Abstract: The invention provides an optical recording medium, in which data is recording in both a land portion and a groove portion, which can always provide an accurate tracking error signal. In the optical recording medium, pre-pits for pre-format or ID data are formed in an area occupying one part of the groove portion in a transverse direction and in the other area in the transverse direction.

Abstract: A local system issues an ICMP echo request packet with a size based on an initial PMTU value corresponding to that of the local system's interface MTU. When an ICMP needfrag error packet is received by the local system, this signifies that the initial PMTU value was too large for packets of corresponding size to be transmitted through the Internet without fragmentation. The value is accordingly decreased by the local system and a next ICMP echo request packet transmitted through the Internet. The process iterates until an ICMP echo request packet is successfully transmitted through the Internet to a target system. In response thereto, the target system transmits an ICMP echo response packet back through the Internet to the local system, thereby indicating that the last-sent ICMP echo request packet from the local system had the correct PMTU value which is thereafter assumed to be the correct PMTU.

Abstract: A flow control system for packet transmission networks is centered in the user applications supplying data to the network. Changes in control are responsive to changes in the transmission parameters of the network, measured in the network and transmitted to the user application. The user application specifies desired ranges of Quality of Service parameters and, when the measured network parameters fall outside of the desired range, the user application modifies the transmission strategy to match the available transmission parameters. Measurements of network parameters are made over a pre-selected observation period to average the values of the transmission parameters.

Abstract: A transfer layer of an ATM type used between a switch (216) and a number N of communication channels (218). Each communication channel (218) has second storage arrangement B.sub.0, . . . , B.sub.N-1 for storing cell queues having a length of up to P cells each, one of the second storage arrangements being in a busy condition if a minimum number M of cells is stored therein, where M is lesser of equal P. Each communication channel is assigned to one of the switch queues. The transfer layer (217) has third storage arrangement T for storage of a cell queue having a length of up to L cells. Furthermore the transfer layer (217) selectively disables the input of a cell from one of the switch queues into the third storage arrangement if the second storage arrangement is in a busy condition.

Abstract: A testing device for testing telecommunication digital lines referred to as high-cap or T-1 lines by introducing a go/no-go loop back signal to both line sides. The testing device uses a test loop generating controller interface that can be used with any high-cap copper installation with or without line repeaters in place.

Abstract: A full-duplex modem having improved transmission speeds over voice grade telephone circuits that extends the concepts of asymmetric transmission to include echo cancellation techniques. The preferred modem has a high speed forward channel and an overlapping low speed back channel and is capable of transmitting or receiving over either of the channels, depending on the relative data rates. A narrow band echo canceler substantially cancels all or part of reflected transmit signals. Because the echo cancellation technique employed is narrow band, there is a significant reduction in the complexity and computational requirements for the modem.

Abstract: A concentrated subscriber wireless remote telemetry system which uses low-cost remote communication devices operating on existing wireless communication systems in order to provide real-time reading and control of remote devices. The metering system comprises at least one powerline remote metering device which collects and forwards telemetry data to an associated wireless remote telemetry device. The wireless remote telemetry device relays the telemetry data to a central controller over existing wireless communication systems, such as cellular base stations, using existing communication standards. The wireless remote metering device transmits various messages over a shared random access channel to the central controller. The central controller transmits messages to the wireless remote metering unit over a paging channel. The wireless remote metering unit may operate in a half-duplex mode only.

Abstract: A transmission control system for performing one-to-multiple site data transmission by a radio packet communication, comprising a plurality of communication terminals and a communication base station for determining timing of access control as well as timing of sending and receiving transmission data, the communication terminals and the communication base station being connected via a radio packet communication system, in which the communication terminal sends a negative acknowledgment signal on the failure in receiving a packet signal sent from the communication base station, the communication base station resends the packet signal which is not received by the communication terminal upon receipt of the negative acknowledgment signal, and the communication terminal sending the packet signal resends the packet signal which was sent just before, upon receipt of the packet signal resent from the communication base station.

Abstract: A device for transferring binary data between a time-division multiplex and a RAM includes circuitry for assigning, for each time slot of the multiplex, a logical channel number. This enables two HDLC controllers, respectively for transmission and reception, to be shared between all the channels of the multiplex.

