Abstract: A technique includes, in response to feedback received from ongoing link training with an endpoint device over a serial communication link, a processor identifying a first training set sequence to be communicated as part of the ongoing link training. The technique includes the processor selecting a first state machine of a plurality of state machines; and the processor programming the selected first state machine to communicate the first training set sequence to the serial communication link. The programming of the first state machine includes programming the first state machine with a data pattern that is associated with the first training set sequence and programming the first state machine with a condition to regulate a number of times that the state machine communicates the data pattern to the serial communication link.

Abstract: Systems and methods can provide a switch mode that is similar to “boot in progress”, but that is admin (e.g., administrator) controllable. This mode can ensure that an admin can perform re-cabling and cable test operations for any single switch in an operational subnet (e.g., an InfiniBand subnet) without causing unnecessary subnet re-routing and re-configuration operations.

Abstract: Certain aspects of the present disclosure provide methods and apparatus for spatial reuse for neighboring nodes of distribution networks, so they may transmit without causing interference to nodes of the distribution network.

Abstract: A system for use in testing a local area network (LAN) cabling system having a LAN cable communicatively coupled to a pair of sockets. The system includes a first LAN testing device that is adapted to exchange test communication signals with a second LAN testing device through the LAN cabling system and a cable communicatively coupled to the first LAN testing device having a plug sized and arranged to communicatively couple with a one of the pair of sockets. The plug includes a switch device and an indicator device that are communicatively coupled to the first LAN testing device via the cable.

Abstract: The disclosure provides a network device and an auto detecting method for automatically detecting direct link between communication devices. In an aspect, the auto detecting method includes following steps. A first network device sends a first signal having a specific pattern from a first network port of the first network device to a second network port of a second network device through a cable network. The first network device determines whether the first network port receives a second signal having the specific pattern from the second network device. When the first network device receives the second signal having the specific pattern from the second network device, the first network device determines that the first network port directly links to the second network port of the second network device; otherwise the first network device determines that the first network device lacks a direct link to the second network device.

Abstract: An embodiment according to the present invention, with respect to a method for a device-to-device (D2D) UE for transceiving a signal, comprises the steps of: receiving a D2D communication resource configuration; and transmitting a D2D communication signal on the basis of the D2D communication resource configuration, wherein if the UE transmits a D2D communication signal by means of a resource indicated by a base station, then the D2D communication signal is transmitted in a first timing determined from a value indicating a timing offset between uplink and downlink radio frames (NTA), and if the UE selects a resource which will transmit the D2D communication signal, then the D2D communication signal is transmitted in a second timing determined without regard to the value indicating the timing offset between the uplink and downlink radio frames (NTA).

Abstract: A method applied to a wired network including a first network device and a second network device is disclosed. The first and second network devices each include a first set of connection ends and a second set of connection ends. Firstly, the first network device transmits a specific signal pattern through its first set and second set of connection ends. Then, the first network device detects whether a signal is received at its first set and second set of connection ends. If it is determined that a signal is not received at the first set connection ends while a signal is received at the second set connection ends, the first network device determines that its second set of connection ends is not correctly coupled to the second set of connection ends of the second network device.

Abstract: A method for modulating data for transmission within a communication system. The method includes establishing a time-frequency shifting matrix of dimension N×N, wherein N is greater than one. The method further includes combining the time-frequency shifting matrix with a data frame to provide an intermediate data frame. A transformed data matrix is provided by permuting elements of the intermediate data frame. A modulated signal is generated in accordance with elements of the transformed data matrix.

Abstract: Systems, methods, and devices for analyzing a network topology are described herein. For example, one or more embodiments include receiving data from a node in a node array with a locating device, determining a position of the locating device, determining a position of the node in relation to the locating device based on the data received from the node and the position of the locating device, comparing the position of the node to a defined layout of the node array, and determining whether the position of the node matches a defined position in the defined layout of the node array.

Abstract: A method and apparatus that secures a dynamic virtualized network is described. In an exemplary embodiment, a device learns a current network policy of the dynamic virtualized network, where the dynamic virtualized network is a virtualized layer 2 network that is overlaid on a layer 3 physical network. In addition, the current network policy includes multiple network policy elements, where each of the multiple network policy elements identifies an authorized endpoint in the dynamic virtualized network. Furthermore, the layer 3 physical network includes multiple network access devices. The device further determines a network security policy for the dynamic virtualized network from the current network policy. The network security policy includes one or more second network policy elements that are a different network policy element than one of the multiple network policy elements of the current network policy.

