Marconi Communications Gmbh

Avo Multi-amp Corporation

Reliance Comm/tec Corporation

Gerald Wayne Beene

Philip L Dillon

A method for improved cable resistance measuring is provided including coupling a measurement test device including a master unit and a remote unit, via at least one connector, to at least one network cable and determining a terminating impedance using field calibration. The method additionally including transmitting an AC signal across the network cable for determining a resistance of the network cable, and measuring a length of the network cable. The method still further including measuring a capacitance of the network cable, and measuring an impedance of the network cable terminated by the measurement test device. The method additionally including extracting the resistance of the network cable from the impedance measurement, and correcting for error in at least one of capacitance, termination resistance, and nominal cable effects for a corrected resistance value.

System and method for resistance measurement

A device for testing data communications cabling. The device consists of a signal generator that can generate a test signal to test the data communications cabling and a receiving component that can receive a reflected signal produced by reflection of the test signal from the data communications cabling including any reactive point source disturbance that may exist on the cabling. The receiving component can determine characteristics of the reflected signal by analyzing the phase rotation and amplitude of the reflected signal. The device can also include a cancellation generator that can generate a cancellation function based on the characteristics of the reflected signal. The cancellation function can substantially negate a portion of the reflected signal.

Connector crosstalk and return loss cancellation

A surge protection circuit is coupled to the wires that transport digital signals between a local unit, such as an ONU, and a remote unit, such as a NID. The surge protection circuit includes a coordinating impedance having a capacitive element connected in series with the twisted pair wires coupling the ONU to the NID. The coordinating impedance couples a primary shunt protector and a secondary shunt protector. Various embodiments of the surge protection circuit comprise coordinating impedance devices including a series connected: capacitor and resistor, capacitor and inductor, and capacitor, inductor, and resistor. By using a capacitive element in the coordinating impedance, the signal loss through the surge protector is significantly reduced for 10 Base-T and 100 Base-T Ethernet systems. Further, the added inductance may become part of an integrated low-pass filter that further reduces signal loss at high frequencies.

Reduced signal loss surge protection circuit

A current limiter is provided that includes a power switch for receiving input power from a power source and passing at least a portion of the input power to an output, a current sense mechanism coupled to the power switch for sensing current flowing through the current limiter and for providing a current flow signal related to the current flow through the current limiter, and a control mechanism coupled to the power switch that causes the power switch to reduce the current flow when the current flow signal indicates that the current flow exceeds a first current flow level. In one embodiment the current limiter may include a voltage sense mechanism that senses the voltage drop across the input to output of the device and use a reference voltage and a control loop to maintain the voltage drop relatively constant at all load currents. In another embodiment the current limiter may include a timing mechanism that provides a timing signal that is used by the control mechanism to cause the power switch to block power transmission to the load. In yet another embodiment the current limiter may include a temperature sensing mechanism that provides a first temperature signal that is used by the control mechanism to cause the power switch to block power transmission when the temperature signal indicates that a monitored temperature exceeds a reference temperature. Optionally, the current limiter may include a surge voltage protection mechanism that blocks high voltage power surges from the output. Also, the current limiter may include short circuit protection means.

Current limiter

An electronic ringing generator circuit with provision for power efficient current limiting and preservation of sinusoidal or near sinusoidal output waveform under overload conditions. A pulsewidth modulated DC-DC power convertor produces supply voltages for a linear class B power amplifier which has a low frequency low level sinusoidal signal applied to its input through a first controllable attenuator. The DC-DC convertor's reference input is also driven through a second controllable attenuator which is coordinated with the first controllable attenuator. The attenuators are operated in such a way that if the amplifier's output current exceeds a predetermined value, both the input signal and amplifier supply voltages are reduced in a coordinated manner so that simultaneously the output AC waveshape is preserved and the amplifier continues to operate at or very near optimum efficiency. The amplifier may be operated to produce a sinusoidal output (crest factor =1.41) or a slightly clipped sinewave with a specified minimum crest factor less than 1.41.

Growing community of inventors

Southlake, TX, United States of America

Gerald Wayne Beene