Abstract: The cellular telephone interface system has the capability to automatically choose between AMPS and CDMA cellular transmission protocols for data transmissions. The cellular telephone interface system includes a PC-modem card, such as a PCMCIA card, for interconnecting the cellular telephone to a data source, such as a laptop computer, portable facsimile machine, or the like. The cellular telephone is capable of transmission in accordance with either AMPS or CDMA transmission protocols. For AMPS, the PC-modem card converts data signals received from the data source into PCM signals for forwarding to the cellular telephone. The cellular telephone converts the PCM signals into AMPS formatted signals for transmission to a local cellular base station. For CDMA transmission, the PC-modem card converts the data signals received from the data source into RS-232E signals for transmission to the cellular telephone.

Abstract: A cellular telephone that provides the capability of performing Internet telephone calls without the bulk and expense of Internet telephone computer systems. The cellular telephone uses hardware vocoders and communication circuitry already present in the cellular telephone for normal cellular calls to provide the additional Internet telephone functionality.

Abstract: The wireless system includes one or more payphones from which users may initiate payphone calls. A mobile switching center connects telephone calls initiated from wireless payphones to external telephone systems such as the public switch telephone network (PSTN). To meter charges incurred during the telephone call within an external system, the external system transmits periodic metering pulses to the mobile switching center. Each pulse is representative of a predetermined amount of money associated with the telephone call. The rate at which the periodic pulses are transmitted to the mobile switching center depends upon the current billing rate and may be affected by, for example, the time of day.

Abstract: An active phase splitter comprises two or more phase shift circuits. Each phase shift circuit comprises a number of active devices and capacitors. For a single-pole active phase splitter, within each phase shift circuit, two active devices are configured as a cascode amplifier. The first active device is configured as a common source amplifier and the second active device is configured as a common gate amplifier. A capacitor is connected across the gate and drain of the first active device to generates the necessary pole-zero pair for the phase shift circuit. The cascode configuration results in the desired transfer function and provides transconversion of voltage input to current outputs. Active phase splitters with two or more poles can be built using the same inventive concept.

Abstract: A method and apparatus for performing an inter-system soft handoff is described. In accordance with the present invention, when a subscriber unit crosses from a first cellular system to a second cellular system, a base station controller determines if sufficient network resources are available to conduct a inter-system soft handoff. If so, the base station controller generates a set of signaling messages that cause call processing resource to be allocated and for the call to be processed at the second cellular system. The base station controller then perform data-selection and data-broadcast for the call by transmitting data to the subscriber unit by way of the second cellular system as well as via one or more base stations to which the base station controller is directly coupled.

Abstract: A novel and improved method and system for reducing the bandwidth requirements of satellite or wireless communication networks is described. In accordance with one embodiment of the invention, a training sequence is transmitted over a training channel from a terminal to a master station. The master station measures a frequency error of the training sequence, and provides the frequency error to the terminal. The terminal adjusts its transmit frequency by the frequency error, offsetting all further data channel transmissions by the frequency error.

Abstract: The cellular telephone includes a universal asynchronous receive and transmit (UART) chip for receiving data in a serial format from an external source, such as a laptop computer, and for converting the serial data to parallel bytes of data for transmission to a microcontroller of the cellular telephone. The UART operates in one of two modes: a sample mode and a byte mode. In the sample mode, voltage levels of serial data signals received by the UART are detected and sample bytes are generated representative of those voltage levels. The sample bytes are stored within a receive First In First Out (FIFO) queue of the UART for eventual transference to the microcontroller. The microcontroller converts the sample bytes to signals appropriate for transmission using a cellular transmission format such as code division multiple access (CDMA). In the byte mode, the UART receives data bytes as bytes and stores those bytes directly within the receive FIFO without any sampling.

Abstract: An receiver receives, amplifies, filters, and downconverts an RF signal to obtain an FM signal. The FM signal is then limited by a limiter and sampled by an ADC. The FM samples from the ADC are provided to an edge detector which detects transitions in the FM samples. The transitions correspond to zero crossings in the FM signal. The time period between the zero crossings, or the cycle width, is measured with a counter to determine the instantaneous frequency f.sub.c of the FM signal. The demodulated output is proportional to the instantaneous frequency which can be determined from the measured cycle periods as f.sub.c =1/2T.sub.c, f.sub.c .apprxeq.-.alpha.T.sub.c, or f.sub.c .varies.T.sub.c, where T.sub.c is the measured cycle period, and .alpha. is a constant based on the slope of 1/2T.sub.c,avg, where T.sub.c,avg is the average cycle period. The sample rate of the demodulated output can be reduced, through resampling, to minimize power consumption in the subsequent signal processing blocks.

Abstract: A novel and improved method and apparatus for signal acquisition in a wireless telecommunication system having large transmission delay uncertainty is described. A terminal first acquires the forward link signal from a hub and extracts timing information from that forward link signal. Using the timing information the terminal estimates the time at which a next search window takes place during an access slot, and the time and pseudorandom code state necessary to transmit an access probe so as to arrive at during the search window assuming the terminal is located a maximum distance from the hub. The terminal proceeds to transmit additional access probes at times occurring one access slot period plus a delta time interval after the previous transmission. The delta time interval has a duration less than that of a search window associated with each access slot.