Abstract: Audio content distribution from audio sources to client terminals through a network. An audio source interface receives raw audio from an audio source, and converts it into a digital audio clip in a digital audio packet, containing a timestamp and a channel identity corresponding to the audio source. A network audio server formats the digital audio packet into a network compliant digital audio file, which is stored at a network address. The network audio server generates a directory packet including the address of the digital audio file, the channel identity, and the timestamp, and, couples the directory packet to a directory server located on the network. The directory server outputs directory packets to a client terminal on the network, which selects a directory packet and sends an audio file request through the network for the digital audio file. The audio file is then sent to the client terminal.

Abstract: A method of transmitting and receiving data frames using pulses is disclosed. According to the transmitting method, a first signal is transmitted including one or more bursts of pulses during a first portion of a transmission frame, and not transmitting the first signal during a second portion of the transmission frame. The not transmitting the first signal may include maintaining one or more silence periods for the second portion of the transmission frame, or transmitting a second signal distinct from the first signal. According to the receiving method, a signal including one or more bursts of pulses is received during a first portion of a transmission frame, an analysis of the one or more bursts of pulses is performed, and the transmission frame is detected based on the analysis of the one or more bursts of pulses.

Abstract: Routes stored by routers in a network that uses the border gateway protocol may be limited to a default route. A device may set, a first route in a routing table, advertised using BGP by a first predetermined network, to be a default route for the device. The device may block forwarding of second routes, advertised using BGP, when the second routes do not correspond to the default route.

Abstract: In an example embodiment, a method and system to provide aggregated alarm indication signals is provided. In example embodiments, an affected intermediate node detects a signal failure. A list of affected networks is determined, and a single aggregated alarm indication signal (AIS) message is generated per MEG level. The aggregated AIS message is then multicast to affected nodes. Instead of sending one AIS message per affected network, a single aggregated AIS message from the affected intermediate node may be generated and sent regardless of the number of affected networks.

Abstract: Systems and methods for the pulse edge modulation of digital carrier signals for communications systems. A digital carrier signal is generated and the carrier is pulse edge modulated with digital data. A pulse edge modulated signal is generated by either retarding or advancing each pulse edge of a carrier to be modulated relative to its original position in time, depending on the state of the digital bit to be modulated on that edge.

Abstract: A communication apparatus (100) includes: a communication unit (10) connectable to one end of a cable (50); a first detection unit (111) which detects a maximum transmission capability of an external device based on a communication standard with which the external device complies, the external device being connected to an other end of the cable (50) connected to the communication unit (10); a second detection unit (112) which detects a maximum transmission capability of the cable (50) connected to the communication unit (10); and an alert output unit (114) which outputs an alert when the maximum transmission capability of the cable (50) is smaller than the maximum transmission capability of the external device, the maximum transmission capability of the cable having been detected by the second detection unit (112), and the maximum transmission capability of the external device having been detected by the first detection unit (111).

Abstract: A novel receiver structure is proposed for detecting a time-hopping ultra-wide bandwidth signal in the presence of multiple access interference. The proposed structure achieves better bit error rate performance than the conventional matched receiver when operating in multiple access interference. When operating in a multiple access interference-plus-Gaussian-noise environment, the receiver structure outperforms the conventional matched filter receiver for moderate to large values of signal-to-noise ratio. A receiver structure with adaptive limiting threshold is further proposed to ensure the performance of the soft-limiting receiver always meets or surpasses the performance of the conventional UWB receiver for all values of signal-to-noise ratio.

Abstract: Audio content distribution from audio sources to client terminals through a network. An audio source interface receives raw audio from an audio source, and converts it into a digital audio clip in a digital audio packet, containing a timestamp and a channel identity corresponding to the audio source. A network audio server formats the digital audio packet into a network compliant digital audio file, which is stored at a network address. The network audio server generates a directory packet including the address of the digital audio file, the channel identity, and the timestamp, and, couples the directory packet to a directory server located on the network. The directory server outputs a directory stream to a client terminal on the network, which selects a directory packet and sends an audio file request through the network for the digital audio file. The audio file is then sent to the client terminal.

