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Showing papers by "Motorola published in 1993"


Journal Article•DOI•
Moe Rahnema1•
TL;DR: The global system for mobile telecommunications (GSM), which provides terminal mobility, with personal mobility provided through the insertion of a subscriber identity module (SIM) into the GSM network, is discussed.
Abstract: The global system for mobile telecommunications (GSM), which provides terminal mobility, with personal mobility provided through the insertion of a subscriber identity module (SIM) into the GSM network, is discussed. Cellular mobile communications, the cellular network infrastructure, and the specification of network databases and standards are described. The GSMs, numbering plan, radio channel structure, mobility management, call routing and signaling, protocol layering architecture, signaling transport protocols, and paging messaging systems are also described. >

509 citations


Journal Article•DOI•
TL;DR: Research on the consensus problem is surveyed, approaches are compared, applications are outlined, and directions for future work are suggested.
Abstract: The consensus problem is concerned with the agreement on a system status by the fault-free segment of a processor population in spite of the possible inadvertent or even malicious spread of disinformation by the fault segment of that population. The resulting protocols are useful throughout fault-tolerant distributed systems and will impact the design of other decision systems to come. This paper surveys research on the consensus problem, compares approaches, outlines applications, and suggests directions for future work.

428 citations


Patent•
John Richard Kane1•
30 Aug 1993
TL;DR: In this article, a paging terminal (102) is coupled to an electronic mail network (113) for receiving the electronic mail messages, storing the received electronic mail message including alias identification (208, 210) of the originating devices of the e-mail messages, and encoding messages including the message data and the alias of the received e-mails for transmission to at least one selective call receiver (130).
Abstract: An electronic mail message delivery system (100) includes an electronic mail network (113) for delivering electronic mail messages from originating devices to destination devices, the electronic mail messages including network addresses (212) for identifying originating and destination devices communicating the electronic mail messages, and including message data (214). A paging terminal (102) is coupled to the electronic mail network (113) for receiving the electronic mail messages, storing the received electronic mail messages including alias identification (208, 210) of the originating devices of the electronic mail messages, and encoding messages including the message data and the alias of the received electronic mail messages for transmission to at least one selective call receiver (130). A paging transmitting means (124, 126) transmits the encoded messages over a paging communication channel, and at least one portable selective call receiver (130) can receive the transmitted messages. Optionally, the at least one portable selective call receiver (130) can transmit a reply message through the paging terminal (102) to an originating device on the electronic mail network (113).

351 citations


Patent•
Jon T. Fitch1, Papu D. Maniar1, Keith E. Witek1, Jerry Gelatos1, Reza Moazzami1, Sergio A. Ajuria1 •
02 Jun 1993
TL;DR: In this article, a method for forming an air region or an air bridge overlying a base layer (12) is described, where air regions (20a, 20b, 28a, and 48) are formed by either selectively removing a sacrificial spacer (16a and 16b) or by selectively removing another sacrificial layer (28, 40).
Abstract: A method for forming an air region or an air bridge overlying a base layer (12). Air regions (20a, 20b, 28a, and 48) are formed overlying the base layer (12) to provide for improved dielectric isolation of adjacent conductive layers, provide air-isolated conductive interconnects, and/or form many other microstructures or microdevices. The air regions (20a, 20b, 28a, and 48) are formed by either selectively removing a sacrificial spacer (16a and 16b) or by selectively removing a sacrificial layer (28, 40). The air regions (20a, 20b, 28a, and 48) are sealed, enclosed, or isolated by either a selective growth process or by a non-conformal deposition technique. The air regions (20a, 20b, 28a, and 48) may be formed under any pressure, gas concentration, or processing condition (i.e. temperature, etc.). The air regions (20a, 20b, 28a, and 48) may be formed at any level within an integrated circuit.

