Abstract: The present invention pertains to an injection laser which advantageously suppresses mode-partition-noise. The laser comprises a laser cavity with a gain or active material and means for providing a small amplitude wavelength selective loss. In one embodiment of the present invention the means for providing a small amplitude loss is a wavelength selective reflector.

Abstract: A plurality of various rate digital subchannels are multiplexed onto a fixed rate channel by arranging the data bits from the subchannels into a framing structure consisting of j sets of i-tuples for ij bits per frame where the parameters i and j are mathematically determined as a junction of the rates of the subchannels and the rate of the fixed channel. Framing is maintained by setting each bit in the first i-tuple to ZERO and the last bit in each other i-tuple to ONE. A multiplexer-demultiplexer is described which is adaptive to the rates of the subchannels and the fixed channel in this frame structure and which can therefore be employed for any mix of subchannel and fixed channel rates.

Abstract: The present invention pertains to an injection laser which advantageously suppresses mode-partition-noise. The laser comprises a laser cavity with a gain or active material and means for providing a small amplitude wavelength selective loss. In one embodiment of the present invention the means for providing a small amplitude loss is a wavelength selective reflector.

Abstract: The present invention pertains to an injection laser which advantageously reduces main mode output power fluctuation. The laser comprises a laser cavity having an active material joined at one end to a passive waveguide. The passive waveguide has a length which is equal to or greater than the length of the active material and an index of refraction which is substantially equal to that of the active material to prevent multicavity interference. In preferred embodiments of the present invention, the passive material is fabricated from a semiconductor material having a bandgap which is larger in energy than the energy of a photon in the laser radiation.

Abstract: In order to multiplex a plurality of various rate subchannels onto a fixed rate channel, a frame structure is defined consisting of j sets of i-tuples for a total of ij bits per frame, the parameters i and j being mathematically determined as a function of the rate of the subchannels and the rate of the fixed channel. For j-l of the i-tuples, i-l bits are used for information and the last bit is set ONE. In one i-tuple all i bits are set ZERO. Framing is detected by monitoring for a ONE followed by i ZEROes, a pattern which cannot occur elsewhere in the frame regardless of the data. An integral number of information bits from each subchannel are distributed in the (i-l)(j-l) information bit positions. In the disclosed embodiment two 6662/3 bps channels and a 4800 bps channel are multiplexed onto an 8000 bps channel using a frame structure consisting of 24 quintets. In the 92 information bit positions, 72 bits are allocated for the 4800 bps channel and 10 bits each are allocated for the 6662/3 bps channels.

Abstract: In the transmission of PCM coded picture elements (pels), the level value of each pel of an image is quantized in accordance with one-of-a-plurality of quantization schemes that is determined by the quantized level values of adjacent neighbor pels. Each of the quantization schemes is configured from the relative frequency of occurrence of each pel level value for a given combination of neighbor pel level values. Various embodiments may involve grey-level values of each pel of an image, the three-dimensional red, green and blue level values of an image quantized in accordance with a three-dimension quantization scheme determined by the three-dimensional quantized level values of adjacent neighbor pels, or three-dimensional color values that a prequantizer quantizes and linearizes into one-dimension that are then conditionally quantized using one-dimensional grey-level techniques.

Abstract: A guy hook used to attach a guy cable to a transmission line pole includes an upper body portion (25), a central body portion (26), and a lower heel portion (27). The upper portion has a neck (29) and ears (28) for engaging the guy cable. The central body portion has a rearward pole-engaging surface (37), an opposite frontward side and a passageway (40) therebetween through which a through-bolt is horizontally disposed to install the hook on the pole. The frontward side includes a recess (38) surrounding the aperture (39) to the passageway for countersinking the head of a through-bolt below the frontward side to a depth substantially in line with the vertical line of action (41-42) of the hook. The moment caused by the downward and outward force exerted on the hook by the guy cable is thus minimized and therefore also the tendency of the hook to overturn and bend the through-bolt.

Abstract: A buffer arrangement on an integrated circuit is disclosed which translates the voltage levels of logic signals without distortion. Generally, signal distortion results from the difference between the low-to-high propagation delay and the high-to-low propagation delay through an individual buffer. The arrangement includes two buffers (33, 36) having unknown distorting characteristics, arranged in series-inverting pairs (31, 33; 35, 36). The first buffer (33) generates a predistorted signal from the signal to be translated, which has a delay at each transition due to either the high-to-low or low-to-high propagation delay of that buffer. By inverting (35) and redistorting the predistorted signal through a second buffer (36), each transition in the signal at the output thereof is further delayed due to a propagation delay opposite in type to that which that same transition was delayed by the first buffer.

Abstract: A high-speed, high pin-out chip carrier package (10) for interconnecting at least one LSI or VLSI chip to a circuit pack is disclosed. The package includes a ground plane (19), a power plane (20), and at least one signal layer (15, 16, 17, 18) containing plural conductors therethrough. Layers (85) of dielectric material separate adjacent conductive layers, (15, 16, 17, 18, 19, 20). By controlling, in design, the width of each signal conductor and its distance to the nearest ground (19) or power plane (20), the package is impedance-matched to the circuit pack. Plural plated-through holes (21) are disposed through the package for electrically interconnecting the signal conductors, the ground plane (19), and the power plane (20) to the circuit pack, and are arranged in a pattern to reduce inductive noise.