Abstract: A collaborative computing system includes a plurality of collaborative computing participants, connected over a network. Each collaborative computing participant has a workstation that includes a conference engine, which provides a network interface between applications and the network. The applications are organized into application modules, each of which provides a collaborative computing function. Either the conference engine or the application modules fragment a data packet to be sent to other participants into a set of equally-sized cells. The cells are transmitted individually over the network via switching entities, which can be other participants in the collaborative session. Each switching entity maintains a list of connections from itself to other switching entities.

Abstract: A buffer control system is a system for implementing both a priority control process and a shaping process of cells with a hardware configuration of a small size in a network routing fixed-length packets which are respectively composed of transfer data and control information added to the transfer data, and to which priority information is assigned, according to the control information. If a cell written to an empty area of a cell buffer is a prioritized cell, and its expected output time is a time slot, an address where the cell is stored in the cell buffer is arranged in a time slot in a prioritized cell entry memory. When it reaches the time to read the cell stored in the time slot, the address stored in the time slot is written to an output list chain, and the cell is read from that address. The empty area of the buffer is managed using a free list chain.

Abstract: An arrangement for supplying local network emulation services over a broad connectionless ATM-network. The ATM-network is in charge of connectionless data communication traffic by a broadband data service network. Private local networks can be connected to the ATM-network to exchange traffic with other local networks. The ATM-network emulates local networks so that the ATM-network can deal with the local network traffic. The broadband data service network includes servers which function as address resolvers for local network addresses and as local network relays for routing local network traffic via the ATM-network. The server uses unit specific addresses and local emulation groups as addresses.

Abstract: A distributed private branch telephone exchange (PBX) including a local area network carrying telephony traffic, an interface to the PSTN and a station interface connecting to a telephone device transmitting telephony over the local area network. The distributed PBX may contain a number of multi-port modules connected over a local area data network. The multi-port modules convert between synchronous and asynchronous signals and connect between a telephony environment, such as a telephone device, a local area network, and a personal computing device. The distributed PBX also includes PBX software and a graphical user interface (GUI) which facilitate the management of various PBX functions.

Abstract: The invention provides a computer implemented system comprised of two computer terminals for effectuating bidirectional digital, time synchronized communications between networks operating asynchronously with respect to one another. The system repackages the data field of a message received from a network into a message that further includes time indicia corresponding to a time slot in which the repackaged message is to be transmitted so that it may be received by a second network. The repackaged message then is buffered until it is transmitted in the the appropriate time slot so that it may be detected by the second network. The invention overcomes the problem of effectuating communications between distant networks where the message propagation time and time slot period for receiving messages limits the range of communications.

Abstract: Arbitration apparatus and method coordinate access to an output of a routing device in a packet switching network. Access to the output is granted to requests having the highest priority in a current arbitration cycle. For requests having the same priority, access is granted to the first of such requests received. Before granting a request, the arbitration apparatus ensures a receiving input buffer has sufficient space for a data packet, as well as any higher priority traffic.

Abstract: For use in a communications network having a source and destination endpoint that employs a video transmission protocol in which the destination endpoint of a video stream receives a release command from the source endpoint of the video stream to begin displaying the video stream, the destination endpoint normally receiving the release command only after completion of a capabilities negotiation between the destination endpoint and the source endpoint, a system for, and method of, multicasting the video stream from the source endpoint to at least one destination endpoint.

Abstract: Received Ethernet MII packets are converted to T1/E1 HDSL frames and received T1/E1 HDSL frames are converted into Ethernet MII packets. When Ethernet MII format 4 bit data packets are received they are converted into 8 bit data packets, each 8 bit data packet having an associated signal bit. For T1, a series of twenty-one 8 bit data packets and associated signal bit are combined with three pass bits into a 192 bit T1 HDSL frame. The series of twenty-one multiple 8 bit packets and associated signal bit with three pass bits are transmitted in HDSL format.When T1 HDSL frames having a series of twenty-one 9 bit packets, each 9 bit packet including 8 data bits with an associated signal bit, and three pass bits, are received, the series of twenty-one 9 bit packets and three pass bits are converted into twenty-one groups of 9 bit packets, each 9 bit packet including an 8 bit data packet with an associated signal bit.

Abstract: The present invention provides a method (300) and system (200) of contention-based multiple access for the reservation subchannel to support a large population of users with diverse QoS requirements wherein users are permitted to transmit reservation messages in reservation slots in a coordinated manner to contend for the privilege to transmit data messages in the data slots. In the event of a collision in the reservation slots, a prioritized contention resolution algorithm is used to resolve the collision.