Abstract: A ROM circuit that can be modified via the alteration of any one of a set of substance layers is described. The ROM circuit includes a set of ROM cells each of which provide one bit of data used to construct the fixed binary number. Each ROM cell includes a set of circuits that can be placed in either a first or second state via modification of a single substance layer that is different for each circuit, and generates a signal in a logic state that depends on whether the number of circuits in the first state is odd or even. When a design revision occurs the state of one of the circuits from the set of circuits is modified to update the fixed binary number using one of the substance layer already being modified during the course of the design revision.

Abstract: A multi-stage low power, high dynamic range variable gain amplifier comprises an input stage cascaded with one or more current amplifier stages, whereby the gain of each stage may be independently controlled. The input stage may be comprised of a variable transconductance amplifier using variable emitter degeneration. The current amplifier may be comprised of a differential Darlington amplifier coupled to a differential cascode amplifier. The transconductance amplifier converts an input voltage signal to a current signal. The variable gain amplifier is designed for efficient low power operation.

Abstract: A method and apparatus for operating a wireless telecommunication system utilizing code division multiple access (CDMA) over-the-air with a Global System for Mobile communications (GSM) A-interface based network is described. A CDMA radio frequency (RF) signal interface provides a bi-directional interface to a subscriber unit, and a Global System for Mobile (GSM) communications A-interface SS7 transport provides a bi-directional interface with GSM mobile services switching center (MSC). Additionally, a transparent message transport is provided over which signaling messages defined in the GSM A-interface protocol are exchanged between the GSM MSC and a subscriber unit. Other signaling message generating by the GSM MSC and subscriber unit are processed and various actions are taken in response, including the configuration and control of signal processing resources.

Abstract: A circuit card assembly is provided for use in testing a system wherein the circuit card assembly employs a surface mount device such as a field programmable gate array. The circuit card assembly includes severable traces on a bottom surface of the assembly connecting pairs of near and far vias. The severable traces and the pairs of near and far vias allow the circuit card assembly to be selectively re-worked to accommodate changes to the design of the surface mount device. Hence, a new circuit card assembly need not be designed and fabricated each time the design or programming of the surface mount device is changed. The circuit card assembly includes a network of interconnection paths wherein each path to or from a pin terminal area of the circuit card assembly passes along at least one severable trace between at least one pair of near and far vias along the bottom surface of the assembly.

Abstract: An amplifier circuit for providing an amplified signal in response to an input signal. The amplifier circuit includes an input network for applying the input signal to a selected at least one of a plurality of amplifier stages. An output network is provided for coupling the amplified signal from the selected at least one amplifier stage. The appropriate amplifier stage is selected by a control circuit in response to a desired power value of the amplified signal. By selectively activating only the amplifier stage(s) that are necessary to provide the desired level of output power, increased DC efficiency can be accomplished in applications that require an amplifier which operates linearly over a wide dynamic range.

Abstract: The finite impulse response (FIR) filter is implemented as a table using read-only memory (ROM). The FIR filter table stores a pre-calculated output filter value for each permissible combination of input values to be filtered. Streams of input values are successively shifted into the table and corresponding output values are successively output. In an exemplary implementation, the FIR filter is employed within a digital cellular telephone for use in smoothing a digital signal to be transmitted. The size of the required FIR filter table is minimized by exploiting constraints imposed upon the signal to be filtered and by exploiting linearity and symmetry within the filter itself. More specifically, the telephone employs a data burst randomizer to provide a data signal composed of sequences of null or 0 values and sequences of antipodal values (+1's and -1's).

Abstract: A plurality of methods for achieving the softer handoff process such that the performance of a system is improved. A first method is based on delaying the softer handoff process. A second method is based on reducing the power of transmissions from the sector having the weakest signal strength. A third method is based on eliminating transmissions from the sector having the weakest signal strength. In all three methods, reverse link demodulation in each sector may continue with or without the transmission of the forward link. In all three methods the operation could be based on the signal strength of the reverse link signal or the forward link. It is also possible to combine two or more of these methods to create a hybrid method.

Abstract: A novel and improved method and apparatus for providing an interface to a digital wireless telephone system compatible with standard analog wire line telephones, analog wire line fax machines, and computer modems is described. At the start of a telephone call, a data pump interprets the digits dialed, and if a first set of digits are received a control system configures the data pump for processing analog fax data. If a second set of digits are received, the control system configures the data pump for processing analog computer modem data. If a telephone number is received, the control system configures the interface system to pass additional data to a vocoder which encodes any digitized audio information received.

Abstract: The present invention is a novel and improved method and apparatus for implementing a latch within an integrated circuit. Data is stored on a storage node via the application of either a first or second state logic source applied through a feedback inverter that maintains the storage node at a particular logic state. During logic transitions from a first state to a second state the storage node is decoupled from the first state logic source via the use of a gating circuit, and the new logic level is applied to the storage node. During logic transitions from the second state to the first state the storage node remains coupled to the second state logic source. The coupling and decoupling of the storage node from the first state logic source is performed via the use of a clock signal that has a non-overlapping cycle with respect to a second clock signal that is used to control the transitions of the state of the latch.

Abstract: A method and apparatus for constructing high rate trellis codes for PSK modulation that can be encoded and decoded using the encoder and decoder for a rate 1/2 punctured convolutional code. In particular, the design of trellis encoders and decoders for 2.sup.k -PSK modulation for rates (km-1)/km for k.gtoreq.3 and m.gtoreq.1 is provided.