Abstract: A method and system is disclosed which provides a multi-data rate demodulator for a communication system. The present invention 10 demodulates and extracts a data signal from a received analog signal. A baseband signal is extracted by filtering and downconverting the received analog signal. The baseband signal is sampled and converted to a digital signal, providing a digital word corresponding to each sample. A digital filter provides a sum of the digitized samples over a programmable symbol time corresponding to the signal data rate. The data signal is then extracted by processing the sums of the digitized samples.
Abstract: An improved symbol synchronization circuit is provided for generting a clock signal in a receiver having an input signal comprising a stream of symbols at a symbol rate of f.sub.symbol. According to the invention, a correlator is provided that operates on a multiplicity (k) of multi-phase signals, .phi..sub.1 -.phi..sub.k, each signal more or less synchronized with the stream of symbols and each having a frequency f.sub.clock generally equal to a multiple of f.sub.symbol. Based on the current synchronization of each signal .phi..sub.1 -.phi..sub.k with the stream of symbols, and also based on the past history of the synchronization of each signal with the stream of symbols, one member from the group of signals .phi..sub.1 -.phi..sub.k is periodically selected as the clock signal. This selected clock signal is then delayed to compensate for the drift between f.sub.symbol and f.sub.clock.
Abstract: The invention enables extremely quick and reliable recovery of the synchronization of a communication signal transmitted in a half-duplex link. Such a communication signal comprises first time intervals including useful data, and second time intervals devoid of useful data and in a given logic state. At the beginning of each of the first time intervals is included a digital synchronization pattern which is then considered as associated with the second time intervals to form synchronization words of great length. The synchronization of the communication signal is recovered by detecting the synchronization words of great length in the communication signal.
August 16, 1989
Date of Patent:
September 3, 1991
L'Etat Francais represente par le Ministre des Postes, des Telecommunications et de l'Espace (Centre d'Etudes des Telecommunications)
Abstract: Circuit arrangement for digitally setting the gain factor of a digitally adjustable receive amplifier. For digitally setting the gain factor of a digitally adjustable receive amplifier independently of the reception signal, the circuit arrangement for positive and negative reception signals amplified by the gain factor has comparators whose outputs are fed back via respective feedback switching network to a comparison input of the respective appertaining comparator. As a result of the feedback switching networks the signal level at each of the comparison inputs has different comparison values which are dependent on the signal levels at the output of the respective comparator. Whenever the signal level of the reception signal exceeds one of the comparison values, a counter, that may be a non-linear counter, is decremented by one step and thereby provides a counter reading indicating the gain.
Abstract: A matrix circuit has a plurality of blocks each including a plurality of semiconductor unit elements, the semiconductor unit elements of each block being adapted to be impressed with a predetermined voltage at the same time, each unit element becoming active when impressed with the predetermined voltage, and a drive device for impressing the predetermined voltage to the plurality of blocks sequentially. The matrix circuit includes a first selective device for selecting either ground or a desired other than ground voltage, and a second selective device for selecting one of the output of the drive device and the output of the first selective device whereby the output of the second selective device renders active the plurality of unit elements of each block.
Abstract: An electronic remote chemical identification system is described, in which a transponder for recording information regarding the contents and other information of a railroad tank car, highway tank truck or other container is placed thereon, the transponder being coded remotely with the information by a remotely located, fixed or portable encoder and interrogated when desired by a remotely located, fixed or portable interrogator unit. In the case of an accident, emergency and other response personnel can utilize the interrogator to query a single or a plurality of transponders on the tank cars in the train or on the tank truck to safely and immediately ascertain the exact contents of the containers and other associated information regarding the shipper, the origin and destination of the consignment, shipper's emergency personnel telephone number and proper response action to be taken at the accident scene, etc.