Abstract: A first data stream for a first data transmission system having a first data rate contains ATM data cells and structural data, which are distributed as spaced apart data in accordance with a specified instruction and are assigned to a section including in each case a plurality of ATM data cells. While retaining its ATM data cell format, the first data stream is converted into a second data stream containing only ATM data cells for a second data transmission system having a second data rate which is higher than the first data rate. The structural data are thereby selected (or picked out) from the first data stream and are input into a marked structural cell having the ATM cell format, for the section. The structural cell is inserted into the second data stream to partially fill an unoccupied section resulting from the differing data rates.

Abstract: System for establishing a TDM information protocol over a communications path includes a transmit section and a receive section. In general, the transmit element receives a succession of data elements from each of a plurality of independent channels and combines the data elements to form a single TDM sequence of data elements. The receive element receives a TDM sequence of data elements and separates the sequence into its constituent components to form a plurality of channels, each forming a succession of data elements. In one form of the invention, data elements transmitted via the TDM communications path are limited to a single time slot in the TDM protocol.

Abstract: A ring network with dual homing connections to the network from one or more nodes via physically separated concentrators.

Abstract: A bidirectional converter/interface for connecting several two-way broadb RF cables to a single pair of optical fibers is provided. In the reception mode, a broadband RF carrier of an optical conductor signal is directed to a plurality of bandpass filter/block converter combinations. These filter/converter combinations segment the broadband RF carrier into predetermined RF bands carrying the information. Each segmented band is then shifted (either up or down) to the receiving band frequency utilized by each of the RF systems. In the transmission mode, each transmitted signal from one of the RF systems is passed to a return path block converter/bandpass filter combination that shifts the entire transmitted band to a predetermined band. The predetermined bands are chosen such that each is a unique, non-overlapping band associated with a particular one of the RF systems.

Abstract: A subchannel within a CDMA signal is provided together with a system for receiving and decoding this subchannel. A message is transmitted over the subchannel by applying a sequence of phase rotations to the user data. A single subchannel message can be transmitted during each 1.25 ms segment of user data, resulting in a transmission rates of up to 800 messages per second over the subchannel. Each message corresponds to a fixed sequence of phases, called a phase codeword, used to rotate the user data each time that message is sent. When only two phase codewords are used, the effective data rate for the subchannel is 800 bits per second, but higher data rates may be achieved by increasing the number of codewords used by the subchannel. The subchannel may be decoded by correlating the user data with each of the possible phase codewords.

Abstract: The device and method according to the present invention permute the order of signals representing information intended for storage in a memory. The signal ordering is permuted prior to or at the time of storage in the memory such that when the information or data is stored in the permuted order, it is more tolerant to errors or defects that existed or may occur in the memory.

Abstract: A semiconductor memory is provided with a select circuit and a control circuit. The select circuit selects either a master clock signal or a test clock signal supplied to a specific terminal, based upon a mode selection signal supplied to a specific terminal. The control operation writes, reads and erases data of the memory cells in response to the master clock signal or the test clock signal. A semiconductor memory test method includes a number of steps, including supplying a mode selection signal, which is higher than normally used voltage, to a specific terminal, and a test clock signal is supplied to another specific terminal; the master clock signal and the test clock signal are then switched in response to the mode selection signal; the data writes and erases relating to the cells of the memory are then tested based upon the test clock signal.

Abstract: A method and apparatus observes a mode register (102) in a synchronous memory device. A multiplexer (306) selects the value of the mode register (102) or the conventional data path of the memory array (302) through the output buffer. The invention outputs the stored value of the control register (102) on output pins, such as address pins when no signal is expected. The multiplexer (306) maybe responsive to a variety of control signals.

Abstract: A circuit for coupling a LIC driver to a IEEE 1149.1 boundary scan implementation includes a logic circuit that converts the data and oe signals of the IEEE 1149.1 specification to test "q.sub.-- up" and "q.sub.-- dn" signals meeting the requirements of the LIC driver. These test "q.sub.-- up" and "q.sub.-- dn" signals are selectively provided to the LIC driver during boundary scan testing of the output driver. In a further refinement, the logic circuit also converts functional q.sub.-- up and q.sub.-- dn signals provided by the circuit under test to the data and oe signals of the IEEE 1149.1 specification. The logic circuit allows the widely used IEEE 1149.1 boundary scan standard to be used with LIC drivers. The resulting compatibility simplifies the testing and use of the LIC drivers, and provides a new boundary scan standard for use with LIC drivers that is compliant with the IEEE 1149.1 standard.

