Abstract: The invention relates to an optical receiving station, an optical communication system, and a dispersion controlling method for precisely controlling chromatic dispersion in an optical transmission line or chromatic dispersion in an optical transmission line that varies with time. An optical receiving station is provided with a dispersion compensating section for receiving, via an optical transmission line, an optical signal modulated according to an optical duo-binary modulation method and for changing a dispersion value to be used for compensating for chromatic dispersion in an optical transmission line, an intensity detecting section for detecting the intensity of a specific frequency component of the optical signal output from the dispersion compensating section, and a controlling section for adjusting the dispersion value of the dispersion compensating section so that the output of the intensity detecting section has a predetermined extreme value.

Abstract: The present invention provides an optical receiver that uses an avalanche photodiode (APD) whose multiplication factor m is controlled to compensate the temperature dependence thereof. An optical module of the present invention includes a light-receiving device in addition to the APD. The light-receiving device may be a semiconductor thin film or a PIN photodiode, and is disposed in front of the APD. Accordingly, the light-receiving device receives a portion of signal light, and transmits a rest portion thereof. The APD receives the rest portion of the signal light. The bias voltage applied to the APD is so controlled that a first photocurrent generated in the light-receiving device and a second photocurrent generated in the APD maintain a constant ratio.

Abstract: A light concentrator for an optical antenna gradually narrows from the light receiving end to the end in contact with a light detector, and has a refractive index that gradually increases from the first to the second end, to afford a greater acceptance angle for the incoming optical signal. The increase may occur in stages of corresponding layers of the light concentrator, the layers being arranged in order of increase in refractive index from the first end to the second end.

Abstract: Multiple electrical signals (from, for example, multiple signal sources such as antennas) are converted by an electrical signal input (24) into corresponding optical signals. In one embodiment these electrical signals are comprised of temporally separated data elements. In this case, in a preferred embodiment, the optical signals mirror these temporal conditions. In addition, in a preferred approach, the optical signals are physically grouped such that temporally coincident data elements from each of the multiple electrical signals are positioned proximal to one another. The resultant optical signals are then correlated, in parallel, with a correlation reference (26) by an optical correlator lens (25). In one embodiment, the optical signals are subjected to a Fourier transformation (31) and distorted (32) as necessary to normalize these resultant optical signals with the correlation reference (26). The optical correlation then occurs in the Fourier domain.

Abstract: An optical receiver includes a PIN photodiode (PIN-PD) having an incident surface for receiving signal light, the PIN-PD transmitting a part of the signal light to the surface opposite to the incident surface, and an avalanche photodiode (APD) having an incident surface for receiving light transmitted through the PIN-PD. In the optical receiver, the ratio of the quantity of signal light detected by the PIN-PD and the ratio of the quantity of signal light detected by the APD are not affected by the polarization state of the signal light incident on the optical receiver, and accordingly the avalanche multiplication factor of the APD is suitably controlled on the basis of the signal light detected by the PIN-PD.

Abstract: A light receiving apparatus comprises a holographic optical device having a plurality of holograms recorded in a light receiving surface thereof. The holographic optical device is configured to diffract light of a predetermined wavelength incident thereon from different directions onto a common focal area. The holographic optical device is shaped such that a first vector normal to the light receiving surface at a first location thereon is oriented along a first direction and such that a second vector normal to the light receiving surface at a second location thereon is oriented along a second direction, the second direction being different from the first direction.

Abstract: An optical receiver for enhanced optical power sensitivity for optical signal at 10 Gbps includes an optical package and a supporting electrical circuitry. The optical package includes a semiconductor optical amplifier to pre-amplify the incoming weak signal, a tunable optical filter to suppress the spontaneous noise of the amplifier and a PIN diode as an optical detector. A supporting electrical circuitry includes a control loop for the filter to track the peak of the optical signal. By optimizing the parameters of all the elements, the final sensitivity of the optical receiver can be increased significantly. The device may be realized in a single package.

Abstract: A receiver and method for using the same to process optical signals is disclosed. The receiver includes an optical coupler and a polarization dependent beam splitter. The optical coupler combines an input signal and a local oscillator signal into a first combined signal. The optical coupler includes a polarization filter that operates on the local oscillator to provide a linearly polarized signal having a predetermined LO polarization direction.

