrating a modulator in a radio transmitter are provided. In a preferred embodiment an In-Phase and Quadrature (I/Q) modulator in a radio modem is calibrated by means of a modulator, a digital signal processor and a power sensor. The modulator being electrically adapted to receive a local oscillator input having a carrier frequency and a substantially direct current (DC) input having an amplitude in order to produce an output having a power magnitude at the carrier frequency in a frequency defined power spectrum. The power sensor being in electrically succession to the modulator to measure the power magnitude of the output to permit the digital signal processor (DSP), electrically between the modulator and the power sensor, to compare the measured power magnitude with a minimum threshold power magnitude to determine which is greater.

Abstract: In cellular telephone handset having an upper casing and a lower casing, liquid crystal display screens with touch sensitive overlays are provided on each casing. In one mode of operation, the screen on the lower casing will display a telephone keypad and the telephone handset will respond to the touching of the keys from the telephone keypad to dial telephone numbers and will display information on the screen on the upper casing. In a second mode of operation, the screen on the upper casing will display function keys and the telephone handset will respond to the touching of the function keys and will display information on the screen on the lower casing.

Abstract: A subscriber unit (100) of a messaging system initiates (226) a reminder alarm action. The user generates (210) an intended message to be sent as an inbound message with a user interface (114). The processing system (106) of the subscriber unit (100) evaluates (214) a characteristic of the intended message, and initiates (226) the reminder alarm action in response to the evaluating (214) step. The processing system (106) and the coupled transmitter transmit (228, 242) the inbound message.

Abstract: An amplifier system (100) for transmitting wideband multicarrier communication signals in a satellite communication system uses wideband envelope elimination and restoration amplifiers (200). The system upconverts channelized IF signals to provide a wideband multicarrier RF output signal between 20 and 30 GHz having a bandwidth between 100 and 200 MHz.

Abstract: A wireless base station has a transmitter and receiver. Transmission signals are applied to an antenna through a transmit bandpass filter that is tuned for a transmit band of frequencies. Received signals from the antenna are applied to the receiver through a receive bandpass filter that is tuned for a receive band of frequencies. An RF switching array consisting of four RF switches interconnects the output of the transmitter and the input of the receiver such that normal, loopback (self-test), and scanning modes can be performed. In the normal mode, the antenna is connected to the transmitter and receiver through the transmit and receive bandpass filters, respectively. The transmit and signal paths are effectively isolated from each other by three serially-connected open switches. In the loopback mode, the transmitter output is connected to the receiver input. In the scanning mode, the antenna is connected to the receiver through the transmit bandpass filter.

Abstract: A converter for a satellite signal receiving antenna, comprising a input terminal for inputting a signal in a frequency band other than the output frequency band of the IF signal converted from the satellite signal, and where the IF signal and signal from the input terminal are mixed by a mixing circuit, and output through a coaxial cable from the IF output terminal.

Abstract: From layout and attenuation data of an area and an initial guess, the placement and power levels of base stations and the resulting attenuation and base station ranges are calculated based on any chosen propagation model. A cost function is calculated which indicates the merit of the initial guess placement. The cost function is a function of the transmitter locations and power levels and can be calculated as a linear combination of the uncovered and interference areas. Other cost functions can also be considered. The cost function is optimized by one of several optimization methods to give the optimal base station placement. The optimization can be continuous or discrete. Continuous optimization methods include the modified steepest descent method and the downhill simplex method, while discrete optimization methods include the Hopfield neural network method. The optimization can be performed several times for different initial guess placements to achieve a global, rather than simply local, optimization.

Abstract: The battery life of a portable radiotelephone is increased by providing a variable instead of a fixed value of collector-emitter current for the low noise transistor in the RF receiving stage. In particular, the collector current of the RF receiving stage is microprocessor controlled in inverse proportion to the strength of the received signal, an indication of which is advantageously taken from the normally provided "RSSI" output signal provided by the radiotelephone set's conventional IF chip. The microprocessor stores an indication of the correct amount of base current drive to be supplied to the RF transistor to determine its collector current for strong signal and weak signal conditions as well as monitoring collector current for varying base drive to compensate for temperature effects.

Abstract: Control circuitry and an associated method for a modified-user, wireless communications system, such as a cellular communication system wherein groups of mobile transceiver units are positioned to travel together. Circuitry is positioned to travel together with the group of mobile transceiver units and to generate common control requests to control operation of the entire group of mobile transceiver units. When embodied in a cellular communication system, a common hand-off request is generated for the entire group of mobile transceiver units, obviating the need for each transceiver unit to independently generate a hand-off request. If a mobile transceiver is operable pursuant to an air interface standard dissimilar to a fixed-site transceiver with which communications are to be effectuated, a converter converts communication signals so that the communication signals can be communicated therebetween.

Abstract: A method and circuitry for improved output power level calibration/compensation/control is disclosed. A single RF detector diode is employed, to which a bias current is applied prior to applying a coupled amount of the transmitted radio frequency signal to be measured during a level calibration or automatic level control function. The initial (pre-RF) voltage out of the detector circuit is stored and later subtracted from the detector's output voltage after application of the RF signal. This results in a voltage proportional only to the detected RF signal, independent of any circuit-dependent voltages and variations due to environmental conditions such as temperature fluctuation, and allowing precise control of the output power levels.

Abstract: In a mobile telecommunication system, a test terminal is disposed in each of radio service zones of a plurality of radio base stations connected to a mobile switching station, and a testing device is connected to the mobile switching station and calling the test terminal to send out a first test pattern through a down link. The test terminal receives the first test pattern and compares the received first test pattern with a second test pattern equal to the first test pattern to send back the compared result as test data through an up link. The test terminal sends out the second test pattern to the testing device through an up link. The testing device defines the radio channel condition of the down link from the test data and the up link from comparison of the first test pattern with the received second test pattern, and sends out an instruction to the test terminal. The test terminal announces comments and displays images for indicating the radio channel condition in the radio service zone.

Abstract: A fixed portion (102) of a radio messaging system schedules (602) an inbound message to be transmitted at a first scheduled time on a channel from a portable subscriber unit (122). The channel is monitored (604) at the first scheduled time to receive the inbound message, utilizing a beamforming technique. In response to failing to achieve adequate reception of the inbound message at the first scheduled time, the fixed portion reschedules (608) the inbound message to be transmitted at a second scheduled time, and remonitors (610) the channel at the second scheduled time to receive the inbound message, utilizing an omnidirectional technique.

Abstract: An apparatus and method produce a plurality of output signals (917-921) with fixed phase relationships therebetween. The apparatus (900) includes a first signal generator (901), a second signal generator (903), and a signal processor (907). The first signal generator produces a first input signal (911) at a first frequency. The second signal generator produces a second input signal (915) at a second frequency, wherein the second frequency is an integer multiple of the first frequency. The signal processor receives the first and second input signals and produces a plurality of output signals (917-921) having fixed phase relationships therebetween at the first frequency, wherein the fixed phase relationships are based on the integer multiple and wherein each of the output signals has a single, determinate phase relative to the phase of the first input signal.

Abstract: A multiplier (10) includes a transconductor (14) and a multiplier core (34). The transconductor (14) converts an RF voltage signal to an RF current signal. The RF current signal modulates the quiescent currents flowing in current conducting elements (23, 24), thereby generating a modulated current signal. The modulated current signal is transmitted to the multiplier core (34), where it is combined with an LO signal to generate an output signal. The transconductor (14) and the multiplier core (34) have their current conduction paths separated from each other by the current conducting elements (23, 24).