Abstract: A differential system producing differential signals with offset cancellation utilizing a double differential input pair system is disclosed. It uses two parallel differential transistor pairs which are intentionally skewed. Nominally, the differential pairs are skewed in opposite direction from each, but with equal magnitude, so that the combination of the two differential pairs is nominally balanced. The current through each differential pair is then increased or decreased until any offset is sufficiently cancelled, using a selection means for providing an equi-potential value to first and second differential inputs in a calibration mode of the system and a comparison means for comparing first and second differential outputs in a calibration mode to determine the offset of the system.

Abstract: A differential system producing differential signals with offset cancellation utilizing a double differential input pair system is disclosed. It uses two parallel differential transistor pairs which are intentionally skewed. Nominally, the differential pairs are skewed in opposite direction from each, but with equal magnitude, so that the combination of the two differential pairs is nominally balanced. The current through each differential pair is then increased or decreased until any offset is sufficiently cancelled, using a selection means for providing an equi-potential value to first and second differential inputs in a calibration mode of the system and a comparison means for comparing first and second differential outputs in a calibration mode to determine the offset of the system.

Abstract: A Network Interface Card (NIC) for attaching data terminal equipment to a communications network. The NIC includes a Phase Lock Loop (PLL) with a master delay structure that is operatively coupled to at least one delay line structure. The PLL generates control pulses at precise delayed intervals that are used to gate data through said at least one delay line structure.

Abstract: A system that generates data waveforms for transmission on a communications network includes a series of sequentially over sampled and switch current sources whose timings are locked to a master delay line and replicas thereof. The master delay is configured as a ring oscillator with its frequency looked to a precise clock reference. The clock controls the rise and fall of the data waveforms thus making them immune to variations in semiconductor processes used to implement the system.

Abstract: A delay circuit arrangement includes a delay cell and controller. The delay cell includes a differential pair of N-Channel devices and P-Channel devices coupling the differential pair to positive voltage rail. The controller provides conductivity adjustment in the P-Channel devices. Adjustment of the delay is made by adjusting the current in a device biased in its linear region and coupling the differential devices to a ground potential.

Abstract: A method and apparatus for equalizing a communications signal transmitted through a transmission medium includes an integrated continuous-time filter and circuitry for developing a feedback signal to compensate for distortion in the signal caused by the transmission medium. The control signal adjusts the transfer characteristics of the integrated continuous-time filter thereby compensating for loss and distortion of the signal caused by the transmission medium and further tunes the integrated continuous-time filter thereby compensating for semiconductor process variations in the integrated continuous-time filter.

Abstract: A method and apparatus for reducing reference frequency signal and/or clock switching noise in self-tuned integrated continuous-time filters. In the master-slave automatic tuning scheme, one or more sample-and-hold circuits sample and hold the frequency control signal and Q-control signal generated by the feedback loop(s) of the automatic tuning system. The control signals are held at a constant level for a period of time during which the reference frequency signal and/or clock signal are quiescent. At one or more predetermined times, the frequency control and Q-control signals are intermittently updated to automatically tune the slave filter.