Abstract: Methods and apparatus for monitoring the power level of one or more optical emitters are provided. In some embodiments, optical signals from two or more optical emitters are directed at different regions of a photo detector. The photo detector may include two or more spaced contacts that are adapted to receive different contributions of photo current from each of the optical signals. By monitoring the photo currents in the two or more spaced contacts, a measure of the optical power of each of the optical signals may be determined.

Abstract: Use in an optical communications system of multiple detectors to separately detect respective multiple spectral modes of a received optical signal. The invention also provides for corresponding multi-channel, dispersion-tolerant optical receivers. Embodiments are presented both for direct detection and for coherent detection of optical signals.

Abstract: A receiver for an optics telecommunication system, the receiver comprises a first receiving device and means for focusing a received light beam carrying a signal towards such first receiving device. The receiver is characterized in that it further comprises at least a second receiving device and a beam splitter for splitting the focused light beam partially towards the first receiving device and partially towards the at least second receiving device. Tipically, the first receiver device is an APD diode while the second receiver device is a PIN diode. The telecommunication system is a Free Space Optics telecommunication system. A method is also described. The invention results in a high dynamic receiver. The dynamic of the invention receiver could be up to the sum of the dynamics of receivers provided with single receiving device (APD or PIN).

Abstract: The present invention relates to a device for detecting or generating and modulating optical signals, and having an angular dispersive element arranged to change angles of the optical signals or carrier and/or reference rays brought to interference.

Abstract: A device and a method for detecting received optical power in an optical communication network, the device mainly including: an optical splitter for separating a part from an uplink optical signal received by an optical receiver in the optical communication network and transferring the part of optical signal to a photoelectric converter; the photoelectric converter for converting the received optical signal transferred from the optical splitter into a current or voltage signal and transferring the current or voltage signal to a logic control circuit; and the logic control circuit for judging the received current or voltage signal transferred from the photoelectric converter according to a set threshold to determine whether the received optical power of the optical receiver in the optical communication network overloads, and for outputting a corresponding control signal.

Abstract: Method and apparatus for reducing intra-channel distortions of received data resulting from non-linear signal propagation includes parallel detection subcircuits for determining output values of sequentially provided optical data bits such that each of the sequentially provided optical data bits is processed by only one of the parallel detection subcircuits. Two parallel detection subcircuits process the input optical data bits according to even valued and odd valued clock signals. Each subcircuit has first and second signal analyzers to detect the value of the input optical data bit and a first memory unit and a second memory unit connected to the first and second signal analyzers. The input value of clock information provided to the first and second memory units of the first parallel subcircuit are 180° out of phase with input values indicative of a clock speed provided to the second parallel subcircuit.

Abstract: Optical receiver modules are used for receiving high-speed optical data signals. Unfortunately, these optical receiver modules are often tested for the first time after they are packaged in a housing. Thus significant costs are associated with those packaged devices that fail to meet predetermined criteria. An integrated optical receiver module is proposed that has an optical detector direct attached, or flip-chipped or bumped, onto an integrated circuit having an amplifier circuit. The direct attach process is performed when the integrated circuits still reside on a semiconductor wafer prior to dicing thereof. Thus, high speed optical testing of the optical receiver module is possible on a wafer level to determine actual performance characteristics thereof prior to dicing.

Abstract: An optical transceiver is provided that includes a transceiver substrate arranged substantially perpendicular to longitudinal axes respectively defined by a transmit optical subassembly and receive optical subassembly. The transceiver substrate is configured to electrically and physically connect to the transmit optical subassembly and the receive optical subassembly, and includes a connector configured and arranged to interface with a host bus adapter. The combination of the host bus adapter and optical transceiver is sized and configured to be received within a standard slot of a host system, such as a PCI or PCMCIA slot. In this way, one or more optical connections are integrated within the host device or system.

Abstract: An optical signal receiver including a plurality of threshold decision circuits configured to receive an electrical signal representative of the optical signal. Each of the threshold decision circuits is configured to sample the electrical signal and to provide an associated threshold decision circuit output in response to a comparison of the signal to an associated threshold level. The threshold decision circuit outputs are coupled to an output decision circuit, which is configured to output a signal representative of a binary state of the optical signal. An optical communication system and a method of reconstructing received data signal in an optical communication system are also provided.

Abstract: A polarization diversity receiver has an optical section for converting the received optical signal into four or five polarization diverse component optical signals that substantially represent amplitude and polarization state information of the received optical signal, by respective polarization transformations to respective points on a Poincaré sphere, the points being equally spaced apart to maximize polarization diversity, even in the worst case input polarization state. Detectors produce component electrical signals from each of the component optical signals, for electronic processing to compensate for PMD. By reducing the number of component optical signals significant cost and size reductions are enabled. The need for precise polarization tracking in the receiver can be reduced or eliminated completely. Balanced detectors can be used to reduce the number of electrical signals. The electrical processing can use sequence detection.