Abstract: The period of time that the squelch circuit maintains a radio receiver's audio amplifier active after the signal strength of a received carrier fades below a threshold level is inversely proportional to the strength of the received carrier immediately before the fade. This threshold level is also variable. If, immediately before the fade, the received signal strength exceeds a predetermined trigger level (Vtrg) the threshold level is raised. A buffer amplifier (102) charges a capacitor (C) to a voltage which is proportional to the strength of a received carrier. If the carrier fades below a threshold (Vth2 or Vth3, the buffer is disabled and the capacitor slowly discharges through a resistor (R). When the voltage at the capacitor crosses a reference voltage (Vref1) the output of a comparator (104) switches, thereby deactivating the receiver's audio amplifier.
Abstract: An interconnection device in the form of a programmable integrated crosspoint switch includes a matrix of first and second pluralities of electrically conductive paths, e.g. an M line by N line matrix, and selectively permanently and affirmatively programmable switch elements for completing passive conductive circuit paths between one or more of the conductive paths of such first and second pluralities thereof. The programmable integrated crosspoint switch invention may be utilized in various hierarchical levels of interconnection.
October 17, 1988
Date of Patent:
August 14, 1990
Ohio Associated Enterprises, Inc.
Rod Schwartz, John T. Venaleck, Kenneth W. Braund
Abstract: In a radio communication network system for use in carrying out communication with a plurality of radio telephone sets in a service zone by the use of a control channel and a plurality of speech channels, a connecting equipment unit (CE) is selectively operable in cooperation with a radio control unit (RCU) in a speech mode of forming a speech path through a selected one of the speech channels and an additional mode of selectively monitoring the control and the speech channels. The additional mode may be divided into first and second control modes for allowing and rejecting reception of a call with the control channel monitored, respectively. Alternatively, either a rest mode or a combination of rest and initial program loading modes may be added to the additional mode. A plurality of the connecting equipment units may be located in a single service zone and selectively put into the speech and the additional modes with only one of the connecting equipment units kept in the first control mode.
May 31, 1988
Date of Patent:
July 3, 1990
Nippon Telegraph and Telephone Corp., Matsushita Communication Industrial Co., Ltd., NEC Corp.
Abstract: An FM receiver capable of generating a signal showing the electric field intensity of a received signal. More particularly, an FM receiver capable of generating a signal showing the electric field, wherein the dynamic range is expanded, and the linearity is improved. The enlargement of the dynamic range of the signal showing the electric field intensity may be effected, and also the linearity may be improved. Accordingly, the electric field intensity of the received signal may be correctly displayed by a display, etc. Especially, as the gain control is effected through the control of the operation current of the gain control amplification circuit in accordance with the gain control signal by the differential type of level detection circuit, an FM receiver suitable for IC may be provided.
Abstract: Configurable semiconductor integrated circuits as-made each have a plurality of logic circuits formed at discrete sites. For each logic circuit, direct selectably conducting/non-conducting connection paths extend from its output to input of a first set of other logic circuits and to its inputs from outputs of a second set of other logic circuits. All of the sets for all of the logic circuits are each different. Other direct connection paths are selectably connectable to inputs and outputs of the logic circuits. Selection can be irreversible or reversible and involves coincident signal addressing of the sites and coded configuring of the paths at that site. Reversible selection can be via field effect transistors or bipolar transistors and can be at or near normal logic signal levels and speeds. Versatile configurable input/output arrangements are described also reconfigurable data processing systems using the reversible transistor provisions.
Abstract: A computer aided dispatch system is provided for use in a trunked communication system. The system comprises at least a master file node and a plurality of user nodes. The master file node contains a data record for each subscriber on the trunked communication system. Each data record has a plurality of fields that may assume various values. Each dispatcher "attaches" to a particular value of at least one field in any of the data records. The master file node maintains the records for each subscriber and automatically transmits an updated record to each dispatcher attached to the subgroup in which the subscriber operates. In this way, dispatchers are continuously provided the latest subscriber status even though the responsibility for monitoring the status of a particular subscriber unit may dynamically pass from dispatcher to dispatcher.
