Abstract: A directional coupler (103) for radio equipment couples a radio frequency signal from an input of a microstrip transmission line (309) to an output and provides a directionally coupled output via a stripline microstrip (311). Open circuit microstrip transmission line stubs (313 and 315) are tuned to a quarter wavelength of the third harmonic of the radio frequency to provide third harmonic rejection within the directional coupler.

Abstract: The present disclosure includes a discussion of a radio receiver. The radio receiver has at least two operational states and includes a variable gain amplifier and at least two adaptive DC offset compensators (421, 427) to suppress undesired DC offset. The first operational state of the radio receiver (121) adjusts the adaptive DC offset compensator circuits (421, 427) to appropriate output levels in absence of an input signal to the radio (121). The second operational state receives the input signal through the radio receiver (121) and eliminates the undesired DC offset (309) from the received input signal with the adaptive DC offset compensator circuits (421, 427) and allows the received input signals to be processed.

Abstract: A TDMA cellular telephone (600) includes in its transmit signal path, microphone (608), vocoder (612), data format circuitry (601), quadrature modulator (602), 90 MHz local oscillator (606), transmitter with mixer (604), transmitter filter (618), and antenna (620). In its receive signal path, the TDMA cellular telephone (600) includes receiver filter (622) coupled to antenna (620), quadrature demodulator (624), and data deformat circuitry (625). The channel frequency of TDMA cellular telephone (600) is loaded into synthesizer (616) by microcomputer (614) and applied to transmitter (604) and demodulator (624). TDMA cellular telephone (600) is controlled by microcomputer (614) which includes a memory with a control and signaling computer program stored therein.

Abstract: A portable radiotelephone with a keypad, alphanumeric character display, and hands free function is disclosed. A movable flip element of the housing covers a keypad and other control buttons when in a closed, on-hook, position and activates the illumination of the keypad, enables the display, and enables the hands free function when in an open, off-hook, position. The duration of keypad illumination and display activation are timed to reduce battery drain and the hands free function may be deactivated with a hookswitch flash.

Abstract: A unique cellular telephone (100) digitally frequency locks to the received base station transmitter signal. The cellular telephone (100) includes a radio transceiver (106), a reference oscillator (104), and microcomputer (102) with memory therein for controlling the operation thereof. The radio transceiver (106) includes a phase-locked loop (PLL) synthesizer 120, a receiver mixer (122) followed by one or more gain stages (124), a phase detector (126), and a divider (128). The PLL synthesizer (120) generates a signal locked to the reference oscillator (104) that is mixed with the incoming base station transmitter signal in the receive mixer (122) to generate an intermediate frequency signal. The output of the reference oscillator (104) also feeds the divider (128), which divides the reference oscillator signal by an amount so as to generate the divided signal having a frequency substantially the same as the frequency of the intermediate frequency signal from the mixer (122).

Abstract: A fractional-N type frequency synthesizer (700) for use in a radiotelephone (901). The synthesizer (700) utilizes multiple latched accumulators (401, 403, 405, 407), within an accumulator network, to perform multiple integrals of an input signal (439). The outputs of the accumulators are combined in series to form a data output signal (453). The data output signal (453) is input to a divider network (703) and used as a variable divisor of the frequency input from a variable oscillator (701) into the divider network (703).

Abstract: A battery type detector for battery-using and battery-charging equipment is disclosed. Operational characteristics of the using and charging equipment are modified in accordance with the battery type detected.

Abstract: A unique process metallizes a substrate surface using a reducing agent including a borohydride to reduce, in a starved reaction, metal oxide particles (300) substantially uniformly distributed and at a controlled concentration in a particle-filled resin (204) to produce catalytic island areas (301). The catalytic island areas (301) formed have a surface resistivity greater than 10.sup.6 ohms per square. These catalytic island areas (301) are then electrolessly metallized to a predetermined thickness, such that adjacent catalytic island areas (301) are interconnected and form metallic features, such as pads, vias (213), and conductors (210, 211 and 212). The starved reaction limits the reduction of metal oxide particles (300) to catalytic island areas (301) and prevents migration of reduced metal beyond each of the exposed surfaces of particle-filled resin (204) which are to be metallized.

Abstract: An amplifier which contains two amplifier stages. Each amplifier stage (433,435) utilizes a diode (407) to attenuate the RF input signal (401) and to stabilize the bias current over temperature. The two amplifier stages (433,435) are cascaded together. The control voltage inputs are serially coupled through a transistor (423). The transistor (423) shifts the voltage of the control signal (425) down, thereby, shifting the control characteristics and AM characteristics of the first amplifier stage (435) relative to the second amplifier stage (433).