Abstract: An optical communication system configured to operate with optical signals at lower signal to noise ratios than previously contemplated. The communication system includes a receiver having an optical pre-processor coupled between a demultiplexer and a detector. The optical pre-processor includes either an optical polarization section having a polarization rotator and an optical polarizer, a phase modulation section that includes a phase modulator and a dispersion element and a clock recovery circuit, or an amplitude modulation section that includes an amplitude modulator clock recovery circuit and a spectral shaping filter.

Abstract: A method and system for transmitting information in a wavelength division multiplex (WDM) or other suitable multichannel optical communication system includes receiving a multichannel signal having a symbol rate and comprising a plurality of non-intensity modulated optical information signals. The non-intensity modulated optical information signals have a minimum channel spacing comprising a multiple of the symbol rate within 0.4 to 0.6 of an integer. The non-intensity modulated optical information signals are separated from the multichannel signal and each converted into an intensity modulated optical information signal using an asymmetric interferometer. A data signal is recovered from the intensity modulated optical information signal.

Abstract: A differential quadrature phase shift keyed system includes a fiber optic source and a first fiber optic differential phase shift keyed demodulator coupled to the fiber optic source having a first phase differential. A second fiber optic differential phase shift keyed demodulator is coupled to the fiber optic source disposed parallel with the first fiber optic differential phase shift key demodulator. The second demodulator has a second phase shift differential equal to the first phase differential plus about 90 degrees.

Abstract: High bandwidth angle modulated communications may be obtained using an incoherent/broadband “white light” source. The light is passed through interferometer arms before and after a communication link. The light is modulated in a transmitter signal optical angle modulator and in a reference optical angle modulator. By locating an interferometer and light source at a receiver, the light passes through the interferometer both before and after the optical link to the transmitter. A balanced detector implements subtraction of non-interfering light.

Abstract: The present invention is directed to a laser communication receiver for wireless optical communication. A laser communication receiver includes a diffractive optical element to permit detectors at different spatial locations to detect different wavelengths of the optical signal. An immersion lens may be employed to focus the optical signal to a spot size smaller than the photoactive area of the detector. In one detector configuration, the optical signal is folded by a reflective surface and focused on a plurality of stacked detectors. The present invention further provides a method of manufacturing a detector and immersion lens assembly that provides a high degree of alignment between the lens and the corresponding detector.

Abstract: An optical data receiver for the distribution and demodulation of compressed TDM data packages comprises, optical distributor means to which the data packages are applied for selective distribution to a plurality of AWG optical demultiplexer/detector arrays, so that each demultiplexer/detector array provides in respect of each data package fed thereto from the optical distributor, a data word the bits of which are presented in parallel.

Abstract: An optical performance monitor particularly well-suited for use in dense wavelength-division multiplexed (DWDM) systems includes both a nonlinear optical detector and a conventional linear detector. The nonlinear optical detector, which may comprise a quadratic detector, is used to provide information, on a channel-by-channel basis, regarding chromatic dispersion, polarization mode dispersion and accumulated amplified spontaneous emission (ASE) noise in each signal wavelength.

Abstract: An optical vestigial sideband transmitter includes first and second intensity-modulated light sources and a pair of optical splitters. A first and second wavelength combiner receives a portion of the outputs of the first and second intensity-modulated light sources. The first wavelength combiner filters the two modulated signals to generate two vestigial sideband signals and multiplexes them onto a single waveguide such as an optical fiber for output to an optical transmission medium. The second wavelength combiner operates in conjunction with the first wavelength combiner to automatically and precisely regulate the optical wavelengths of the light sources, such that the passband of the first wavelength combiner substantially suppresses the redundant sideband from each modulated signal. After transmission, a vestigial sideband receiver including a wavelength splitter and optical-to-electrical receivers extracts the multiplicity of vestigial sideband signals placing them on separate optical waveguides.

Abstract: To provide a light-receiving element that is capable of high-speed operation and includes an optical element with controlled setting position, shape and size, a manufacturing method for the light-receiving element, and an optical module and an optical transmitting device including the light-receiving element, a light-receiving element includes a base member provided over a light-receiving surface, and an optical element provided on a top surface of the base member.

