Abstract: A method and receiver for demodulating a DS/CDMA signal increases a receiver's (60) sensitivity and as a result the system capacity of a DS/CDMA cellular communications system. A Reduced State Sequence Estimator (RSSE) (68) finds a path (210) with the highest energy. An efficient method and apparatus for determining the path energies (212) selects a new path (210) to differ from a previous path (210) by a single reduced state (200). A difference (306) between an I and Q magnitude of the new and omitted reduced state (200) is computed (304). This difference is added to the previous path's total I (308) and Q magnitude, to compute the new path's I and Q magnitude. These I and Q magnitudes are used to compute a path energy (322) and the highest path's energy (326) is used to select the best path for decoding (70).

Abstract: A radiotelephone (300) having timer shutoff feature and a roam shutoff feature. The timer shut off feature implements a process (102-114) in which a processor (310) determines (106) if a flip (408) is closed or an end key (410) has been pressed. If either of these events occur a timer is started (108). If the timer exceeds (110) a predetermined period of time before another phone call exists (112) the radiotelephone (300) is placed (114) in an off mode. The roam shutoff feature implements a process in which the processor (310) determines (116) if the radiotelephone (300) is in a roam mode. If the radiotelephone (300) is in a roam mode and no phone call exists (118) the radiotelephone is placed (114) in the off mode.

Abstract: A system and method for absolute, high resolution and accurate strain measurement includes a low-coherence light source (12) transmitting light through a strain sensor (18) and into an interferometer (26). The interferometer (26) has a high-coherence light source (48) that parallels the light from the low-coherence light source (12). The output of the interferometer is detected by a photodetector (46). The photodetector (46) is connected to a phase measuring circuit (30), that is in communication with a controller (28). The controller (28) is also connected to a motor (44) that adjusts the optical path lengths in the interferometer (38). The phase change in the high-coherence source from the fringe pattern (68) of the strain sensor (18) before and after a strain is applied to the device under test is used to determine the strain.

Abstract: An assembly machine (10) has a plurality of slots (22) each of which hold a feeder (24) containing a component reel (30). The assembly machine (10) automatically assembles a printed circuit board from these components. When a changeover occurs the assembly machine (10) determines which components need to be added (104), which need to be removed and which can be moved (106). The assembly machine (10) then instructs an operator to first perform all the remove operations, then to perform all the move operations and last to perform all the add operations. A combination of scanning a component ID (32) and a feeder ID (32) verifies the correct component is placed on the appropriate reel (30). The location of reel (30) among the slots (22) is verified by a proximity sensor (28).

Abstract: A communication system has a PCC 101 which receives a data stream from an cordless base station 115 when the PCC 101 is not engaged in a telephone call. The data stream has a repeat indication field 508 and a message field 506 that the PCC 1 01 uses to determine if the message has already been received. If the PCC 101 determines the message was already received, the PCC 101 turns off its receiver 401 for a duration of time slightly less than the message field time. This results in a power savings for the PCC 101.

Abstract: A personal phone expansion system (10) includes a personal base station (12) and a plurality of portable units (18). The personal base (12) is connected to a phone line (16) and provides routing and switching between the phone line (16), the portable units (18), a full duplex speaker phone (24), and a voice messaging system (26). The voice messaging system (26), which is contained within the personal base station (12) provides full voice mail functions. The personal base station (12) communicates with the portable units (18) by radio signals through a wireless interface (32). The portable units (18) can be used as standard cellular telephones when outside the range of the personal base station (12).

Abstract: Radiotelephones often are powered by batteries (12). When a radiotelephone is bumped, the battery (12) can lose electrical contact with the radiotelephone. When power is interrupted (40), a timer is started (42). When the power is reapplied (44), the timer is sampled (46) and compared against a predetermined period of time. If the power was interrupted for a short time, then the radiotelephone is turned on (50). If the power was interrupted for a long time, then the radiotelephone stays off (48). The timer in the circuit is implemented as an RC circuit (26) starts to discharge. If the voltage level falls below Vref, the radiotelephone will not turn on when the power is reapplied.

Abstract: An EMI shielded keypad (10) or switch for a radiotelephone (50) has a non-conductive cover (12) attached to a printed circuit board (PCB) (14). The PCB (14) has a ground pad (20) and a plurality of metal traces (26) on a first surface (16) that attaches to the cover (12). The cover (12) is made of a flexible, preferably clear material, such as mylar and has a dimple (28) centered over the ground pad (20). A bubble (30) is centered over the plurality of conductive traces (26). A conductive coating (32) is selectively applied to the mating surface (34) of the cover (12), so that the conductive coating (32) in the bubble (30) is electrically isolated. By pressing on the bubble (30) electrically contact is established between the plurality of traces (26), thus the bubble and the traces (26) define a switch.