347 citations


Patent•
29 Nov 1993
TL;DR: A Global Positioning System (GPS) communications includes a GPS receiver for generating position information, a processor coupled to the GPS receiver by a bus, and a communications multi-interface coupled to both the GPS receivers and to the processor by the bus as discussed by the authors.
Abstract: A Global Positioning System (GPS) communications includes a GPS receiver for generating position information, a processor coupled to the GPS receiver by a bus, and a communications multi-interface coupled to both the GPS receiver and to the processor by the bus. The processor presents the position information to the communications multi-interface capable of interfacing with a wide variety of communications systems. Described applications include guided weapons systems, interrogatable tag systems, collision avoidance systems, remote locator/responder systems, beacon location systems, search and rescue transceiver systems, location reporting pager systems, and cellular telephone location systems.

315 citations


Patent•
Frank Djennas1, Victor K. Nomi1, John R. Pastore1, Twila J. Reeves1, Les Postlethwait1 •
04 May 1993
TL;DR: A wire bondable plastic encapsulated semiconductor device having no die supporting surface can be manufactured in this paper, where the die is rigidly held in place on a workholder with a vacuum for the wire bonding process.
Abstract: A wire bondable plastic encapsulated semiconductor device (58) having no die supporting surface can be manufactured. In one embodiment, a semiconductor die (22) and a plurality of conductors (12) extending toward the periphery of the die are provided. The die is rigidly held in place on a workholder (60) with a vacuum (62) for the wire bonding process. Wire bonds (26) electrically connect the die to the conductors. The wire bonded die is then placed inside a mold cavity (64), and a resin encapsulated is transferred into the cavity under elevated temperature and pressure to form package body (70) around the die, the wire bonds and a portion of the conductors. Before the package body is formed, the die is supported solely by the the rigidity of the wire bonds since there is no die supporting surface connected to the conductors.

292 citations


Patent•
Robert E. Penny1, Thomas J. Mihm1•
22 Apr 1993
Abstract: A hand-portable position locating radio has a geolocation (e.g. GPS) receiver providing local position and timing information from geolocation means (e.g. GPS or IRIDIUM satellites) and a local transceiver for sending local position and other information to a communication system (e.g., an IRIDIUM or MILSAT satellite). A data processor coupled to the local transceiver and receiver controls operation of the device, including storing local position information and separating signals broadcast by the communication system into those intended or not intended for the device. The radio prepares an emergency access message which it sends to the satellite communication system in a manner to insure rapid detection of the emergency signal and allocation of a clear channel and time slot for further communication.

267 citations


Patent•
18 Oct 1993
TL;DR: Time slots may be allocated within a communication system when a communication unit transmits a first packet to a time slot allocator as discussed by the authors, which determines whether the first packet contains a request for allocation of n-time slots or a request to transmit multiple packets.
Abstract: Time slots may be allocated within a communication system when a communication unit transmits a first packet to a time slot allocator. Upon receiving the first packet, the time slot allocator determines whether the first packet contains a request for allocation of n-time slots or a request to transmit multiple packets. When the first packet contains the request for allocation of n-time slots, the time slot allocator allocates the n-time slots to the communication unit when the n-time slots are available, wherein the n-time slots are allocated contiguous in time. When the first packet contains the request to transmit multiple packets, the time slot allocator allocates time slots to the communication unit until the multiple packets have been transmitted, wherein the time slots are allocated contiguous in time.

245 citations


Patent•
Jose Gutman1, G. Rasor1•
06 Jul 1993
TL;DR: In this article, a portable vibratory alerting device (20, 30) is part of a resonant system and has a vibrator (60) for both generating a vibrational alert and sensing the resonant frequency of the system.
Abstract: A portable vibratory alerting device (20) is part of a resonant system (20, 30) and has a resonant vibrator (60) for both generating a vibrational alert and sensing the resonant frequency of the resonant system. The vibrator (60) is driven by a variable frequency driver (76, 78), and thereafter the resonant frequency is measured by a sensor (82). A vibration controller (72) causes the frequency of the vibrator to be substantially equal to the resonant frequency of the system. Alternately, a portable alerting device (520) has both a vibrator (160) and a sensor (166) for sensing the amplitude of a vibratory alert at various frequencies. A vibration controller (72) generates a vibratory alert at an optimum frequency in response to the sensed amplitudes.