Abstract: The present invention provides an optical system for decoding, switching, demultiplexing, and routing of optical encoded data symbols, including: a plurality of optical paths having first and second terminals; a splitting mechanism for directing the encoded data symbols to each of the first terminals; a plurality of decoding devices for producing decoded signals in response to the encoded data symbols; and each of the optical paths includes, between the first and second terminals, at least one of the decoding devices to produce one of the decoded signals at one of the second terminals in response to one of the encoded data symbols.

Abstract: The output monitor/control device is provided with: Mach-Zehnder circuit 104 that receives a light beam, branches the light beam into two light beams having a phase difference of 180°, and transmits each of the light beams, exhibiting a periodic optical transmittance-optical frequency characteristic a period of a frequency interval corresponding to a predetermined free spectral range; first and second photodiodes that each receive one of two light beams supplied from the Mach-Zehnder circuit; calculation circuit 108 that calculates a predefined discrimination formula for evaluating wavelength change of the light beam based on output currents of the photodiodes; and wavelength control circuit 111 that detects change in wavelength based on the calculation results by the calculation circuit and adjusts the wavelength to a set value.

Abstract: An optical receiver, small and inexpensive, is used for a WDM transmission system in place of a wavelength demultiplexer. In the receiver, a light-transmitting medium and a photodiode (PD) are placed on the same substrate, a wavelength-selecting filter is attached perpendicularly or obliquely to the end face of or to a cut section at the midpoint of the medium, the filter transmits only the assigned wavelength included in the incident light having multiplexed wavelengths, and the PD detects only the assigned wavelength. With an optical fiber, the fiber can be housed in a ferrule. In this case, the filter is inserted into a filter-supporting hole provided at a midpoint of the ferrule, the ferrule is fixed in a groove formed on the substrate, and an optical pathway-changing groove formed on the substrate reflects light having emerged from the optical fiber to introduce it into the PD.

Abstract: Accordingly, an aspect of the present invention provides a method of dynamically controlling a bias point of a photodiode of an optical receiver. According to the present invention a performance parameter indicative of an eye opening of an optical signal received by the optical receiver is detected. A bias voltage of the photodiode s dynamically adjusted so as to optimize a value of the detected performance parameter.

Abstract: An optical receiver module is disclosed with a top open can (TO-Can) structure that includes a stem with holes thereon. The holes pass through both sides of the stem. A photo diode mounted on an upper side of the stem, for converting an optical input signal into an electric current. The optical receiver module includes a trans-impedance amplifier, mounted on the upper side of the stem, converts the electric current output from the photo diode into RF signals having opposite phases, amplifies the converted RF signals, and outputs the amplified RF signals to the outside via corresponding output terminals. Signal leads, passing through the holes formed on the stem, output the RF signals having the opposite phases amplified by the trans-impedance amplifier to the outside. Ground leads, extending from a lower part of the stem, ground the stem to the outside of the optical receiver module.

Abstract: An air temperature control assembly has an air temperature control unit with an optical receiver. A cover houses the air temperature control unit and the optical receiver. A light guide reflects light signals to the optical receiver. The light guide may be a reflecting surface angled to direct the light signal to the optical receiver.

Abstract: A communication system including an infrared receiver that receives optical infrared signals. The infrared receiver utilizes an array of photo-sensors for detecting optical infrared signals within a solid angle. Each photo-sensor, however, detects optical infrared signals in only a predetermined portion of the solid angle. On detecting optical infrared signals, each photo-sensor converts and forwards a corresponding electrical signal to a filter circuit that selectively determines whether the signal meets a predetermined criteria such as a frequency threshold. The filter circuit or other processing circuitry is thereby able to identify photo-sensor(s) providing an optimal infrared communication link. The infrared receiver may include an optical system comprising a lens assembly that directs the optical infrared signals towards the array of photo-sensors.

Abstract: Apparatus and method is described for using a silicon photon-counting avalanche photodiode (APD) to detect at least two-photon absorption (TPA) of an optical signal, the optical signal having a wavelength range extending from 1.2 ?m to an upper wavelength region that increases as the number of photons simultaneously absorbed by the APD increases beyond two. In one embodiment, the TPA count is used by a signal compensation apparatus to reduce dispersion of a received optical pulse communication signal subjected to group velocity dispersion, polarization mode dispersion, or other signal impairment phenomena which effect the TPA count. Another embodiment, the TPA count is used to determine the optical signal-to-noise ratio of a received optical pulse communication signal. Another embodiment uses the TPA count to determine the autocorrelation between a first and second optical pulse signals as a function of the relative delay between the first and second optical pulse signals.

