Teradyne, Inc.

Bernard M Cuddy

Brian Charles Wadell

A microwave synthesizer includes a drift-cancel loop having a narrow-band input, a low-frequency comb input, a wide-band input, and an output for providing an adjustable-frequency output signal. A narrow-band synthesizer is coupled to the narrow-band input, and a comb generator is coupled to the low-frequency comb input. Instead of using a wide-band synthesizer to drive the wide-band input, as conventional topologies have done, the instant invention employs a highly stable, low noise high frequency oscillator. The output of the oscillator is mixed with the output of the comb generator to produce low-noise, high frequency combs. The low-noise, high frequency combs are then used to drive the wide-band input of the drift-cancel loop. Significant reductions in phase noise can be achieved as compared with conventional designs.

Low noise microwave synthesizer employing high frequency combs for tuning drift cancel loop

An attenuating circuit including a reference signal path that is attenuated by an amount which is related to the attenuation in an attenuation signal path for the purpose of improving attenuation accuracy.

Attenuating circuit

Electrical circuitry support apparatus including a card cage having slots for removably receiving circuit boards, and a plurality of circuit boards in the slots, at least one circuit board being a high-frequency board carrying an enclosure containing a high-frequency device. The enclosure provides shielding inhibiting transmission of high-frequency signals to or from the device.

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Cambridge, MA, United States of America

Bernard M Cuddy