Agilent Technologies, Inc.

Hewlett-packard Company

David Paul Kjosness

Joe E Marriott

Bryan D Boswell

Virgil George Leenerts

Feng Gao

Gerald Irwin Raak

Patrick H Adams, Iii

A digital pulse generator including a fractional delay filter is provided as having a plurality of step response functions that can be selected on a sample by sample basis by selection of filter coefficients. The step response functions are all identical but each have different group delay. Responsive to an input waveform having leading and trailing edges aligned with a system clock, the fractional delay filter can output the impulse responses as a pulse waveform having respective leading and trailing edges delayed by different respective fractions of a signal clock cycle from the respective leading and trailing edges of the input waveform. The pulse waveform as output can thus have desired pulse width and desired period of repetition with finer edge placement resolution of improved accuracy.

Pulse generator with precision edge placement

An exponential signal generator having a memory, a scale unit and an adder. A value stored in the memory is scaled and added to itself to produce a new value for storing in the memory. The exponential signal is represented by the exponential value.

Method and apparatus for producing an exponential signal

An isolated direct-current to direct-current (DC-to-DC) converter and associated method are provided which employ a class-D amplifier. An alternating current (AC) input voltage and a DC input voltage drive the class-D amplifier to produce an AC primary voltage. The AC primary voltage then drives a primary winding of a transformer, thereby generating an AC secondary voltage at a secondary winding of the transformer. The AC secondary voltage then drives a rectifier, yielding a rectified voltage. A low-pass filter is then accepts the rectified voltage to produce a DC output voltage.

Isolated DC-to-DC converter

A switching network for coaxial transmission lines switches both the center conductors and the shields to allow floating measurements and eliminate the effects of ground loops. The shields are switched even though the coaxial relays use to switch the center conductors do not themselves also switch the shields. This is accomplished by using two coaxial relays having connected center conductors, each of which coaxial relay is itself shielded, and a third relay to selectively connect and disconnect the shields of the coaxial relays. All three relays open and close in unison. Although this arrangement provides excellent isolation when open within the circuit where it is used, there is unfortunatly a coupling mechanism between pairs of such circuits having such relay arrangements that are closed. This coupling mechanism produces crosstalk between such pair of circuits. The crosstalk current tends to flow in a resonant circuit. Both the resonant peak of the crosstalk current and its non resonant magnitude can be reduced by the inclusion of magnetic cores (such as lossy ferrites) around the coaxial transmission lines as they enter and leave the coaxial relays.

Coaxial switching system with switched shields and crosstalk suppression

A switching network for coaxial transmission lines switches both the center conductors and the shields to allow floating measurements and eliminate the effects of ground loops. The shields are switched even though the coaxial relays used to switch the center conductors do not themselves also switch the shields. This is accomplished by using two coaxial relays having connected center conductors, each of which coaxial relay is itself shielded, and a third relay to selectively connect and disconnect the shields of the coaxial relays. All three relays open and close in unison. Although this arrangement provides excellent isolation when open within the circuit where it is used, there is unfortunately a coupling mechanism between pairs of such circuits having such relay arrangements that are closed. This coupling mechanism produces crosstalk between such pairs of circuits. The crosstalk current tends to flow in a resonant circuit. Both the resonant peak of the crosstalk current and its non resonant magnitude can be reduced by the inclusion of magnetic cores (such as lossy ferrites) around the coaxial transmission lines as they enter and leave the coaxial relays.

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Longmont, CO, United States of America

David Paul Kjosness