234 citations


Patent•
03 Sep 1993
TL;DR: A flow formed encapsulated integrated circuit package (100) includes a printed circuit substrate (160) having upper and lower opposed surfaces and one or more anchor holes (150) as discussed by the authors.
Abstract: A flow formed encapsulated integrated circuit package (100) includes a printed circuit substrate (160) having upper and lower opposed surfaces and one or more anchor holes (150) The one or more anchor holes (150) have an upper aperture in the upper surface and a lower aperture in the lower surface One or more integrated circuit die (130) are electrically and mechanically attached to the upper surface of the substrate (160) In addition, a solder resist mask (190) is attached to the lower surface of the substrate which covers the aperture of the one or more anchor holes (150) Flow formed material (110) is formed around the integrated circuit die (130) so as to encapsulate the one or more integrated circuits (150), the flow formed material (110) covering at a least a portion of the upper surface of the printed circuit substrate (160) and extending substantially into the anchor hole (150)

221 citations


Patent•
12 Oct 1993
TL;DR: A transponding tag with two antennae formed on opposing sides of a dielectric planar substrate is shown in this article, where an electrical circuit, decoupling capacitor and inductive pickup coil are embedded within the substrate.
Abstract: A transponding tag (14) and method for responding with a unique code signal (18) when it receives an interrogation signal (16) The tag (14) waits a random duration before responding to avoid interference with response code signals (18) from other tags (14) The tag (14) includes two antennae (22, 24) formed on opposing sides of a dielectric planar substrate (20) A protective coating (52) and printed indicia (72) overlie the antennae An electrical circuit (34), decoupling capacitor (44) and inductive pickup coil (46) are embedded within the substrate (20) The electrical circuit (34) and capacitor (44) reside between the antennae (22, 24) to receive RF shielding from the antennae and to reduce thickness of the tag (14) A capacitance exists between the antennae (22, 24) This capacitance stores DC electrical energy for the electrical circuit (34) The tag (14) is programmed through a modulated magnetic field detected at the inductive pickup coil (46)

Patent•
08 Nov 1993
TL;DR: In this article, a selective call receiver (106) receives one or more message packets of a transmitted fragmented message, where each of the message packets includes an address (1605) and message data (1610), and the message data includes an indication (1702) of whether more messages are to be received for the fragmented message.
Abstract: A selective call receiver (106) receives one or more message packets of a transmitted fragmented message, where each of the one or more message packets includes an address (1605) and message data (1610), and the message data (1610) includes an indication (1702) of whether more message packets are to be received for the fragmented message. The selective call receiver (106) receives an address of each message packet, and then correlates (2908) the address to one or more predetermined addresses. After a successful correlation (2908), the selective call receiver (106) decodes the message data (1610) of each message packet, and then successively stores (2928, 2936, 2942) the decoded message data (1610) to reconstruct the fragmented message. The selective call receiver (106) determines that the fragmented message is completely reconstructed after detection (2918) in the decoded message data (1610) an indication (1702) that no more message packets are to be received for the fragmented message.

Patent•
01 Dec 1993
TL;DR: In this paper, the authors propose a stacked IC chip arrangement, which consists of a first IC chip and a second IC chip, each having an array of terminals and being positioned in a face-to-face manner.
Abstract: An integrated circuit package includes a stacked integrated circuit chip arrangement (140) placed on a circuit substrate. The stacked IC chip arrangement includes a first IC chip (110) and a second IC chip (120), each having an array of terminals (116, 126) and being positioned in a face-to-face manner. An interposed substrate (130) is positioned between the first IC chip (110) and the second IC chip (120) such that circuitry disposed on the interposed substrate (130) provides electrical connection among the arrays of terminals of the first IC chip (110) and the second IC chip (120) and external circuitry.

