Agilent Technologies, Inc.

Christopher George Helt

David Lawrence Linam

Guy Harlan Humphrey

Gayvin E Stong

Guy Marian Humphrey

An electronic circuit for enabling differential tests. In representative embodiments, the electronic circuit includes a first differential receiver having first and second inputs and an output, a first switch having first and second data inputs, a control input, and an output, and a first control device having an output. The first input of the first differential receiver is connected to a first contact and to a first single ended receiver input, and the second input of the first differential receiver is connected to a second contact and to a second single ended receiver input. The first data input of first switch is connected to first single ended receiver output, and the second data input of first switch is connected to first differential receiver output. The first control device output is connected to first switch control input. When first control device output is in a specified condition, first data input of first switch is connected to first switch output, otherwise second data input of first switch is connected to first switch output.

Differential self-test of input/output circuits

A circuit and method that maintains the impedance matching characteristics of a common output driver while compensating for the high-frequency signal attenuation inherent in printed circuit board traces and other integrated circuit signal transmission media are disclosed. The circuit includes a pre-emphasis driver configured in parallel with a standard output driver. The pre-emphasis driver is a tri-statable device which mirrors a received logic input when in an &ldquo;on&rdquo; state and provides a high output impedance with no signal content when in an &ldquo;off&rdquo; state. The pre-emphasis driver is controlled by a pre-emphasis control signal configured such that the pre-emphasis driver can inject high-frequency signal components into a transmission line for a portion of a clock cycle. The pre-emphasis control signal is configured such that the pre-emphasis driver turns &ldquo;on&rdquo; in close approximation with data signal transitions and is turned &ldquo;off&rdquo; before a reflected signal caused by the impedance mismatch between the pre-emphasis driver and downstream elements (i.e., a transmission line and a receiver) appears at the parallel driver output. In its broadest terms the method includes: providing a data signal at a matched-impedance driver; placing a low-impedance driver in parallel with the matched-impedance driver; using a control signal to turn &ldquo;on&rdquo; the low-impedance driver when the data signal transitions and turn &ldquo;off&rdquo; the low-impedance driver before an impedance mismatch induced reflected signal returns at the output of the matched-impedance driver.

Circuit and method for compensation if high-frequency signal loss on a transmission line

An apparatus and method permits quick response to a transition at an input port and subsequent propagation of the transition to the output port while being able to process a wide variety of input signal properties. A receiver apparatus comprises at least first and second receivers, each receiver accepting an input signal and tuned for optimal response to a set of known input signal properties. Either first and second primary transition propagation elements or secondary transition propagation element propagates a first transition from one of the receivers. A universal transition propagation element propagates the first transition to an output. A pass gate receives a signal based upon the output and inhibits transmission of the signal based upon the output until the first and second intermediate signals are equivalent whereupon the pass gate is placed in low impedance state permitting the signal based upon the output to be held in a storage node as the preset signal.

Receiver apparatus and method of propagating a signal

An electronic circuit and method for processing a signal, including a variable-delay transmission gate for receiving a binary input signal and propagating a delayed binary output signal corresponding to the input signal. The propagation delay in the transmission gate is controlled by two complimentary, non-binary, control signals from a current mirror that is driven by a PVT-compensated voltage follower.

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Fort Collins, CO, United States of America

Christopher George Helt