Abstract: A device including an input port configured to receive an input signal is described. The device also includes an output port and a structure, which structure includes a tunneling junction connected with the input port and the output port. The tunneling junction is configured in a way (i) which provides electrons in a particular energy state within the structure, (ii) which produces surface plasmons in response to the input signal, (iii) which causes the structure to act as a waveguide for directing at least a portion of the surface plasmons along a predetermined path toward the output port such that the surface plasmons so directed interact with the electrons in a particular way, and (iv) which produces at the output port an output signal resulting from the particular interaction between the electrons and the surface plasmons.

Abstract: The optical receiver comprises an optical input path, a light detector array, an optical converging element and an information signal generator. The light detector array includes light detectors and a light-sensitive surface. Each light detector generates an electrical signal in response to light. The optical converging element is located to focus an optical input signal received via the optical input path to form a spot on the light-sensitive surface of the light detector array. The spot has an area less than the area of the light-sensitive surface but greater than the area of one of the light detectors. The information signal generator generates an electrical information signal from at least one of the electrical signals. In an embodiment, the information signal generator includes a summer that sums the electrical signals generated by the light detectors to generate the electrical information signal.

Abstract: A radar and laser detection device for mounting upon a motorcycle is described which provides increased concealment, security, safety, ease of use and functionality specific to the needs of motorcycle drivers. A method of semi-permanently mounting the device is described which requires no permanent alterations to the vehicle while providing improved visibility of alarm signals, a simple display technique, and controls which do not require the operator to remove his/her hands from the vehicle handlebars.

Abstract: A bi-directional communication assembly is provided with commonly available optoelectronic components in a compact package. Diplex functionality is achieved by orienting the receiving detector at an angle with respect to the transmitting beam. An interference coating inside the detector, on the detector surface, or on a surface in intimate contact with the detector, reflects the transmitted beam while simultaneously allowing the receiving beam to pass through the coating to the light absorbing region. The combined function of the receiving detector, providing advantages of a common beam path and close proximity of the components, enable a compact package that can be placed within the space usually occupied by the transmitter light source alone.

Abstract: An array of diffraction grating coupled infrared photodetectors is coupled to corresponding high-speed amplifiers for creating a multiple channel high speed receiver for an optical communication system. Each photodetector includes a three-dimensional diffractive resonant optical cavity formed by a diffraction grating that resonates over a narrow range of wavelengths. By creating different resonant optical cavities, the receiver detects each optical channel individually, thereby simplifying receiver design. The receiver finds ready application in systems based upon high power CO2 lasers and semiconductor lasers such as quantum cascade lasers allowing extremely long line of sight communication, such as between satellites. Other applications include ship to ship or ground to missile communications. These applications will benefit from increased jamming resistance and security.

Abstract: An optical channelizer system that is adapted to provide instantaneous RF signal channelization at frequencies on the order of 100 GHz or more into channels having bandwidth as small as a few megahertz. In order to improve the channel resolution the optical channelizer system is formed from a plurality of parallel subchannelizers, for example, twenty-five parallel sub channelizers which can provide 1 GHz channel spacing and 40 MHz signal resolution.

Abstract: Optical signals are received from a free-space link by directing received light onto a plurality of microlenses and then directing light received through each of the microlenses into a respective single mode optical fiber (SMF). Light beams from the SMFs are combined into a single light beam in one SMF. The single light beam is amplified with a multi-wavelength fiber amplifier and attenuated with a variable optical attenuator. The power gain of the multi-wavelength fiber amplifier and the attenuation of the variable optical attenuator are controlled. The single light beam is directed into a fiber optic communication system that is optically coupled to the variable optical attenuator.

Abstract: A high speed optical receiver comprises, in combination, a non-imaging light gathering device for directing light from its entrance pupil to its exit pupil according to the edge ray principle and a photonic detector coupled to the exit pupil and having an anti-reflective micro-structured active surface area dimensioned to minimize capacitance effects commensurate with achieving a desired signaling speed.