Abstract: A scan test apparatus for operating a test unit according to a test pattern and outputs address information of the test pattern at which a fail takes place, which includes a memory unit for holding circuit information in which scan flip-flops are written at corresponding addresses and a control unit for outputting, in addition to the address information, a scan flip-flop name from the memory unit corresponding to the address information.

Abstract: The present invention provides a method and apparatus for generating parity in a data storage system. The data storage system includes two or more storage devices having data stored therein, two or more data buses through which the data is transferred, and a selector located between the storage devices and the buses which selectively connects the storage devices and the data buses by a predetermined combination. The selector further includes the capability of calculating parity operations such as an XOR operation. The selector performs the parity operations to logically combine data transferred through the selector between the data buses and the storage devices to produce parity data on the combined data transferred so as to reduce the data transfers over the data bus.

Abstract: Arrangements for high output power laser sources and optical fiber amplifiers are disclosed. In one arrangement, an optical fiber section which is doped with erbium, is coupled with one or two mirror elements, such as fiber Bragg gratings, to form a DBR or DFB fiber laser. The optical fiber section receives energy at one end from a pumping laser and lases at one or more selected wavelengths. This output light, along with energy from the pumping laser, is transmitted through the second end of the optical fiber section to an erbium-doped fiber amplifier, which boosts the laser output even higher. The gain of the optical fiber section may be further increased by co-doping the section with erbium and ytterbium. With co-doped optical fiber sections, high power output fiber optical amplifiers and laser sources, in the form of DBR and DFB fiber lasers, which can accept the pumping energies of a plurality of pumping lasers, can be created with properly selected WDM coupler and WDM coupler/isolator devices.

Abstract: A laser includes a split-wave hybrid resonator that produces a high quality laser beam from a low gain laser medium. The split-wave hybrid resonator includes a resonator cavity formed by a pair of resonator mirror surfaces positioned at opposite ends of the laser medium and a pair of resonator walls positioned on opposite sides of the resonator cavity. The resonator walls are separated from each other by a separation distance such that the resonator cavity has a Fresnel number between approximately 0.5 and 1.5. At least one of the resonator walls includes a first ring oscillation filter adjacent to the lasing medium to filter out ring oscillations within the laser medium. One or more of the resonator walls may include first and second wall portions angled with respect to each other to form a wave-front splitting interferometer. The resonator mirrors are tilted off-axis with respect to the resonator walls.

Abstract: A laser includes a laser head and a power supply. At least two resonator mirrors define a resonator cavity. A gain medium is positioned in the resonator cavity. A temperature controller is positioned in the laser head and is coupled to the gain medium. The temperature controller maintains the gain medium at a temperature of 25 degrees C. or greater. A pump source supplies a pump beam to the gain medium and producing an output beam. The power source is coupled to the pump source.

Abstract: The present invention provides a n-drive surface emitting laser comprised of an active region, a first mirror region having a first conductivity type, a second mirror region having a second opposite conductivity type, the first and second mirror regions being located on opposite sides of the light generation region, a buffer region having a second conductivity type, and a substrate having a first conductivity type. In the preferred embodiment the first conductivity type is n-type, thus the present invention provides a method of forming an n-drive semiconductor laser on an n-type substrate. Contact is made to the p-type mirror region via a tunnel junction formed by degeneratively doping the areas of the substrate region and the buffer region which abut each other. The tunnel junction is reverse biased so that current is injected through the degeneratively doped p-n junction formed by the n+ substrate and the p-type conducting layer.

Abstract: A semiconductor laser includes a lower cladding layer, an active layer, a first upper cladding layer, an etch-stopping layer, a second upper cladding layer, and a contact layer successively laminated on a substrate, a ridge waveguide formed by selectively etching the second upper cladding layer and the contact layer with the use of a stripe-like insulating film as a mask to form a ridge, an AlAs oxide layer on the substrate and a second electrode on the substrate. Incorrect positioning does not occur between the ridge waveguide and a first electrode, reliability is improved, and the distribution of effective refractive index transverse to the resonation of the laser is reduced. A detailed method of fabricating this semiconductor laser is also provided.