Abstract: Heat generated from electronic equipment packed densely on a circuit board is transferred to conductive partition plates located adjacent to and on opposite sides of the circuit board. Heat is then transferred from the partition plates to conductive shelves located above and below the partition plates and then to a conductive rear wall of a cabinet. Heat is then transferred through the rear wall to a plurality of external fins and then to the atmosphere by radiation and convection. Alternatively, the circuit boards are housed in sealed enclosures. A clamp, fastened to the rear wall of the cabinet, is used for securing the sealed enclosure and for transferring the heat from the electronic equipment to the rear wall.

Abstract: The wave digital filter derived from a symmetric lattice reference filter includes two one-port networks each of which consists of storage elements interconnected by arithmetic units. Each arithmetic unit comprises a digital multiplier and three digital adders. Higher order filters thus require a substantial amount of arithmetic hardware. In accordance with the present invention, the amount of arithmetic hardware in the wave digital filter derived from a symmetric lattice filter is substantially reduced by multiplexing an arithmetic unit in each one-port network. In particular, a single arithmetic unit in each one-port is successively configured as each individual arithmetic unit of the non-multiplexed one-port. Intermediate output signals are stored in temporarily vacant storage elements. In one described embodiment of the present invention, the two multiplexed one-port networks of the wave digital filter are further multiplexed to require only one arithmetic unit.

Abstract: A repeatered submarine cable has a composite inner conductor for accommodating a system of optical fibers therein. The cable strength members include a central elongated filament and plural layers of stranded steel wires separated from the central filament by an annular insulating core member, in which the optical fibers are embedded. A metallic tubular jacket surrounds the stranded steel layers to provide both a DC path for powering the optical repeaters and a hermetic moisture barrier for the fibers.

Abstract: In a multibeam digital time-division switched satellite communications system users of differing capacity needs are efficiently served by quantizing the capacity of each ground station and similarly the bit repetition rate of each ground station into integral powers of 2. At the satellite the uplink bitstream transmitted by each ground station is recovered and the higher rate bitstreams are demultiplexed to form plural equal bit rate subchannels at the input to the satellite switch, the number of subchannels formed being equal to the quantized capacity of the associated ground station. After the satellite switch transfers the bits present at the switch inputs from all ground stations to the appropriate switch outputs, a plurality of output subchannels are multiplexed to form the higher bit rate signals, the number of subchannels multiplexed being equal to the quantized capacity of the ground station to which the bits are directed.

Abstract: A terminating portion of an optical fiber waveguide having a polished beveled end is laterally disposed directly on the light-emitting surface of a light-emitting diode (LED). The light power coupled into the fiber consists of two components: the light power directly coupled into the fiber all along the region of contact between the fiber and the light-emitting surface; and the light power reflected by the beveled end and directed along the fiber axis.

Abstract: A waveguide bandstop filter is described. Two ceramic dielectric disc resonators each having a resonant frequency f.sub.0 and separated by 3/4.lambda.go, where .lambda.go is the wavelength at f.sub.0, are each disposed in individual apertures in the waveguide wall. The substantial portion of each resonator is exterior to the waveguide cavity and surrounded by a metallic housing which isolates each resonator from each other. The resonators are oriented so that a coupling arrangement exists between the electromagnetic energy propagating through the waveguide and each resonator so that a resonant mode is excited therein at frequency f.sub.0.

Abstract: The concentricity or eccentricity of a plastic coating on an optical fiber is determined by monitoring the absence or presence, respectively, of a particular intensity peak in the backscattered light pattern generated by a light beam incident upon the fiber as the fiber is drawn, coated and pulled through the light beam. The particular intensity peak monitored results from the rays of minimum deviation which traverse the optical fiber only once as the incident rays are refracted and reflected through the coated fiber to form the backscattered light pattern. The position of the coating applicator is automatically adjusted if this intensity peak is electronically detected.

Abstract: The operating current level of an injection laser is stabilized at a point of maximum linearity. A test signal modulates the laser current, and the operating current level of the laser is automatically adjusted until the harmonic distortion component in the output light at twice the test signal frequency is minimized.

Abstract: An injection laser is automatically stabilized so that the laser operates above threshold when the laser current is modulated. The invention makes use of the fact that the laser junction voltage saturates at currents above the threshold. A signal which modulates the laser current and causes the laser current to fall below the threshold level therefore results in a change in the junction voltage. These changes in the junction voltage are monitored and used to increase the bias current so that the laser operates above threshold.

Abstract: It has been determined that unique discharge signature waveform shapes are associated with the corona discharges in the components of the power separation filters of repeaters and equalizers. These signature waveform shapes, present across the repeater or equalizer terminals, can be measured and identified by artificially contaminating and inducing corona discharges in the high voltage components. A discharge signal subsequently generated in response to a corona discharge across a high voltage component of a repeater or equalizer of a similar type will have the same shape as one of the signature waveforms. Thus, a corona discharge from a repeater or equalizer under test can be located by comparing its discharge signal with the catalog of signature waveforms.

Abstract: Dispersion is reduced in a graded index optical fiber having a finite number of core layers by introducing slow longitudinal variations into the thickness of each layer. The thickness of each layer varies between maxima and minima, the latter being proximate to zero.