Abstract: The present invention concerns a receiver and a method for retrieving data from Ultra wideband radio transmission signals received by a receiver and transmitted in packets containing at least a preamble known to the receiver and a payload containing data unknown to the receiver. The payload data is formed of at least one burst containing at least one pulse. The method comprises the steps of receiving a signal corresponding to the preamble of a packet by a receiver; determining the energy of the received signal; determining weighting coefficients from the energy of the received signal; receiving a signal corresponding to the payload of a packet by a receiver; determining the energy of the received signal; calculating a threshold depending on the weighting coefficients; and applying a decision rule based on the sampled energy, weighted by said weighting coefficients and depending on said calculated threshold.

Abstract: Provided are transmitter topology, receiver topology and methods for generating and transmitting a radio signal at a transmitter and detecting and processing a radio signal at a receiver. The radio signals are transmitted across a wireless interface using Ultra Wideband (UWB) pulses. A transmitted reference approach is utilized. The radio signal include pairs of UWB pulses with each pair of pulses separated by a fixed time delay. The two pulses are then combined to provide for improved noise immunity.

Abstract: Whitespace devices can use unused television frequencies for transmission and reception of WiFi OFDM signals. Three contiguous bands, such as former channels 2, 3, and 4, may be bonded together to define a whitespace band. In order to fit a WiFi OFDM signal into this whitespace band, a whitespace device compresses the bandwidth of each WiFi OFDM signal using a specific spectrum mask. Very low transmission power is needed for the modified WiFi OFDM signals, eliminating the need for high power amplifiers and most of the WiFi OFDM designs such as PHY and MAC can be reused with minor modifications.

Abstract: A technology for rescuing an object when a failure occurs in a redundant system. In a synchronization memory, an instance of an object, which includes the virtual function discrimination information for discriminating a memory area where a virtual function corresponding to the object is stored, the class information for discriminating a class corresponding to the object, and the object data to be used for the processing of the object, is stored according to the order of the processing. In a function memory, plural kinds of virtual functions generated for each process to be carried out by the object are stored. When the object of a new active server reproduces the process, the class corresponding to this object is discriminated using the class information, and the virtual function discrimination information of this object is rewritten.

Abstract: A wireless network device comprises a first wireless communication device that includes a first radio frequency (RF) transceiver that generates a synchronization pulse and that transmits and receives data according to a first period. A second wireless communication device receives a signal indicative of the synchronization pulse and includes a second RF transceiver that transmits and receives data according to a second period. The second period is not equal to the first period and the second wireless communication device adjusts the second period according to the first period and the synchronization pulse.

Abstract: Object To reduce deterioration of transmission quality under circumstances where the moving speed is high. Overcoming Means An adaptive modulation control apparatus for adaptively selecting a modulation parameter from among a plurality of modulation parameters determined based on a plurality of modulation schemes, coding rates of error correction or a combination thereof corresponding to a propagation path state is provided with a reception state measuring section (2) that measures a reception state of a signal received from a communicating apparatus, a correcting section (3) that makes a correction to change propagation path information indicative of a measurement result of the propagation path state based on the measured reception state, and a modulation parameter selecting section (4) that selects a modulation parameter corresponding to the corrected propagation path information.

Abstract: A method and system enables the selective addressing of groups of broadcast receivers within part of a satellite footprint. It uses two satellites having a common transmission band to transmit respective signals, and at receivers in the footprint the phases of the signals received from the two satellites are compared. This phase difference is dependent upon receiver location, but by measuring phase difference no absolute timing or phase measurement is required. A common key is generated at the receivers in a certain area. The output of selected receivers is fed back to the broadcast control centre and is used to encode the location-based services for that area. Preferably the operation is conducted on multiple frequencies and in multiple rounds of such frequencies. A multibit keyword can be directly generated at the receivers by use of a discrete Fourier transform (DFT) and combining its outputs for different rounds.

Abstract: A method, system and type of database for transmitting data is disclosed in which the data is organized into a structured linear database. The structured linear database includes a routing header portion, a file allocation table, a data portion and a tailbit portion. The structured linear database may be transmitted over any type of network, such as a TM-UWB system or a fiber-optic system. Once the data to be transmitted is identified, a corresponding field is identified in the field allocation table giving the location of the data within the transmission. This field is then referenced by the user to access the specific type of data desired at the given location of the transmission. this process may be repeated enabling data to be stored on transmission lines and accessed at any point at any time providing an always on network.

