Abstract: The present invention provides an apparatus (200) and method (500) for providing a baseband digital error signal in an adaptive predistorter. A carrier cancellation circuit (202) provides a difference (212) between a first signal (208) based on an amplifier output and second signal (210) based on a data input. A quadrature demodulator (204) provides a baseband analog error signal (214) based on the difference (212). An analog-to-digital converter (206) provides the baseband digital error signal (216) based on the baseband analog error signal (214).

Abstract: An improved network interface architecture for a packet switch provides a mechanism for handling voice and data packets. Bandwidth allocation can be changed because control and data memories are synchronized to one another. A hierarchical addressing technique is employed to enhance flexibility in handling packet information. This method permits packet message data and certain packet control data to be stored in memory locations without having to be duplicated at a different memory location prior to transmission of the packet. In an exemplary wireless TDMA packet network a control module (CM) sends a time stamp relative to the beginning of its frame in a synchronization packet allowing each of a plurality of user modules (UM) to maintain synchronization relative to the CM. The CM uses a plurality of directional antennas and transmits the synchronization packets over each antenna over a predetermined number of frames.

Abstract: A feedforward distortion minimization circuit includes a first loop with an input splitter and first and second signal paths, each signal path having an amplifier. An output combiner couples the two signal paths and has an output signal path and an output dump load path. A first signal detector on the dump load path detects a dump load signal, and in response a gain and phase controller operates to adjust the gain and phase of a first signal on one of two signal paths to minimize the power delivered to the dump load. The feedforward circuit also includes embodiments in which both amplifiers operate at around the same power amplification level, and in which a second loop has an error amplifier for further distortion correction.

Abstract: A method and apparatus for combining multipath spread-spectrum signals are provided. The multipath combining is accomplished by detecting an envelope of an input differential phase shift keyed signal communicated over a communication channel. Subsequently, a replica of a multipath echo structure for the communication channel is detected within the detected envelope. In addition, a multipath echo structure weighted differential phase shift keyed signal with the detected replica of the multipath echo structure for the communication channel. Finally, the multipath echo structure weighted differential phase shift keyed signal is integrated over a one symbol period centered on a correlation peak such that power from a plurality of signal paths determines an output data bit.

Abstract: A method and apparatus is provided for controlling peak envelope power level in a power amplifier (PA) (10). The method includes the steps of measuring (101) a first peak envelope power value of an input of the PA during a first time period, comparing (102) the first peak envelope power value with a threshold value, and introducing a phase change (103) into a selected signal of a plurality of signals being amplified by the PA when the first peak envelope power value exceeds the threshold. The method further includes measuring (104) a second peak envelope power value during a second time period, comparing (105) the first and second peak envelope power values, and reversing (106) the phase change to the selected signal when the second peak envelope power value exceeds the first peak envelope power value.

Abstract: Power control circuitry (100) uses two attenuators in the transmit path to achieve wide dynamic range. An intermediate frequency (IF) attenuator (200) is placed before a mixer (212) in the IF section of the transmit path and a radio frequency (RF) attenuator (221) is placed after the mixer (212) in the RF section of the transmit path. Power control circuitry (236) controls setting of the two attenuators in response to a magnitude control signal (102) related to a RF output signal at a desired power level. To conserve battery power of the subscriber unit, only the RF attenuator (221) is adjusted when the desired power level is to be within a given range below the maximum transmission level. For ranges below the given range, the RF attenuator (221) is set for maximum attenuation and the IF attenuator (200) is adjusted.

Abstract: A non-hermetic, three-dimensional, microwave semiconductor device carrier with integral waveguide couplers is disclosed. A molded plastic substrate having a suitable dielectric constant and varying thicknesses comprises plated conductors and locations for receiving GaAs MMIC's. MMIC's are mounted to a metal backplate and die bonded to the plated conductors. The waveguide couplers are integrally molded as part of the carrier substrate, and comprise plated through cylindrical members. Signals from a waveguide cavity are coupled to the MMIC's by inserting the waveguide couplers into a waveguide port. The carrier and integral waveguide coupler together with a plated molded cover forms a non-hermetic package providing pseudo-shielding cavities about the resident multiple semiconductor GaAs die. Transmission line impedance control is enhanced varying the substrate thickness on a per conductor basis. Frequency of operation exceeds 12 gigahertz.

Abstract: An interference detecting circuit is used in a cellular radiotelephone communication system which employs angular modulated frequencies in order to determine when to change the communication process so as to maintain the integrity of the communication path. For example, when the circuit detects an excessive amount of multipath or co-channel interference on a channel serving an active call, the system may decrease the effective data bit rate. The circuit includes a logarithmic envelope detector for receiving a channel's angular modulated signal and for providing a log envelope output signal, a high pass filter for removing a particular range of undesired frequencies from the log envelope output signal, and a level detector for indicating the level of filtered output signal. The output of the level detector represents the amount of interference on the angular modulated frequency signal. A microcomputer analyzes the amount of interference to determine when such communication process changes are desired.

Abstract: A telephone set incorporates a conventional keypad to allow the user to program a custom ring tone and pattern into the telephone set. After such programming is established, when the telephone set detects a ring signal from the central switching station, a ringer is activated and deactivated according to the programmed ringing parameters so as to provide a truly customized ring signal to the user.

Abstract: A leadless chip carrier for RF power transistors or the like is disclosed which includes a body of insulating material having two major surfaces and side walls joining the major surfaces. In a first embodiment, a pattern of conductive pads is deposited on one major surface. A pattern of conductive contact areas is deposited on the other major surface and distributed interconnecting portions of conductive material are deposited to connect the pads to the respective contact areas. In a second embodiment, larger pads and contact areas are provided on a beryllia substrate to provide a leadless chip carrier for RF transistors capable of handling 8 watts. In a third embodiment, a single slot is made conductive to provide the distributed interconnecting portion for one terminal, while in a fourth embodiment, the slot is changed to a plurality of small, tungsten-filled through holes to provide a virtually hermetically sealed leadless chip carrier for RF power transistors.

Abstract: A high efficiency RF power amplifier is disclosed in which a field effect transistor is operated in a class F mode. A third harmonic quarterwave open circuit transmission line stub having a Z.sub.O adjusted to provide capacitance series resonant with transistor inductance at the second harmonic is coupled to the transistor output lead to produce a low impedance at the channel drain of the transistor. Parallel resonance of the transistor die capacitance and interconnect inductance coupled to ground by the transmission line produces a third harmonic high impedance at the channel drain. Further lowpass output matching circuitry provides a constantly increasing impedance magnitude from the transistor die to the load and provides load mismatch isolation to the second and third harmonic impedances at the channel drain.

Abstract: Unique multi-level power amplifying circuitry is described that may be advantageously utilized in duplex portable radio transceivers which may be inserted into a vehicular adaptor for operation from the vehicle battery. Upon detecting the presence of the vehicular adaptor, the power amplifier may be operated at a second set of power levels which include levels greater than a first set of power levels for portable operation. The multi-level power amplifying circuitry of the present invention may be advantageously utilized in a variety of applications where duplex battery-operated radio transceivers may be inserted into a vehicular adaptor for operation from the vehicle battery.

Abstract: A transmitter power control circuit which provides normal power control functions, and provides a high speed loop response when abrupt changes in output power are required. The circuit utilizes an electronic switch to provide adaptive filtering to permit narrow bandwidth filtering during normal steady state operation of the transmitter and wide bandwidth filtering during desired abrupt changes in transmitter power output. This allows rapid changes in transmitter output power when desired, while substantially eliminating undesired noise during normal operation.