Journal Article•DOI•
J.Z. Wang1•
TL;DR: It is shown that in the proposed UPCS system, the maximum database size is 0.51% and the database updating cost is 6.86% of that needed by a central database system under a specified scenario.
Abstract: The universal personal communication system (UPCS) is a system that enables anyone to communicate instantly with anyone else anywhere in the world. One of the crucial problems of such a system is locating hundreds of millions of moving portables in an efficient manner. The location registration strategy described is able to locate active portables automatically in the system with a small overhead in a distributed fashion. The system knows the exact position of an active portable in its service areas. The connection is set up by the system directly to its destination using the direct (shortest) path. The system capacity, efficiency, and inquiry time delay have been improved greatly compared to the leading existing techniques. It is shown that in the proposed system, the maximum database size is 0.51% and the database updating cost is 6.86% of that needed by a central database system under a specified scenario. >

Patent•
01 Jun 1993
TL;DR: In this paper, a timing signal is generated which represents the period of time spent monitoring the radio channel and when the adjusted monitoring time value equals or exceeds the timing signal value, the monitored radio channel ceases.
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.

Patent•
21 Jun 1993
TL;DR: In this article, a wireless infrared communications system (100) for communicating packetized information (302) between a Control Module (12) and a plurality of User Modules (14) via infrared transceivers (300/320) and having a selectable communications path is presented.
Abstract: A wireless infrared (IR) communications system (100) for communicating packetized information (302) between a Control Module (12) and a plurality of User Modules (14) via infrared transceivers (300/320) and having a selectable communications path. In this system at least the User Modules (14) have a plurality of IR device arrays (A1-A6) for receiving IR signals (312/312') in relatively narrow IR field of view sectors, and a selector (20), coupled to said plurality in IR device arrays (A1-A6), for selecting a communication path between the Control Module (12) and one of said plurality of IR device arrays (A1-A6), based at least partly on received signal (302') integrity, so as to overcome reception errors caused by multipath interference.

Patent•
22 Mar 1993
TL;DR: In this paper, a lead frame is used to support a semiconductor die to alleviate package cracking problems caused by stress and to provide a universal lead frame which is suitable for use with many different die sizes.
Abstract: A semiconductor device (10) includes a lead frame (12) having tie bars (16). In one form of the invention, the tie bars are used to support a semiconductor die (20) to alleviate package cracking problems caused by stress and to provide a universal lead frame which is suitable for use with many different die sizes. In another embodiment, a semiconductor device (45) includes a lead frame (40) having a mini-flag (42) to accomplish these same objectives.

Patent•
29 Nov 1993
TL;DR: In this article, a radio transmitter (100) that includes a power amplifier (104) and an antenna (106) can be enhanced by using a variable matching network (VN).
Abstract: In a radio transmitter (100) that includes a power amplifier (104) and an antenna (106), a method for enhancing an operating characteristic of the radio transmitter (100) can be accomplished in the following manner. The power amplifier (104) provides a signal (113) to a variable matching network (111), wherein the signal (113) comprises energy to be radiated by the antenna (106). The variable matching network (111) couples the signal (113) to a sampler (112) that is operably coupled to an output of the variable matching network (111 ) and the antenna (106). The sampler (112) samples a forward component (114) and a reflected component (115) of the signal (113). The radio transmitter (100) processes the sampled forward and reflected components (116, 118) to produce a feedback control signal (120). The feedback control signal (120) is used to adjust the variable matching network (111 ), such that an operating characteristic of the radio transmitter (100) is enhanced.