Abstract: A method is disclosed for tuning each channel of a high-speed SerDes cable link interface arranged in a configuration linking a local side physical layer to a remote side physical layer. The method includes initiating an operational state of high-speed SerDes cable link interface, identifying flow-control packet Op codes not cited for use by operational high-speed SerDes cable link interface, transmitting a flow control signal from the local side physical layer to the remote side physical layer to control the remote side physical layer to monitor the eye characteristics of the channels used by the local side physical layer to transfer data to the remote side physical layer, transferring eye characteristics acquired in the monitoring to the local side physical layer and processing the eye characteristics by the local side physical layer to generate equalization setting adjustments.

Abstract: A system samples data of a digital pulse. The system includes a processor, an integrator, and a converter. The processor computes a discrete Fourier transform of frequency data of the digital pulse. The discrete Fourier transform includes a first output. The integrator integrates the first output to produce phase data. The phase data includes a second output. The converter applies an inverse discrete Fourier transform to the second output to produce a continuous signal that may be sampled at a predetermined time instant.

Abstract: In one embodiment, a circuit is provided that includes: an impulse generator operable to provide a pulse train; a pulse position modulator having a splitting junction configured to receive the pulse train, the pulse position modulator including a plurality of n transmission lines, wherein n is an integer, the n transmission lines being selectably coupled in parallel between the splitting junction and a combining junction, the impulse generator driving each transmission line having a unique delay such that if the transmission line is selected, each pulse received at the splitting junction is uniquely delayed into a delayed pulse, whereby if all the transmission lines are selected, each pulse received at the splitting junction is uniquely delayed into a corresponding plurality of n delayed pulses; and a controller operable to select the transmission lines responsive to received words of n bits in length, each word arranged from a first bit to an nth bit, and wherein the transmission lines are arranged from a fi

Abstract: In one embodiment, a wafer scale radar antenna module (WSAM) is provided that includes: a substrate; a plurality of antennas adjacent the substrate; an RF feed network adjacent the substrate, the RF feed network coupling to a distributed plurality of amplifiers integrated with the substrate, wherein the RF feed network and the distributed plurality of amplifiers are configured to form a resonant network such that if a timing signal is injected into an input port of the RF feed network, the resonant network oscillates to provide a globally synchronized RF signal to a plurality of integrated antenna circuits, wherein each integrated antenna circuits includes a corresponding subset of antennas from the plurality of antennas, and wherein each integrated antenna circuit includes a pulse shaping circuit having a plurality of selectable delay paths, each pulse shaping circuit being configured to rectify and level shift a version of the globally synchronized signal through selected ones of the selectable delay paths

Abstract: An ultra-wideband clear channel assessment system uses a double-window energy technique for energy detection, which indicates a clear or busy channel.

Abstract: A wireless network device comprises a first wireless communication device that includes a first radio frequency (RF) transceiver that generates a synchronization pulse and that transmits and receives data according to a first period. A second wireless communication device receives a signal indicative of the synchronization pulse and includes a second RF transceiver that transmits and receives data according to a second period. The second period is not equal to the first period and the second wireless communication device adjusts the second period according to the first period and the synchronization pulse.

Abstract: The present invention provides a novel technique for reducing the effect of CMI for PPM UWB signals. The system and method in accordance with the present invention greatly improves the performance of receivers and eliminates the possibility of catastrophic errors. The proposed technique introduces a variable modulation index instead of a fixed modulation index as was previously known in the art. The modulation index is changed over each frame within each symbol. In other words, a time hopping modulation index sequence is used over the frames of the UWB symbols in accordance with the present invention.

Abstract: A method is disclosed for tuning each channel of a high-speed SerDes cable link interface arranged in a configuration linking a local side physical layer to a remote side physical layer. The method includes initiating an operational state of high-speed SerDes cable link interface, identifying flow-control packet Op codes not cited for use by operational high-speed SerDes cable link interface, transmitting a flow control signal from the local side physical layer to the remote side physical layer to control the remote side physical layer to monitor the bit error rate (BER) of the channels used by the local side physical layer to transfer data to the remote side physical layer, monitoring the BER in the channels used for data transfer, transferring BER data acquired in the monitoring to the local side physical layer and processing the BER data by the local side physical layer to generate equalization setting adjustments.