Abstract: The battery charging process of the present invention uses three charging rates. The initial charge rate of C charges the battery (101) until the battery's temperature reaches a certain level (102). The charger then changes to a trickle charge rate of C/8 to finish charging the battery (103). Next, the charger reduces the charging rate to C/40 to maintain the battery's charge (105). The process then monitors the battery's voltage. If the voltage signal has a slope that indicates the battery is being used by an attached device (106), the charging rate is increased to the trickle charge rate to simultaneously power the device and charge the battery.

Abstract: A headset (10) for a radiotelephone (12) has a boom (16) that pivots about a housing (13). The headset (10) has a speaker (20) and a microphone (18). A headset detect circuit (33) determines when the headset connector (24) has been plugged into the radiotelephone's jack (26) and signals the microprocessor (60). The microprocessor (60) then connects the transmitter (68) and the receiver (70) to the headset's microphone (18) and speaker (20). To answer a call the user rotates the boom (16), either clockwise or counter clockwise, which closes a three position switch (30) and sends an off-hook signal (44) to a microprocessor (60).

Abstract: The extended error correction process of the present invention error corrects a data message that has been transmitted a plurality of times. The process first receives the data message at least twice, logically combining the first and second messages received to form an error indication word. The error indication word is then used to locate the error locations in each message after which some of the errors are complemented, depending on the total number of errors found. The message is then decoded and used for transmit power changes, channel reassignment, to release a call, etc.

Abstract: A cellular cordless telephone may receive cellular telephone calls via a cellular telephone system and receive telephone calls on a system having a limited radio coverage area. To reduce the amount of time spent in monitoring the sub-data channel of the limited coverage area system, a timing signal is generated which represents the period of time spent monitoring the radio channel. During the monitoring, a predetermined number of data words transmitted on the limited radio coverage area radio channel system are received. When a first received data word is detected, an allowed monitoring time value is adjusted to be the sum of the value of the timing signal and the product of a determined number of received words to be detected and the time required for each word. This adjusted value of the monitoring time value is compared to the value of the timing signal and when the adjusted monitoring time value equals or exceeds the timing signal value, the monitoring of the radio channel ceases.

Abstract: A dual-mode RF signal power amplifier combining network is comprised of two branches, each having a power amplifier (200 and 201). The first branch contains a non-linear mode power amplifier (200) while the second branch contains a linear mode power amplifier (201). The non-linear mode branch also has an RF switch (210). Both branches are coupled to a common output node (220). The common node (220) is coupled to a filter (107) before going to an antenna (106). The non-linear mode power amplifier (200) operates when an FM signal is to be amplified, while the linear amplifier (201) is biased in an off state. The linear mode power amplifier (201) operates when a digital signal is to be amplified, while the non-linear amplifier (200) is biased in an off state. The RF switch (210) removes the non-linear amplifier (200) from the circuit to prevent loading the on state linear amplifier (201).

Abstract: A radio receiver, and associated method therefor, for generating a baseband signal having signal component portions of time-varying frequencies. The oscillating signal generated by at least one of the local oscillators of down-mixing circuitry of the receiver is modulated by a low-frequency signal thereby to cause the resultant, baseband signal to be comprised of signal component portions of time-varying frequencies. Because the signal component portions of the baseband signal are of time-varying frequencies, attenuation of such signal component portions and resultant distortion of the received signal, as a result of undesirable notches in the frequency response of a radio receiver is avoided.

Abstract: Data transmission with bit synchronism over an unreliable channel is accomplished by assigning a unique number to each data byte transmitted in a data packet. From this unique number, each data bit may be identified at the packet receiver. When a data packet is missing or uncorrected, the missing data bits are identified and a fill data bit is supplied to the data sink at the time each missing data bit would have been supplied.

Abstract: A self service cart system is provided to speed throughput at a check out counter and thus reduce space devoted to check out counters. The cart comprises a bar code scanner for acquiring a price and a description of a product, a security scanner for converting a tag from an unsecured state to a secured state, a magnetic card reader for activating the cart and a controller. The controller stores the price and description of all products in a store and keeps a running total of the price of the products scanned and placed in the cart and coordinates the various activities of the various parts of the cart system. An inventory control computer is connected to the cart's controller at the check out counter to down load the price and description of the products scanned. The products then pass through a security sensor which determines if the products are in the secured state and raises an alarm if the products are in the unsecured state.

Abstract: An error detector circuit and associated method for a digital receiver. The digital receiver is operative in a TDMA communication scheme in which DQPSK-modulated signals are generated, such as the Japanese Digital Cordless Telephone System. The error detector circuit detects times in which an excessive amount of noise or other distortion is introduced upon one or more sequences of a signal transmitted during one or more time slots in the TDMA communications scheme. A receiver incorporating the error detector circuit is operative not to decode portions of a received signal when excessive numbers of sequences include excessive amounts of noise or other distortion introduced thereupon. Thereby, degradation of the audio quality of a signal actually recreated by the receiver incorporating the error detector.