Patent•
27 May 1993
TL;DR: In this article, the RF tag reader detects the resonant frequencies of the decoder RF resonant circuits and determines the one decoding modality, and then the tag reader determines the predetermined number from the decoding modalities to confirm the accurate detection of the data RF resonance circuits.
Abstract: An RF tagging system includes an RF tag (10, 30) and an RF tag reader 80. The RF tag includes a plurality of RF resonant circuits. Each RF resonant circuit is resonant at a given RF frequency. A group of decoder RF resonant circuits (12, 32) have resonant frequencies defining one of a plurality of predetermined decoding modalities. A group of data RF resonant circuits (14, 34) have resonant frequencies corresponding to a predetermined identification code when the resonant frequencies of the data RF resonant circuits are decoded in accordance with the one decoding modality. The RF tag reader detects the resonant frequencies of the decoder RF resonant circuits and determines the one decoding modality. The RF tag reader is operative in each of the plurality of predetermined decoding modalities, detects the resonant frequencies of the group of data RF resonant circuits, and decodes the resonant frequencies of the group of data RF resonant circuits in accordance with the one decoding modality to provide the identification code. The decoder RF resonant circuits may also indicate the number of data RF resonant circuits on the RF tag. The RF tag reader determines the predetermined number from the decoder RF resonant circuits to confirm the accurate detection of the data RF resonant circuits. The RF tag reader, when selecting a decoding modality in accordance with the detected resonant frequencies of the decoder RF resonant circuits, determines various frequency bands and alters the RF tag reader frequency detection operation for accurate detection of the data RF resonant circuits.

Patent•
Leo M. Higgins1•
01 Mar 1993
TL;DR: In this paper, an area array semiconductor device with functional I/O contacts can be manufactured, where a die is mounted in a die cavity of a substrate and a plurality of wire bonds connect the die to conductive traces on a surface of the substrate.
Abstract: An area array semiconductor device (10) having a lid with functional I/O contacts can be manufactured. In one embodiment, a semiconductor die (12) is mounted in a die cavity (16) of a substrate (14). A plurality of wire bonds (20) connect the die to conductive traces (18) on a surface of the substrate. A lid (22) having conductive traces (26) on an inner surface, which are electrically interconnected to an area array of contact pads (28) on an outer surface by a plurality of plated through-holes (30), is attached to the substrate with an anisotropic conductive adhesive (32). The adhesive electrically connects the conductive traces on the substrate to the conductive traces on the lid. A plurality of conductive pins (34) are attached to the area array of contact pads to provide one method of mounting the device to a board.

Patent•
02 Dec 1993
TL;DR: In this article, the home access network of a subscriber unit with a home access number is provided for wireless local loop radiotelephone systems by providing the home APN to the subscriber unit for storage there.
Abstract: Mobility is provided for wireless local loop radiotelephone systems by providing the home access network of a subscriber unit with a home access number. Upon registration of the subscriber unit with its home access network, the home access number is transmitted to the subscriber unit for storage there. When the subscriber unit moves to a visited access network and registers there, the subscriber unit transmits the home access number to the visited access network, which uses the home access number to contact the home access network. Since all call originations and terminations by and to the subscriber unit occur via the individual subscriber line appearance at the PSTN, a minimum of special network elements are required for subscriber unit mobility when the home access number is stored at the subscriber unit.

Patent•
12 Oct 1993
TL;DR: In this paper, a lead frame is used to support a semiconductor die to alleviate package cracking problems caused by stress and to provide a universal lead frame which is suitable for use with many different die sizes.
Abstract: A semiconductor device (10) includes a lead frame (12) having tie bars (16). In one form of the invention, the tie bars are used to support a semiconductor die (20) to alleviate package cracking problems caused by stress and to provide a universal lead frame which is suitable for use with many different die sizes. In another embodiment, a semiconductor device (45) includes a lead frame (40) having a mini-flag (42) to accomplish these same objectives.

Patent•
24 Sep 1993
TL;DR: A hierarchical communication network includes primary, secondary, and tertiary communication systems as discussed by the authors, where the primary system uses orbiting satellites as communication nodes and forms a pattern of cells that may cover the entire earth and that move over the earth.
Abstract: A hierarchical communication network includes primary, secondary, and tertiary communication systems. The primary system uses orbiting satellites as communication nodes and forms a pattern of cells that may cover the entire earth and that move over the earth. A given spectrum is divided among the cells in accordance with a reuse plan. Any number of secondary, terrestrial-based systems have secondary region areas of coverage that are substantially smaller than the distance to the orbits of the satellites used by the primary system. Secondary systems monitor the primary system to determine which channels of the spectrum are available for use in their secondary regions. Any number of tertiary, terrestrial-based systems reside within a secondary region and have tertiary region areas of coverage that are substantially confined within buildings. Tertiary systems use channels concurrently used by the primary system in the same area where their tertiary regions are located.