Abstract: Various embodiments are described for adaptive puncturing techniques involving an adaptive bit loading block to select a modulation scheme and a puncturing pattern for each of a plurality of subcarriers or subcarrier bands based on subcarrier channel state information.

Abstract: A method and system are disclosed where transmitted radar pulses are utilized for both a radar sensing function and for data communications. The data communications are performed in a manner that is simultaneous and transparent to the radar sensing function, in terms of non interference or interruption. The method and system are applicable to data communications between multiple pulsed radar devices as well as radar devices that are capable of receiving pulsed transmissions and transmitting continuous wave transmissions.

Abstract: This permits the transmission of signals over the electricity network in such a way that the spectral density of power is adjusted to the regulations in the current rules by means of the possibility of introducing notches in transmission in an efficient manner. It is characterised by the adjustment of the power in one or more carriers of an OFDM signal for generating these notches, through the use of IDFTs of at least 1024 points (if the IDFT is complex) or at least 2048 points (if the IDFT is real) and through the use of a window to multiply the symbols to be transmitted in time.

Abstract: There is provided a digital communication device for performing data communication by selecting an appropriate modulation encoding method. Quality measurement means measures the line quality of data communication from a reception signal. Adaptive modulation control means compares the line quality measured by the quality measurement means to a threshold value obtained from the interrelationship between the line quality in a plurality of modulation encoding methods and the through-put characteristic, thereby selecting one of the modulation encoding methods. Here, the adaptive modulation control means uses as the threshold value a value of the line quality at the intersection of two curves indicating the aforementioned characteristic under a condition having no disturbance among the plurality of modulation encoding methods.

Abstract: The invention relates to a method and to a modulator for modulating signals. The signals are to be transmitted by a device in packets via an air interface. Each packet is supposed to comprise at least one entity of at least two different entities, which different entities are employed for transmitting signals representing different kinds of information. In order to enable a higher data rate, signals that are to be transmitted in at least one of said different entities are modulated with a first set of values of at least one modulation parameter of a selected modulation scheme. Further, signals that are to be transmitted in at least one other of said different entities are modulated with a second set of values of said at least one modulation parameter, said second set of values comprising less values than said first set of values.

Abstract: A demodulated signal is to be generated by use of a first detection signal detected a presence/absence of a signal according to a correlation between a reception signal PPM-modulated at a pulse interval of T and a pulse variation width of ? and the reception signal delayed with a time (T+?), a second detection signal detected a presence/absence of a signal according to a correlation between the reception signal and the reception signal delayed with a time (T), and a third detection signal detected a presence/absence of a signal according to a correlation between the reception signal and the reception signal delayed with a time (T??). By thus combining a plurality of delayed detections, it is possible to obtain a UWB demodulating apparatus configured with a circuit suited for integrated circuit fabrication.

Abstract: The extended range of optical data communication is enabled through the use of intermediary relay stations spaced fairly far apart. IRDA communicatiOn, as is well known, uses very short duration optical pulses to send data up to 1 Mbit/sec; this has the concomitant effect of minimizing LED duty cycle and preventing excessive heating. The invention uses a number of integrated pulses to represent a single bit instead of utilizing a one-to-one correspondence between pulses and bits. Processing software causes the transmitter to “stutter” or repetitively emanate the identical pulse representing a bit of information. Sufficient photons are thereby gathered at a receiver to reach a predetermined threshold. A tradeoff of the data transmission frequency in this invention is that as signal intensity drops by a factor of 100 when distance increases by a factor of 10 yielding a distance/intensity ratio of 1/10.

Abstract: In a data communication system, the function of automatic repeat request is provided for transmission of packets based on a data communication protocol such as the Real-Time Transport Protocol or the User Datagram Protocol. Lost packets are detected at various timings, for example, when the beginning packet of each frame is received, the final frame of each frame is received, at a time limit of processing, and at a regular interval, and retransmission requests are issued accordingly. A data reception terminal does not issue a retransmission request if associated retransmission data will not be in time for playing with consideration of processing time and roundtrip time, thereby avoiding the transmission of useless retransmission request packets and retransmission packets.

