Abstract: The present invention presents an apparatus and method for recovering symbols in a data packet (101) transmitted to a receiver from a remote signal source (204) in a time-varying channel using multiple sampling points. In a digital cellular radiotelephone TDMA system, the receiver (202) performs a complex correlation on the desired slot sync word (DSSW) and the coded digital verification color code (CDVCC) in the data packet (101), and on the adjacent slot sync word (ASSW) in an adjacent data packet (102) to produce a first, second and third optimum sampling point, respectively. The data packet (101) is divided into four regions (A, B, C and D). The symbols in each region (A, B, C and D) are serially recovered using one or more of the multiple sampling points depending on the quality of the sampling point adjacent to each region (A, B, C and D).

Abstract: The present patent application includes a discussion of a signal compensation apparatus (119). The apparatus is implemented in a digital radiotelephone (101) having diversity receivers (111, 113). The signal compensation apparatus utilizes three control loops and a branch selection switch circuit to substantially diminish the undesired gain and DC offset present in the selected received data signal. Portions of the apparatus are implemented in a digital signal processor (DSP) (249) for rapid adjustment of the control loops when switching to a different receiver branch.

Abstract: In a communications device, two coherent detection algorithms (102 and 103), one of which has a decision feedback equalizer (103), and a detector selection algorithm (104) are used to dynamically select a detector depending on whether delay spread distortion is present. First the correlation of the detector without the equalizer (102) is measured. If this correlation is greater than a predetermined threshold, the data from that detector (102) is used by the communications device. If the correlation is less than the threshold, the correlation of the detector with the equalizer (103) is measured. If this is less than the correlation of the detector without the equalizer (102), the data from the detector without the equalizer (102) is used, otherwise the data is taken from the equalizer (103).

Abstract: A differential quadrature PSK receiver (100) recovers serial data in a forward and reverse direction in time using a forward and reverse mode PLL (232) and decoder switch (108). The DQPSK receiver (100) is particularly useful for recovering a packet of serial data (Rx) having a time-varying signal level and a relatively long duration. Sync words in the packet (Rx) or adjacent packets (Ry) provide starting points from which the data is recovered. The direction in time of data recovery is dependent on the quality of the time-varying signal level in the packet (Rx).

Abstract: A system for facilitating link continuity and prompt supervisory control in a communication system with discontinuous transmissions comprising varying the carrier power in a first communication unit and varying frequency deviation of a modulating signal to provide a continuous signal detectable by a second communication unit, where continuous monitoring at the second communication unit allows for rapid detection and reaction to received supervisory control signals through the use of continually comparing the received supervisory signal to an expected signal and qualifier signal to enhance the reaction time of the second communication unit.

Abstract: A gate lifter for shifting a gate from a valve seat in a gate valve. The gate lifter is provided on the downstream, or low pressure side of a valve, and is a tubular structure that surrounds and is slidable relative to a tubular valve seat. Hydraulic or other pressurized fluid is adapted to be introduced between an end of the lifter and a flange carried by the valve seat to cause the parts to move in opposite directions, as a result of which the lifter operates by shifting the gate member away from the valve seat to avoid damage to the valve seat as the gate member is moved there across. The gate lifter includes a face that is adapted to engage with a corresponding face of the gate member, the gate lifter face preferably including a low friction coating, such as teflon, gearings or gearing type material.

Abstract: The method of the present invention provides fast frequency acquisition in a PLL. The peak voltage for a phase error signal is detected at time t.sub.p and a voltage controlled oscillator warp voltage is sampled at t.sub.p. The new warp voltage to the voltage controlled oscillator is set to what the warp voltage was at t.sub.p. The bandwidth of the loop is then narrowed and the warp voltage is averaged over a number of samples. The warp voltage is then set to the average warp voltage and the loop bandwidth is widened.

Abstract: The .pi./4-QPSK coherent detector of the present invention has a vector input and an output comprising recovered data in bit pair form. The .pi./4-QPSK coherent detector recovers bursts of data, in a TDMA system, that has been encoded in an amplitude modulated vector's phase angle. The .pi./4-QPSK coherent detector detects the .pi./4-QPSK constellation of the incoming modulated signal and outputs the recovered data stream.

Abstract: An antenna switch control circuit for use in achieving antenna selection diversity in TDM RF receivers. RSSI for at least one antenna is monitored during time slots containing information not of interest. This information can then be compared with other antenna performance information to allow a selection to be made such that the receiver generally operates with the antenna receiving the strongest signal. In one embodiment, all possible antennas are monitored during a time slot containing information not of interest. In another embodiment, RSSI for the selected antenna can be monitored during the time slot of interest, such that antenna selection can again be varied should the selected antenna diminish in performance.

Abstract: The transmission and reception of burst analog signals, such a voice signal, over a TDM system is improved according to the present invention by minimizing discontinuities between the signal at the end of its time slot in one frame relative to the beginning signal at its next time slot in the following TDM frame. In the TDM transmitter, stored digital information transmitted during its time slot is reprocessed during the preceding time slot in the next frame in order to maintain magnitude continuity. In the TDM receiver, the feedback signal to an analog to digital conversion circuit is switched during non-active time slots to follow data being clocked out of a digital storage element at a frame rate such that the data clocked out preceding the next active time slot will correspond to the data present at the end of the preceding active time slot.

Abstract: The connector comprises means (2) defining a bore (4) to receive a bared end portion or portions (20) of an optical fibre cable (16), the means (2) being surrounded by a body (12) of sealant material and a member (10) of heat recoverable material. After insertion of the cable or cables, (16) the member (12) is recovered and compresses the sealant material (10) into intimate contact with the means (2) and cable or cables (16).

Abstract: A time division multiplexed (TDM) communication device controller is disclosed, which controls all signalling, synchronization and supervisory functions. In one embodiment, the invention operates to control a remote communication device having a vo-coder and buffering means. The remote communication device is enabled to operate as a dispatch, full duplex or a combination dispatch/full duplex communication device. In another embodiment, a primary station (repeater) is controlled to operate as a single frequency repeater (SFR) or as a multi-frequency TDM repeater.

Abstract: An optical fiber termination of the expanded beam type in which the fiber end fits into one end of a glass ferrule whose other end is closed by a spherical lens. The ferrule is filled with an ultra-violet curing glue. The position of the fiber end is adjusted so that light from the fiber leaves the lens as a collimated beam and then the glue is cured by ultra-violet light injected, initially, via the lens to cure the glue at the fiber end and lens. Then the rest of the glue is cured by ultra-violet light applied through the wall of the ferrule.

Abstract: A reaction type flux and the method utilizing same in the soldering of aluminum containing products, particularly aluminum-zinc coated ferrous sheet and strip products. Said flux comprising a mixture consisting essentially of, parts by weight, 10 to 14 stannous chloride, 0.25 to 1.5 ammonium chloride, and 0.05 to 0.3 sodium fluoride. Such a flux mixture is characterized by a reaction temperature in the anhydrous condition of less than about 470.degree. F., preferably below about 450.degree. F., thereby permitting the application of electric iron techniques in the soldering operation.