Abstract: A method and system for forming microlens (78) on an optical fiber (60) include optical fiber lensing device (10) having lowering mechanism (18) for inserting optical fiber (60) at a predetermined and controlled speed to a predetermined depth in oil-acid bath having oil layer (62), acid layer (64), and boundary (68) between oil layer (62) and acid layer (64). The next step is to etch optical fiber (60) at boundary (68) by forming meniscus (66) around optical fiber (60) to selectively and controllably form on optical fiber (60) a microlens (78) having a predetermined shape, preferably a hyperbolic shape. The etching includes the steps of first tapering optical fiber (60) to a shape determined by the distance that optical fiber (60) is first inserted into acid layer (64). The etch step further chemically mills microlens (78) on optical fiber (60) to the predetermined shape by controlling the etch time and position of optical fiber (60) relative to boundary (68) for etching optical fiber (60) at boundary (68).

Abstract: A method of constructing a circuit for communicating electrical signals and assembled at least in part by an automated assembly machine is disclosed. The automated assembly machine is operable to select from a plurality of components. The circuit includes a material having a first and second surface and a length. A strip conductor is positioned along the first surface of the material. A ground structure is disposed along the length of the second surface. Finally, a low impedance device selected from the plurality of components is electrically coupled to the ground structure on opposite sides of the strip conductor, wherein the coupling of the low impedance device to the ground structure forms a circumferential shield around the strip conductor. Various alternative embodiments, as well as fabrication methodology are also disclosed.

Abstract: A method and circuitry are provided for detecting and measuring a phase difference between the output signals from a primary stratum clock and a standby stratum clock in a telecommunications system, computing a period of time needed for a numerically-controlled oscillator to shift the frequency of the standby clock enough to cancel the phase difference, transforming the required period of time into a signal representing a corresponding number of frequency shift steps, and controlling the numerically-controlled oscillator with the step signal to shift the frequency of the standby clock accordingly and thereby cancel the phase difference. Both the frequency and phase alignments of the two clocks are thus maintained. Therefore, when either the system or user switches operations from the primary stratum clock module to the standby stratum clock module, phase-related transients are not generated, which results in a significant increase in the overall performance and reliability of the system.

Abstract: In an optical fiber transmission network, a remote terminal fed by a high-rate optical signal includes an internal electrical link called a serial interface bus carrying 24 DS0 channels. The optical transmission network is extended by converting the SBI baseband signal from electrical to optical and transmitting the SBI optical signal over a distribution fiber to a network unit located in the neighborhood of the subscribers.

Abstract: A circuit for recovering a clock signal from incoming data and for retiming the incoming data comprises circuitry for generating a plurality of phased clock signals responsive to a selected frequency and clock recovery circuitry for generating a recovered clock from the plurality of phased clocks and the incoming data. The recovered clock is used to retime the data, which may be either RZ or NRZ data. To recover clock from the incoming data, the presence of a logic "1" is detected in one or more data streams and the phase of the data relative to the phased clocks is determined. Hold circuitry stores the phase information during the interval between logic "1" bits and aligns the phase information with the leading phased clock. Compare circuitry and counter circuitry detect changes in phase information to insure that a change is not merely the result of a metastable anomaly.

Abstract: A virtual tributary (VT) or tributary unit (TU) of a selected size is multiplexed with transport overhead and further multiplexed with framing bandwidth of an underlying transport technology for providing a virtual tributary/tributary unit plus transport link overhead plus transport framing for transport on a selected transport technology. This enables individual virtual tributaries/tributary units to be transported with defined line overhead and using existing transport technology framing. Several examples of underlying transport technologies used in conjunction with selected transport formats for VT-1.5 and VT-2 superframes are shown.

Abstract: In an optical fiber telecommunications network for providing both narrowband telephony signals and broadband video services over a single optical fiber using a single optical carrier, an optical distribution shelf includes a plurality of optical distribution units and interface units for interfacing with a controlling microprocessor. The optical distribution units receive baseband TDM telephony signals in serial format and the broadband video signals and function to frequency division multiplex the broadband video signals with the baseband telephony signals. The multiplexed signal is used to frequency modulate an optical carrier for transmission on a single optical fiber.