Abstract: A method for reducing the peak-to-average ratio in an OFDM communication signal is provided. The method includes defining a constellation having a plurality of symbols, defining a symbol duration for the OFDM communication signal, and defining a plurality of time instants in the symbol duration. A plurality of tones are allocated to a particular communication device, and a discrete signal is constructed in the time domain by mapping symbols from the constellation to the time instants. A continuous signal is generated by applying an interpolation function to the discrete signal such that the continuous signal only includes sinusoids having frequencies which are equal to the allocated tones.

Abstract: The present invention concerns a system for transmitting internal messages in a synchronizing local network. The system comprises multiple computer units for running application processes. The system further comprises multiple interface units, each for transmitting an internal message from a sending computer unit to several receiving computer units. According to the invention, the system further comprises multiple external links, each for linking a computer unit to an interface unit. The system further comprises an interconnecting device for receiving messages from sending computer units and forwarding them to receiving computer units one sent message at a time.

Abstract: A receiver correlator structure for an ultra wide bandwidth communication system includes an antenna, a mixer, a bandpass filter, and a convertor. The receiver receives, via the antenna, an ultra wide bandwidth signal comprising a sequence of wavelets of particular shapes and positions, and transmits the received ultra wide bandwidth signal to the mixer. The mixer also receives and mixes with the received ultra wide bandwidth signal a local ultra wide bandwidth signal comprising a sequence of wavelets of particular shapes and positions correlated to the received ultra wide bandwidth signal. The bandpass filter removes the DC components from the mixed signal, and provides the resultant signal to the convertor. The receiver structure eliminates the local ultra wide bandwidth signal AC bias and DC bias terms and 1/f noise, yet detects long sequences of logical 1's and 0's, and allows operation with reduced bandwidth convertors.

Abstract: An ultra wide bandwidth, high speed, spread spectrum communications system uses short wavelets of electromagnetic energy to transmit information through objects such as walls or earth. The communication system uses baseband codes formed from time shifted and inverted wavelets to encode data on a RF signal. Typical wavelet pulse durations are on the order of 100 to 1000 picoseconds with a bandwidth of approximately 8 GHz to 1 GHz, respectively. The combination of short duration wavelets and encoding techniques are used to spread the signal energy over an ultra wide frequency band such that the energy is not concentrated in any particular narrow band (e.g. VHF: 30-300 MHz or UHF: 300-1000 MHz) and is not detected by conventional narrow band receivers so it does not interfere with those communication systems.

Abstract: This invention extends the range of optical data of mobile device by trading speed for distance as well as integrating a plurality of pulses over time to define a single bit of information. The present invention uses a number of integrated pulses to represent a single bit instead of utilizing a one to one correspondence between pulses and bits. The present invention executes a range extender application which executes on the mobile device without any hardware modification to the mobile device. The range extender application causes the optical transmitter to “stutter” or repetitively emanate the identical pulse representing a bit of information. Sufficient photons are thereby gathered at a receiver to reach a predetermined threshold. A tradeoff of the data transmission frequency in this invention is that a signal intensity drops by a factor of 100 when distance increases by a factor of 10 yielding a distance/intensity ratio of {fraction (1/10)}.

Abstract: An ultra wide bandwidth, high speed, spread spectrum communications system uses short wavelets of electromagnetic energy to transmit information through objects such as walls or earth. The communication system uses baseband codes formed from time shifted and inverted wavelets to encode data on a RF signal. Typical wavelet pulse durations are on the order of 100 to 1000 picoseconds with a bandwidth of approximately 8 GHz to 1 GHz, respectively. The combination of short duration wavelets and encoding techniques are used to spread the signal energy over an ultra wide frequency band such that the energy is not concentrated in any particular narrow band (e.g. VHF: 30-300 MHz or UHF: 300-1000 MHz) and is not detected by conventional narrow band receivers so it does not interfere with those communication systems.

Abstract: The invention concerns a method for connecting a device to a wireless network.

Abstract: Apparatus for driving an optical system modulator to modulate data signals onto a light wave of the optical system. The modulator driver apparatus has a limited amplifier for receiving multiplexed low speed binary data signals and for generating amplified and limited frequency output signals representative of the received multiplexed binary data signals. A differential amplifier connected to an output of the limited amplifier precisely controls the amplitude and generates a low level of over and undershoot of output signals over a wide range of the limited amplifier output signals and has an output connected to central processor unit controlled linear amplifier means for generating gain controlled high fidelity output signals characterized with low over and undershoot and a high extinction ratio for driving the modulator.