Abstract: An improved intracavity sensor based output power control for microcavity light emitting devices. An improved phototransistor transducer is both configured and physically disposed so that it passively transmits the spurious optical energy output of the microcavity light emitting device while simultaneously generating a light determined electrical signal of easily used large magnitude that is nearly free of error. The base-collector region of the transistor is disposed with a quantum well absorbing layer and produces a signal responsive to a selected emission wavelength. The configuration of the optical energy communicating transducer is arranged so that it is improved in sensitivity and especially in selectivity in generating the laser feedback signal.

Abstract: A substantially n-type substrate structure having a p-type surface for use in semiconductor devices as a substitute for a p-type semiconductor substrate. The substrate structure comprises a substrate region and a buffer region. The substrate region is a region of n-type compound semiconductor, and includes a degeneratively n-doped portion adjacent its first surface. The buffer region is a region of compound semiconductor doped with a p-type dopant. The buffer region is located on the first surface of the substrate region and includes a surface remote from the substrate region that provides the p-type surface of the substrate structure. The buffer region also includes a degeneratively p-doped portion adjacent the degeneratively n-doped portion of the substrate region. The substrate structure includes a tunnel junction between the degeneratively n-doped portion of the substrate region and the degeneratively p-doped portion of the buffer region.

Abstract: A gas laser includes an enclosure forming a first chamber, a second chamber and a lasing chamber which communicates through a first opening to the first chamber and through a second opening to the second chamber. The lasing chamber has a pair of reflectors defining a Fabry-Perot cavity. Separate inlets enable different gases to be introduced into the first and second chambers. A first cathode within the first chamber is provided to produce positive ions which travel into the lasing chamber and a second cathode of a pin-hollow type within the second chamber is provided to produce negative ions which travel into the lasing chamber. A third inlet introduces a molecular gas into the lasing chamber, where the molecular gas becomes excited by the positive and negative ions and emits light which lases in the Fabry-Perot cavity.

Abstract: A solid-state laser apparatus comprises a plurality of solid-state materials each having an active solid-state medium and arranged in a row with a predetermined space on an optical axis of light incident thereon. An optical rotation material and an angle adjusting instrument for adjusting an angle between the optical rotation material and the optical axis of incident light are disposed in at least a space selected from among the plural spaces. The laser apparatus further comprises a laser optical system for extracting a laser beam emitted by the plural solid-state materials.

Abstract: A cold crucible induction melting furnace is provided with a plurality of segments separated by a plurality of slits that surround a bottom member which together form the melting chamber. Each lower end of each segment is overlapped with and spaced from a short part of a vertically extending side wall of the bottom member so as to form a horizontal gap there between. A radially and outwardly extending flange protrudes from the bottom member side wall below each segment lower end to form a lower gap there between. An induction coil is disposed around and spaced from an outer face of the segments with a lower end adjacent to each of the lower segment ends and an upper end adjacent to an upper part of each segment that is in turn connected with an adjacent upper segment part to form a short circuited part.

Abstract: A high-speed variable length decoding apparatus independently generates a run-level symbol and decodes the run-level symbol, to thereby variable length decode the variable length coded data at high frequency for signal processing. The variable length decoding apparatus includes a storage and output portion for storing the variable length coded data and outputting the stored variable length coded data by a predetermined data amount in response to a data storage state signal, a run-level table for outputting a run-level symbol which is determined by the data output from the storage and output portion, a memory for storing and outputting the run-level symbol output from the run-level table, in a first-in-first-out manner, and generating the signal indicating a data storage state of its own, and a run-level decoder for run-level decoding the run-level symbol output from the memory.

Abstract: A cordless direct sequence spread spectrum telephone using a direct conversion radio architecture wherein the code sequence used for spreading and despreading is an even code sequence to prevent addition of low frequency noise in the down-conversion process, the preferred even code being a 12-chip code and, more particularly, being an even 12-chip code that is generated by adding one bit to an inverted, shifted, and/or reversed 11-chip Barker sequence.

Abstract: A communications system including a primary station and at least one or more secondary stations. The secondary station transmits signals as spread spectrum signals and a receiver in the primary station receives and decodes the spread signals. Frequency offsets in the received spread spectrum signals are dealt with by digitizing the received signals to produce raw data samples which are despread, frequency analyzed and the spectrums derived are scanned for peaks exceeding a predetermined threshold and the outputs indicate the presence or absence of codes.