Abstract: A method and apparatus for aligning a fiber tip of an optic fiber in position with respect to a fiber communications circuit disposed on a carrier having a planar surface. In the method, the steps include supporting the optic fiber with a block having a planar surface such that a movement of the block causes a corresponding movement of the fiber tip. The steps further include placing the planar surface of the block in contact with the planar surface of the carrier, thereby defining a reference plane between the block and the carrier. Finally, after the placing step, there is the steps of automatically establishing a first relative position between the block and the carrier along a first dimension of the reference plane, and automatically establishing a second relative position between the block and the carrier along a second dimension of the reference plane, wherein the second dimension is orthogonal to the first dimension.

Abstract: Switched video broadband service and narrowband telecommunications service are integrated and provided directly to subscribers. A plurality of video channels are provided to a central office by a video service provider, and said video channels are transmitted to a remote terminal using standard FM video supertrunks. At the remote terminal, video channels selected by a group of subscribers are frequency-division multiplexed with baseband signals of narrowband telecommunications service and are transmitted over a single fiber to an optical network unit adjacent the living units of the group of subscribers. The subscriber selected channels are then demultiplexed and provided to the living units via coaxial drops, along with the narrowband telephone service provided on twisted pairs. Channel requests from the group of subscribers are combined and transmitted upstream in a single narrowband video control channel.

Abstract: Optical transmit amplifier (24) fault indicator system (46), (78), and (80) indicates the failure of optical transmit amplifier (24) and includes an input loss circuit (46), an output failure circuit (80), and a modulation detector circuit (78). The modulation detector circuit (78) receives a portion (76) of the optical output signal (74) for determining therefrom that a failure in modulation exists in optical output signal (74) of optical transmit amplifier (24). The modulation detector (78) includes a modulation conversion circuit (82) and (84) for converting modulation in the optical output signal (76) into a measurable signal having a level within a first predetermined range in the presence of modulation and a second predetermined range in the absence of modulation. The modulation detector circuit (78) converts the measurable signal to a DC signal and produces a loss of modulation alarm signal (114) in response to a loss of modulation.

Abstract: A method of communicating serial information from a source to a destination is disclosed. In one embodiment, the method involves numerous steps for communicating serial information from a source to a destination. First, transmission is commenced of a serial stream of status information from the source to the destination, wherein the serial stream of status information has a beginning, an end, and a plurality of serially ordered status units between the beginning and end. Second, after the first step, a serial stream of control information is transmitted from the source to the destination, wherein the serial stream of control information has a beginning and an end. Various receiving steps then follow. First, the destination receives the beginning and a first portion of the plurality of status units of the serial stream of status information. Second, the destination receives the serial stream of control information.

Abstract: A communication system is provided for the distribution of switched video, along with telephony and control information, over fiber from a central office to a subscriber premises. The system can dynamically allocate video channels to subscribers using a pool of switched channel selector units located at the central office, thus permitting increased sharing of video distribution resources and controlling access to all channels. The system can provide a multiplicity of simultaneously available switched channels at each subscriber premises from a selection of over a hundred channels available at the central office. Subscribers are connected to the switched video service through a switched video distribution system rack. Switched channels will travel over single-mode fiber in AM/VSB format compatible with subscriber video equipment.

Abstract: A desynchronizer (20) for desynchronizing data stored within synchronous payload envelopes of a synchronous communication protocol such as SONET (Synchronous Optical Network), provides for smoothing the periodically discontinuous clock signal associated with that data after the synchronous communication protocol overhead has been removed. The desynchronizer accommodates for shifts in the position of the payload envelope and hence, the data within the synchronous communication frame as well as adjustments within the data itself due to asynchronous bit stuff information.