Patent•
Bruckert Eugene1•
03 Mar 1993
TL;DR: In this paper, a spread-spectrum noise cancellation method was proposed to cancel a portion of a spread spectrum noise signal in the received signal (200) by generating an estimated signal (270) by spreading (260) the second known signal at the second component received phase (204) with the first known signals at the first component receiving phase (224) and adjusting a gain (268) of an integrated form of the spread second signal as a function of the received amplitudes of the first (216) and the second (236) components.
Abstract: A spread-spectrum noise canceller (182) is provided. A received phase and a received amplitude for a first (216) and a second (236) component of a received spread-spectrum signal (200) is determined. The second component (236) is structurally similar to [a replica of] the first component (216), but differs by being received at a different time, being transmitted along a different path, or having a different phase [which was received at a different time]. In addition, the spread-spectrum signal (200) includes a first and a second known signal. A portion of a spread-spectrum noise signal in the received signal (200) is canceled by generating an estimated signal (270) by spreading (260) the second known signal at the second component received phase (204) with the first known signal at the first component received phase (224) and adjusting a gain (268) of an integrated form of the spread second known signal as a function of the received amplitudes of the first (216) and the second (236) components. Subsequently, the second known signal is processed out of the received spread-spectrum signal (200) by subtracting (166) the estimated signal (270) from a demodulated form (216, 236) of the received spread-spectrum signal (200).

Patent•
01 Nov 1993
TL;DR: In this article, the flexible substrate (11) is configured in a U-shaped configuration having at least one rigidizer plate (25, 41, 42) positioned in the notch of the U, and a low modulus adhesive layer is utilized in the assembly to minimize thermal stress.
Abstract: Semiconductor carrier assemblies (10, 40) use a flexible substrate (11) to connect to at least one semiconductor device (19) Preferably the flexible substrate (11) also connects to a circuit component, preferably a circuit board (31) The flexible substrate (11) is configured in a U-shaped configuration having at least one rigidizer plate (25; 41, 42) positioned in the notch of the U Interconnections between the semiconductor device (19) and the flexible substrate (11), and, preferably, the circuit component (31) are provided by solder connections (22, 28) Preferably, two rigidizer plates (41,42) having different temperature coefficients of expansion are positioned in the notch of the U of the flexible substrate (11) and preferably a low modulus adhesive layer (50, 51, 47) is utilized in the assembly to minimize thermal stress

Patent•
13 Sep 1993
TL;DR: A copper metallization structure and process for the formation of electrical interconnections fabricated with pure copper metal is provided in this article, which includes an interface layer (22) intermediate to a dielectric layer (12), and a copper interconnect (30).
Abstract: A copper metallization structure and process for the formation of electrical interconnections fabricated with pure copper metal is provided. The metallization structure includes an interface layer (22) intermediate to a dielectric layer (12), and a copper interconnect (30). The interface layer (22) functions to adhere the copper interconnect (30) to a device substrate (10) and to prevent the diffusion of copper into underlying dielectric layers. The interconnect layer (22) is fabricated by depositing a first titanium layer (16) followed by the sequential deposition of a titanium nitride layer (18), and a second titanium layer (20). A copper layer (24) is deposited to overlie the second titanium layer (20) and an annealing step is carried out to form a copper-titanium intermetallic layer (26). The titanium nitride layer (18) functions as a diffusion barrier preventing the diffusion of copper into the underlying dielectric layer (12), and the copper titanium intermetallic layer (26) provides an adhesive material, which adheres the copper layer (24) to the device substrate ( 10). Following the formation of the intermetallic layer (26), the device surface is planarized to form a planar surface (28), and to form an inlaid copper interconnect (30).