Abstract: Known is a digital communication system comprising wireless terminals for voice and non-voice data communication. In order to get a flexible mixed voice and non-voice data communication system terminals for mixed real time voice and reliable non-voice data communication are provided in which set-up channels are dynamically assigned to non-voice or to mixed voice and non-voice communications without first releasing the assigned communication resources. Herewith, at a higher level layer such as an application layer very fast switching over is achieved while other devices in the system are fully unaware of such switching over. In multimedia communications, such a fast switching over is particularly advantageous.

Abstract: A telecommunication system for transmission along power supply lines of modulated information signals having a selected carrier frequency. The system includes a plurality of communication devices connected along the supply lines, each including a microcontroller and a modem. The modem includes an interface module which establishes a link to the power supply lines for modulated information signals, a transmission module which contains a digital modulator followed a digital/analog converter, and a receiving module. The receiving module includes a digital filter connected between an analog/digital converter and a digital demodulator. The digital filter is adapted to the carrier frequency of modulated information signals present on the power supply lines, whereby the modem can operate at any selected frequency over a broad frequency range.

Abstract: The function addressed is that of adaptive equalization to mitigate the effects of multiple path radio propagation in the context of point-to-multipoint, time division duplexed microwave radio systems. Without this equalization, fading and intersymbol interference degrades the accuracy of the recovered bit stream. This degradation of the received signal is caused by the vector sum of multiple copies of the transmitted signal arriving with various time offsets and amplitudes. The method employed uses a single training symbol per frame common for all time division multiplexed derived channels rather than one for each channel and for both up and down directions. Compensation is applied at each station transmitter rather than separately equalizing each received signal at the common receiver.

Abstract: A data and clock recovery circuit includes a front end circuit for receiving a data signal encoded with a Manchester or other bi-phase level code having a sequence of bit frames, and for outputting a recovered data signal and a recovered clock signal in accordance with transitions in the data signal that overlap with a window signal. A window generation circuit generates the window signal in accordance with a delay control signal, and includes circuitry that delays and transforms the recovered clock signal into the window signal. A delay control circuit generates and adjusts the delay control signal. A phase comparison circuit compares the recovered clock signal with leading and lagging portions of the window signal, and generates signals that adjust the delay control signal when the recovered clock signal overlaps with either of the leading and lagging portions of the signal.

Abstract: A modulated clock MSK modulator that separately modulates a sinusoidal clock signal by square wave I and Q digital data signals prior to the I and Q data signals being modulated onto a carrier wave signal. Mixers or applicable biphase switches are utilized to impress the I and Q digital data signal information onto the clock signal by inverting or non-inverting the clock signal on separate I and Q data rails to create I and Q modulated clock signals separated in phase. The I channel data modulated clock signal and the Q channel data modulated clock signal are then separately applied to a conventional quadraphase modulator to be separately modulated onto a carrier wave signal, and the summed together to be transmitted.

Abstract: The invention relates to a method in connection with a QAM receiver wherein, particularly when making use of a 32QAM, 64QAM demodulator lator a like, a digital transmission signal (1) to be transmitted is down-converted in a tuner and band-filtered with a first filter to a preferably fixed, standard intermediate frequency (5). This is followed by a further subsequent down-conversion by a first oscillator and filtering with a second filter to a so-called low intermediate frequency (6) which is equal to the symbol rate used in image transmission or its low odd multiple, whereafter an AD converter (7) is used under the synchronization of a second oscillator (8) for picking up samples (X) from the symbol sequence of a processed signal (6) to a demodulator (9), capable of regulating the above-mentioned, preferably voltage-controlled oscillators.

Abstract: A pre-amplifier circuit, which may be used in a variety of data recovery circuits to accurately recover data transmissions, includes an input regulatory circuit, a feedback circuit, and an amplifier. The input regulatory circuit regulates the magnitude of the data signal provided to the amplifier based on feedback signals from a feedback circuit. For low level data signals, the input regulatory circuit provides a full, or almost full, representation of the data signal to the amplifier for amplification. But, when the data signal levels increase, the input regulatory circuit attenuates, based on the feedback signals, the data signals more and more before providing them to the amplifier, such that the output of the amplifier stays within a certain range.

Abstract: A limited search variant of the fixed delay tree search detector is used to recover digital signals corrupted with intersymbol interference and additive noise. The limited search algorithm uses a variant of an equalizer decision device--a simple slicer--to reduce the number of paths that are considered by the tree search detector from M.sup.D+1 to either D+1 or 2.sup.D+1 paths, thereby significantly reducing the complexity of the tree-search detector. This limited search detector enjoys negligible loss in performance, compared with that of a full fixed delay tree search.