Abstract: Start-up control circuit (152) regulates the output voltage (V.sub.OS) of a power supply circuit (150). Magnetic amplifier control circuit (54) includes magnetic amplifier (42) and error detection circuitry (58, 68, and 70). Start-up control circuit (152) includes sensing circuitry (76 and 184) for generating sensing signals in response to voltage levels (V.sub.CC and V.sub.EE) in error detection circuitry (58, 68, and 70). Sensing signals indicate whether error detection circuitry (58, 68, and 70) voltage levels are sufficient to drive magnetic amplifier control circuit (54). Reset circuitry (190 and 192, and 194) associates with the sensing circuitry (76 and 184) for initially resetting magnetic amplifier (42) to prohibit output voltage (V.sub.OS) from power supply circuit (150) when the sensing signals indicate that voltage levels are insufficient for error detection circuitry to drive magnetic amplifier control circuit (54).

Abstract: In a telecommunications system providing switched video services, a video line card includes a switch arrangement for selecting a plurality of channels from a greater plurality of available channels and for providing said selected channels in a fixed bandwidth that may be received by a subscriber. A plurality of tuners are used to select the channels and to provide the channels on an intermediate frequency, which frequency is thereafter converted to a distribution channel frequency acceptable by the subscriber.

Abstract: In one embodiment, the present invention includes a method of increasing the attachment bond strength between a first and second object comprising respective first and second materials. Each of the first and second materials has a respective first coefficient of thermal expansion at an assembly temperature, and a second coefficient of thermal expansion at an operational temperature. The method has various steps (FIG. 4). An attachment surface of the first material is configured to be nonplanar (FIG. 3a, 36, 37). The second material is brought to a contact point with the attachment surface of the first material (FIG. 3b, 46). The first and second materials are heated at the contact point to the assembly temperature whereby at least one of the materials is caused to flow in response to the heat.

Abstract: A transformer designed for 1:N voltage transformation (where 1:N may be any rational number) at high frequencies (such as over 7 megahertz) can achieve acceptable frequency response and attendant improved values of signal attenuation and signal distortion by physically separating two or more sets of electrically tightly coupled windings and connecting one winding of different sets in parallel and the other winding of the same sets in series. This interconnection of windings to achieve a 1:N transformation ratio reduces the negative effects of the interwinding capacitance thereby providing the improved frequency response.

Abstract: Feedback signals for use in controlling a variable gain amplifier portion of a radio receiver are obtained from existing automatic gain control signals comprising a part of a time domain equalizer section of a receiver such that bandpass filtering and feedback signal detecting circuitry, along with detector circuitry linearization apparatus required in prior art feedback schemes, can be eliminated from the overall scheme. The resulting apparatus provides a constant level to the input of the incorporated analog-to-digital converter and the resultant loop adapts to changing RF/baseband bandwidths.

Abstract: A method and system to connect an optical network unit with a plurality of user sites. The invention includes the steps of and circuitry for connecting a plurality of line circuits to a cross-connect matrix. The optical network unit contains both the line circuits and the cross-connect matrix. In the invention, a plurality of drop connectors connect the cross-connect matrix to a plurality of user sites such as homes. The method and system further include circuitry that remotely controls the cross-connect matrix from a central office or network management system to connect selected ones of the line connectors to selected ones of the drop connectors and, thereby, electrically connect the optical network unit to the plurality of user sites.

Abstract: A method and apparatus are provided for smoothing jitter in a smoothed clock output by routing a portion of the incoming clock signal representing phase hit information through a digital high-pass filter (12), which produces complementary output digital signals. One of the output signals includes the higher order bits of the filtered phase hit signal, and the other output signal includes the lower order bits of the filtered phase hit signal. The filtered, complementary phase hit signals are summed with the stream of clock pulses to be smoothed. Each of these summed signals is supplied to a separate phase detector circuit (120, 121). The phase detector (120) receiving the higher order bit signal generates a coarse error signal, and the phase detector (121) receiving the lower order bit signal generates a fine error signal.