Northern Telecom Limited

Nortel Networks Corporation

Other

Anthony K Brown

Richard R Goulette

Terry E Newell

Lawrence H Sasaki

Rodney David Pike

John M Williamson

Roderick Edgar Wallace

Robert Zani

Alexandre J Guterman

A Brillouin analysis sensor system comprising: a Brillouin analysis sensor; a polarization beam splitter/combiner, operably connected to the Brillouin analysis sensor between the sensor and the sensing fiber, for receiving polarized lightwaves from the sensor, combining the lightwaves and launching combined lightwaves waves in the sensing fiber a first direction, and a phase conjugate mirror at a free end of the sensing fiber for receiving combined lightwaves from the polarization beam splitter/combiner, rotating the polarization of the combined lightwaves and launching the rotated combined lightwaves in the sensing fiber in an opposing direction to the first direction.

System and method for Brillouin analysis

A digital data driver includes a differential amplifier having transistors which operate as a push-pull amplifier in class C mode. The transistors are conductive or non-conductive and controlled in response to a differential data input signal. The driver provides current to a load resistor of an external equipment and the direction of the current flowing therein is reversed in response to the input data. The differential amplifier transistors are connected to other transistors which provide source impedance to the external equipment. The source impedance of the driver is a controllable characteristic impedance of e.g., 50 .OMEGA..

Differential data driver

A data pulse receiver for detecting and amplifying substantially attenuated data pulses received at gigabit-per-second rates from a differential coupler with outputs having asymmetrical dc characteristics. The receiver, in a preferred embodiment, has grounded base differential amplifiers to give impedance matching, a biasing resistor connected to a separate ground terminal for biasing one of the differential amplifiers, and a matching resistor, connected at only one of its terminals, to compensate for the stray capacitance of the biasing resistor. A regenerative flip-flop with programmable tail current provides hysteresis in order to suppress unwanted noise. The receiver may also include means for automatic adjustment of the hysteresis level.

Multi-GB/S data pulse receiver

A gyrator includes shunt or feedback nodal capacitors and shunt lossy inductors without shunt load resistors. The effective nodal capacitance is reduced by the introduction of the shunt lossy inductors. The inductors act to discriminate against injected power supply noise, resulting in improved oscillator phase noise. The inductors produces less drop dc voltage than the resistive load, so that larger linear oscillation is obtained with improved oscillator phase noise.

Gyrator with loop amplifiers connected to inductive elements

A bus for high signal quality interconnections, comprising means for producing at least one common mode reflection, often for differential transmission line interconnections. Also, a bus for high signal quality interconnections further comprising means for under-damping the signal and/or reducing the common mode noise. In both cases the means are at least one impedance termination. To produce common mode reflections, there are non-contact couplers terminated by short and open circuits, which cause the reflections from via connectors and other like impedance discontinuities to be re-reflected in common mode so that they are rejected by a differential receiver. To produce under-damping of the signal and/or a reduction of the common mode noise, capacitive terminations are used. The under-damping of the signal sharpens in the falling edge of the coupler pulses.

Noise cancellation modification to non-contact bus

A data pulse receiver for detecting and amplifying serial data pulses received at gigabit-per-second rates over a transmission medium through which the signal levels have been substantially attenuated. The receiver, in a preferred embodiment, has grounded base differential amplifiers to give impedance matching, signal amplification and wide frequency bandwidth. A regenerative flip-flop with programmable tail current provides hysteresis in order to suppress unwanted noise signals. The flip-flop also returns the data pulses to NRZ format. The receiver may also include means for automatic adjustment of the hysteresis level.

Serial multi-GB/s data receiver

A transconductance amplifier for use in a low noise, microwave voltage controlled oscillator. The transconductance amplifier incorporates a linear amplifier having ratioed transistors to provide linearized gain. A tuning arrangement combines in-phase and out of phase currents in an inverse ratio to provide a constant D.C. current sum. The tuning circuit has been arranged to operate without a cascode stage such that the power supply voltage requirement is reduced from 5.0 volts to 3.3 volts.

Microwave VCO having reduced supply voltage

A microwave multiphase detector for demultiplexing and regenerating data from an incoming data stream includes N data channels and has a data rate R. For recovering data corresponding to a channel M, a detecting unit receives the data stream, detects a sampling phase corresponding to a data transition on channel M and generates a phase width modulated (pwm) pulse, phase modulated with the sampling phase. A digital to analog (D/A) conversion unit converts the pwm pulse to a contributing control voltage and a data regeneration unit provides a recovered data bit for channel (M). The detector is supplied with N variants of a local clock signal with a rate R/N, each variant being phase displaced with .+-.360.degree./N from the adjacent variants. A counterbalancing unit is also provided for each channel, such that if a pwm pulse is indeed generated, the contributing voltage for that pulse is compensated for with a balance pulse of opposed amplitude. In this way, the sampling phase corresponding to the respective M data channel may be adjusted by varying the ratio between the amplitudes of the pwm pulse and the balance pulse.