Abstract: An optical transceiver includes an opaque element having a concave reflective surface arranged in a path of each of an outgoing and an incoming light signal, the reflective surface configured to redirect the paths of the respective light signals. An optical detector is arranged facing the reflective surface. The optical detector is configured to detect a redirected incoming light signal from the reflective surface and to generate therefrom a receive signal proportional to the incoming light signal. An emitter is arranged facing the reflective surface. The emitter is configured to generate the outgoing light signal proportional to a transmit signal. A lens assembly is arranged between the reflective surface of the opaque element and both the optical detector and the emitter. The lens assembly is configured to couple the redirected incoming light signal to the optical detector and to couple the outgoing light signal to the reflective surface.

Abstract: An optical signal alternately traverses a total of n couplers and n−1 DGD units, arranged therebetween, with a differential group delay between two signal modes. The power division between the two signal modes is measured in each DGD unit in a power division controller, and a signal that is proportional to the difference between the powers in the two signal modes is obtained. The signal is led to an integrating controller whose control signal is led to a differential phase shifter that is accommodated in the DGD unit present upstream in the beam path. The difference between the powers of the two signal modes is thereby brought to zero at least approximately. This has the consequence that it is essentially only the chromatic dispersion that is generated or equalized, but no other disturbing distortions of the optical signal are produced.

Abstract: A high speed optical receiver comprises, in combination, a non-imaging light gathering device for directing light from its entrance pupil to its exit pupil according to the edge ray principle and a photonic detector coupled to the exit pupil and having an anti-reflective micro-structured active surface area dimensioned to minimize capacitance effects commensurate with achieving a desired signaling speed.

Abstract: An optical interconnect comprises an input configured to receive light of a plurality of light wavelengths and a plurality of holographic optical elements. Each element configured to reflect one out of the plurality of light wavelengths and allowing others of the plurality of wavelengths to not be reflected. Each of a plurality of prisms is configured to rotate received light at a different angle than any of the other prisms. For each holographic optical element, one of the plurality of prisms is positioned to receive and rotate light reflected by that holographic element. Each of a plurality of beam splitters is positioned to receive light rotated by a respective one of the plurality of prisms and all the plurality of beam splitters direct light to an output of the optical interconnect.

Abstract: The invention relates to an arrangement for operating an optical transmission or reception module at high data rates of up to 10 Gbit/s, having a TO package with electrical connections, an optical transmission or reception module arranged in the TO package, and a circuit board for making electrical contact with the electrical connections of the TO package. According to the invention, the circuit board (6) has RF lines (81, 82) and the electrical connections (41, 42) are connected to the RF lines (81, 82) in an arrangement parallel to the plane of the board. Preferably, provision is also made for an RF matching circuit to be produced on the board and for SMD components to be fitted directly and without further solder pads onto planar RF lines on the RF board. The cited measures serve to improve the RF properties of a TO module.

Abstract: A receiver (EMP1, . . . , EMPn) is disclosed for receiving optical signals from an optical transmission network (NET) serving to transmit coded, multiplexed optical signals. The receiver (EMP1, . . . , EMPn) includes a means (DEK1) for detecting the optical signals to be received, e.g., a Fabry-Perot filter, and processing means (O/E1, 0/E2, 5) to compensate noise present in the detected optical signals by combining the detected optical signals with compensation signals. The means (DEK1) is adapted to transmit optical signals to be received and reflect optical signals not to be received. A further means (K1), e.g., an optical coupler, is provided for deriving the compensation signals from at least part of the reflected optical signals and then applying the compensation signals to the processing means (O/E1, O/E2, 5).

Abstract: A method and a device for receiving a broadband light pulse modified in the time and frequency domains, the light pulse comprising at least one frequency component. The method comprises receiving the light pulse at a particular moment, separating the frequency components of the light pulse from each other, converting each frequency component into an electrical pulse, performing a first comparison to compare the magnitude of each electrical pulse to a predetermined threshold value, performing a second comparison to compare said electrical pulses exceeding the threshold value at a particular moment, and deciding the bit value in response to the second comparison conducted.

Abstract: A method of consolidating a body in any of initially powdered, sintered, fibrous, sponge, or other form capable of compaction, including the steps: providing a bed of flowable particles within a contained zone, the particulate including flowable and resiliently compressible carbonaceous particles; positioning the body in the bed, to be surrounded by the particles; effecting pressurization of the bed to cause pressure transmission via the particles to said body, thereby to compact the body into desired shape, increasing its density; the particles being heated to elevated temperature prior to compacting of the body into desired shape; and the heating of the particles being effected by passing electric current through same, with heat generated in the particles also to be transferred to the body.The electrically heated mass of particles may be fluidized; the particles may consist of graphite; and the body may consist of metal, ceramic, or synthetic resin.