December 11, 1986
Date of Patent:
May 15, 1990
Richard A. Comroe, Richare H. Coe, Katherine B. Roane, Lewis H. Rosenthal
Abstract: Programmable logic cells, and arrays of those cells, having certain characteristics, including: (1) the ability to program each cell to act either as a logic element or as a logical identity element(s) between one or more inputs and one or more outputs; (2) the ability to rotate circuits by 90.degree. and to reflect circuits about horizontal and vertical axes; (3) an integrated logic and communication structure which emphasizes strictly local communications; (4) a minimal complexity of logic functions available at the cell level, making available a very fine-grained logic structure; and (5) suitability for implementation of both synchronous and asynchronous logic, including speed-independent circuits. Cells are arranged in a grid, with each cell communicating with its north, east, west and south neighbors. The cells are programmable to several states.
Abstract: A data communication apparatus comprises means for registering a destination station identification code number, means for storing information, and control means for setting a communication mode by the destination station identification code registration means and the information storing means.
Abstract: A microphone is provided in which two circuit boards are held in spaced parallel position by each being connected at one end to a supporting member and by each resting at the other end in a pair of stabilizing grooves located within the microphone head. A battery holding assembly has attached at one end the supporting member, and at the other end an antenna mounting surface onto which a coiled antenna is placed. A battery holding compartment is located between the supporting member and the antenna so that a battery held in the compartment acts as an addition to the antenna itself. A power and battery level indicator flashes on and off to warn that the charge of the battery is reaching a predetermined low point. The electronic circuitry for the indicator is also provided.
Abstract: A television tuner for three frequency ranges (I, II, III) comprises a common antenna connection (4) for corresponding input filter circuits. The input filter circuits (1, 2, 3) of the two higher frequency ranges can be connected to and disconnected from the antenna connection by means of switches (11, 12). The switches (11, 12) are each located between the antenna connection (4) and the associated input filter circuit (2, 3). To improve matching of the input filter circuit (3) and to simplify the configuration of the circuit, the antenna connection (4) is arranged in the proximity of an input filter circuit (1, 2) of the two lower-frequency frequency ranges (I, II). In addition, the switch (12) for the highest frequency range (III) is connected to the end of a coupling conductor (5) which is spaced closest to the antenna connection (4).
Abstract: The printed circuit board system and method are characterized by the use of at least one integrated circuit path bridging device, preferably a programmable integrated crosspoint switch, mounted to a printed circuit board for enabling electrical interconnection or circuit paths to cross over other electrical interconnection or circuit paths whereby a single plane or surface interconnection system can be given multi-plane interconnection potential or a multi-plane interconnection system can be given increased interconnection potential, while avoiding or minimizing drawbacks associated with multi-plane circuit interconnection systems such as need for plated through holes and relatively high cost.
Abstract: A synchronous transmission system that improves reception in areas where the main and the satellite signal create significant self interference. At least one of the synchronous transmitters is phase modulated in accordance with a selected modulation function which varies at a sub sonic rate.
Abstract: An improved FM communication system is disclosed in which noise bursts and pops in the audio output of the receiver, due to weak and Rayleigh-faded signals, are minimized by selectively attenuating the audio signal in the receiver. The amount and rate of attenuation for the receiver noise reduction circuits is determined by a control signal derived form either the average discriminator noise at frequencies above 3 kHz, or from a received RF signal strength indicator, or a combination of both. The audio output is attenuated during weak signals or Rayleigh fades only when the attenuation control signal increases above a predetermined signal-to-noise ratio threshold. Also described are further improvements to noise attenuation devices used in combination with the receiver noise reduction circuits to enhance audio quality in particular applications, e.g., FM repeater systems which may incorporate multiple transmitters in a simulcast configuration.
Abstract: A signal substitution system for cable television applies substitute television program signals in at least one substitute channel to the transmission cable along with signal substitution control signals. The signal substitution control signals include a plurality of different terminal command signals and a plurality of different event command signals. Each of the terminal command signals includes a respective panelist address signal for identifying a respective panelist receiving station and a plurality of event identification signals identifying respective events. Each of the event command signals includes a respective event address signal corresponding to a respective event and a normal channel identification signal for identifying a normal channel into which a substitute television program is to be switched. A controller at each panelist receiving station responds to the signal substitution control signals by selectively switching a substitute television program into a normal channel.