Microwave multiphase detector

A microwave differential amplifier comprises a first and a second matched NMOS device, each connected with the source to a common bias node, the gate to an input port for receiving a differential input signal and with the drains to an output port for providing a differential output signal. The Miller capacitors of each device provide the necessary feedback between the input and output ports for shifting the phase of the differential output signal with respect to the phase of the differential input signal with 45.degree. at a predetermined frequency. The operating point of the NMOS devices is maintained in the linear region of the respective transfer characteristic, using matched loads and a corresponding bias current. The loads may be resistors, in which case AGC is used for maintaining a constant bias current, or active loads. A VCO built with four such differential amplifiers in a gyrator configuration oscillates at the predetermined frequency and has eight output signals. The VCO may be used in circuits providing multiphase data regeneration where the number of data transitions exceeds the number of clock transitions in a given time period.

CMOS microwave multiphase voltage controlled oscillator

A low noise linear amplifier and a microwave voltage controlled oscillator constructed from such amplifier. Each amplifier within the VCO utilizes a ratioed transistor configuration to generate a linear output over a wide range of inputs. Output current from the amplifier is split into a main output current and components of in-phase and 180.degree. out-of-phase current. A logarithmic tuning control combines the components of in-phase and 180.degree. out-of-phase currents in inverse ratio to provide a constant d.c. feedback current.

Second generation low noise microwave voltage controlled oscillator

A linear bipolar junction transistor amplifier. The linear gain is achieved by an offset voltage created by ratioed transistors wherein the ratio is an integer. The ratios are achieved either by connecting equal transistors in parallel or by employing multiple emitters on a single transistor. This results in a linear amplifier which is substantially independent of manufacturing process tolerance variations as well as power supply and temperature variations.

Linear bipolar junction transistor amplifier

A low power (10 mW), high-speed (50 Mb/s) digital driver is formed from three analogue components: level shifter to limit the output swing, waveshaper to limit the slew-rate of the output transition, and a Class AB output stage to buffer the signal. The components afford flexibility to meet the demands of different applications. The driver can be limited to 1V swing for terminated applications such as for backplanes, or it can be limited to 1V swing for unterminated applications such as intraboard (PCB) communication.

Digital driver with class AB output stage

A gyrator based resonator comprises first and second differential amplifiers cross coupled to form a quadrature phase voltage controlled oscillator. The differential amplifier circuits include matched transistor pairs and associated transconductance adjusting components to control the resonant frequency of the resonator. Transconductance delay and admittance loss elements are also provided and these elements serve to control the loop gain of the resonator. A loop gain greater than unity results in the resonator oscillating while a loop gain less than unity produces a bandpass filter. A resonator having gain less than unity may be slaved to a similar resonator having gain adjusted to be greater than unity thus creating a low noise oscillator and tracking filter.

Low noise oscillators and tracking filters

A differential amplifier includes a bias current source and a current dividing circuit for controllably dividing a bias current between first and second current paths. A first pair of matched transistors is connected as a differential pair between matched load impedances and the first current path. A second pair of matched transistors is connected as a differential pair between the matched load impedances and the second current path. Differential inputs of the second differential pair are connected to corresponding differential inputs of the second differential pair. The transistors of the first and second pairs have different emitter areas. Matched capacitors may be connected between respective differential inputs and differential outputs of the differential amplifier. The load impedances may be tapped to provide outputs having a lower differential gain. The differential amplifier is useful for building resonant circuits, for example voltage controlled oscillators having high Q factors.

Differential amplifier and high frequency resonant circuits constructed

A resonant circuit comprises first and second amplifiers. An input of the second amplifier is coupled to an output of the first amplifier, and an output of the second amplifier is cross-coupled to an input of the first amplifier. The first amplifier has a first gain and a 90 degree phase shift between its input and its output at a resonant frequency of the resonant circuit. The second amplifier has a second gain and a 90 degree phase shift between its input and its output at the resonant frequency of the resonant circuit. The second gain is different from the first gain. The resonant circuit can have a first port and second ports coupled to an input and an output respectively of one of the first and second amplifiers. Because the gains of the first and second amplifiers differ, the gain from the first port to the second port of the resonant circuit will differ from the gain from the second port to the first port. This gain difference is useful for enhancing the quality factor Q of multiple resonator circuits constructed from such resonant circuits.

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Kanata, Canada

Anthony K Brown