Abstract: A communications receiver (103) comprising a carrier recovery apparatus having an adjustable response time loop filter (123) responsive to carrier signal parameters determined by a signal processor (141) is disclosed. Signal reception under fading conditions is improved by detecting the received signal parameters in an energy level determinator (207), a rate of change of energy level determinator (209) and a look-up table value (221) corresponding to a position of TDMA time clock (219).

Abstract: A multiplexed synchronous/asynchronous data bus is disclosed in which three bus lines are used to convey bidirectional synchronous data between at least two data devices at a relatively low data rate. Valid half duplex asynchronous data is applied at a higher data transfer rate to one of the three bus lines when only one of the bus lines is held in a logic high state.

Abstract: A channel bank speech synthesizer for reconstructing speech from externally-generated acoustic feature information without using externally-generated voicing or pitch information is disclosed. An N-channel pitch-excited channel bank synthesizer (340) is provided having a first low-frequency group of channel gain values (1 to M) and a second high-frequency group of channel gain values (+1 to N). The first group controls a first group of amplitude modulators (950) excited by a periodic pitch pulse source (920), and the second group controls amplitude modulators excited by a noise source (930). Both groups of modulated excitation signals are applied to the bandpass filters (960) to reconstruct the speech channels, and then combined at the summation network (970) to form a reconstructed synthesized speech signal. Additionally, the pitch pulse source (920) varies the pitch pulse period such that the pitch pulse rate decreases over the length of the word.

Abstract: A leaded electrical component 101 for surface mount applications having a receptacle 107 attached to the component 101 which renders the resultant assembly 127 capable of mounting to the top surface of the substrate 129. The top of the receptacle 111 provides an opaque, smooth surface enabling the assembly to be picked up and placed using automatic equipment with a vision system. The bottom of the receptacle 113 rests on the top surface of the substrate 129 to provide stability for the surface mount assembly 127. The receptacle 107 captures the component 101 in a secure position. The captured component 101 provides a specific orientation until the leads 109 are coupled to the substrate.

Abstract: A method and apparatus for remotely loading a telephone number into a mobile unit is disclosed. A registration computer in a credit card payment radiotelephone system places a call to a mobile radiotelephone unit and conveys a telephone number to the mobile unit which is stored at the mobile unit. This telephone number may later be recalled and transmitted by the mobile unit to accomplish a telephone call.

Abstract: A cellular cordless telephone (10) operates with both a cordless base station (180) and a cellular base station (190) and cellular control terminal (196). In one embodiment (FIG. 2) , a cellular cordless telephone (100) includes a cellular transceiver (120), antenna (128), keyboard (140), a display (180), handset (160), and microcomputer (130) together with a cordless transceiver (110) and antenna (118), all of which may be in a single housing. In another embodiment (FIG. 3), a cellular cordless telephone (200) includes a cellular telephone (220) and a cordless telephone transceiver (210) which may be a plugable module. Whenever cellular cordless telephone (10) is within range of cordless base station (180), telephone calls may be made over the cordless radio channel or transferred from the cellular radio channels to the cordless radio channel.

Abstract: Electromagnetic shielding apparatus for portable telephones (300) and other electronic equipment, includes shield clips (100) for intercoupling the conductive surfaces of a housing (302 and 303) to the metal layer (205) of the circuit board (200). Each shield clip (100) mates with a corresponding edge (204) of the circuit board (200) such that tabs (208, 209, 210) insert into holes (108, 109, 110) in the central channel (111-113) of the clip (100) and feet (101, 102, 103) of the clip rest on other tabs (201, 202, 203). The clip (100) is bonded to the metal layer (205) of the circuit board preferably by resistance welding, thereby reliably connecting the clip (100) and the conductive housing surfaces to signal ground.

Abstract: A unique cellular telephone (100) connects to a standard telephone set (101) for providing cellular telephone services to subscribers in remote locations not served by a landline telephone system. Cellular telephone (100) includes a cellular telephone transceiver (109), microcomputer (108) and circuitry (102-106) for interfacing the cellular telephone transceiver (109) to the telephone set (101). The interface circuit (102-107) provides the audio, voltage and dial signal interface to the telephone set (101). The microcomputer (108) controls the interface circuitry (102-106) and is responsive to the telephone set (101) for answering and placing cellular telephone calls.

Abstract: A fractional-N synthesizer realizes automatic frequency control by adding (509) a digital representation of a determined frequency offset to a digital representation of applied modulation to create the modulus control of a programmable frequency divider (203).