Patent•
21 Jan 1993
TL;DR: In this paper, the authors propose to use test-only leads and operational leads to reduce the overall lead pitch of a semiconductor device, enabling the device to be made very small.
Abstract: A semiconductor device (10) includes test-only leads (20) and operational leads (18). Operational leads (18) provide access to portions of a semiconductor die (12) needed for device operation. Test-only leads (20) provide access to portions of die (12) which are not needed for device operation, but which are needed during manufacturing tests. Operational leads (18) have an external configuration which facilitates attachment to a user substrate. Test-only leads (20) have an external configuration which enables electrical access to the device for test purposes; however, the test-only lead configuration makes attachment to the user substrate difficult. Since the test-only leads (20) and the operational leads (18) have two different external lead configurations, overall lead pitch is reduced, enabling device (10) to be made very small. Yet, complexity of mounting device (10) to a user substrate is not increased since the pitch between adjacent operational leads (18) can be made larger than the overall lead pitch.

Patent•
Barry J. Menich1, Jeffrey D. Bonta1•
27 Jan 1993
TL;DR: In this paper, a handover target selection method for a communication unit (40) exchanging a communicated signal through a serving base site (10-19) in a digital cellular system is proposed.
Abstract: A method of selecting handover targets for a communication unit (40) exchanging a communicated signal through a serving base site (10-19) in a digital cellular system. The method uses timing advance to determine a relative distance of a communication unit (40) to the serving base site (10-19). The method comprises the steps of comparing a timing advance value with a first threshold. The first threshold may be equal to a distance one and one-half times the radius of the serving cell. When the timing advance value exceeds the first threshold, a base site frequency list is modified to include base sites non-adjacent the serving base site. The identity of the base sites non-adjacent the serving base sites may be determined from the directionality of communication unit (40). The method further includes the step of selecting a handover target providing highest relative RRSI value to the communication unit (40) from the modified base site frequency list.

Patent•
26 Apr 1993
TL;DR: In this paper, a heat spreader with conductive traces and conductive pads is used to spread heat from a semiconductor die to a substrate, which is then covered by a cavity sealing means.
Abstract: A package (10, 37, 39) capable of spreading heat from a semiconductor die (25). The package (10, 37) includes a heat spreader (11) having a thickness of approximately 0.2 millimeters and a plurality of heat spreader clearance holes (16). The heat spreader (11) is coated with an adhesive material (17) which fills the plurality of heat spreader clearance holes (16). A substrate layer (18) is formed on the adhesive material (17). The substrate layer (18) has conductive traces (20, 24) and conductive pads (21) disposed thereon. A cavity (23) may be present in the package (10, 37, 39) which exposes a portion of the heat spreader (11) and is adapted to receive the semiconductor die (25). The cavity (23) is covered by a cavity sealing means (30, 38).

Patent•
Robert C. Ledzius1, James S. Irwin1•
15 Jan 1993
TL;DR: In this paper, a finite impulse response (FIR) filter is used to reduce the noise in the sigma-delta digital-to-analog converter (DAC) passband.
Abstract: A sigma-delta digital-to-analog converter (DAC) (40) receives oversampled input data representative of an analog signal. The data may be optionally interpolated to a higher rate in a interpolator (41). A noise-shaping sigma-delta modulator (42) is connected to the output of the interpolator (41). The output of the modulator (42) is provided to a finite impulse response (FIR) filter (43). The FIR filter (43) has a frequency response characteristic which reduces the shaped noise and aliased components. This noise has a tendency to intermodulate back into the DAC's passband. The FIR filter (43) uses a series of flip-flops (81, 82, 83) functioning as delay elements with well-controlled timing edges. The outputs of the flip-flops (81, 82, 83) control current sources (91, 92, 93) weighted according to corresponding filter coefficients. The outputs of the current sources (91, 92, 93) are then summed in a summing device such as an amplifier (101).