Browse Prior Art Database

Cryogenic Sampling Device

IP.com Disclosure Number: IPCOM000097565D
Original Publication Date: 1961-Feb-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Cheng, TH: AUTHOR

Abstract

The sampling device measures high speed wave forms in cryogenic circuits. The wave to be measured is applied to a transmission line formed by a strip A and a shield (not shown) on which the circuit is mounted. The sampling signal is applied to a transmission strip B. Lines A and B are arranged to apply their combined magnetic fields to a gate G connected in the measuring circuit. The characteristic of G and the magnitude of the sampling signal are such that the field produced by the sampling signal biases the gate just past the toe of its rather broad transition curve.

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Cryogenic Sampling Device

The sampling device measures high speed wave forms in cryogenic circuits. The wave to be measured is applied to a transmission line formed by a strip A and a shield (not shown) on which the circuit is mounted. The sampling signal is applied to a transmission strip B. Lines A and B are arranged to apply their combined magnetic fields to a gate G connected in the measuring circuit. The characteristic of G and the magnitude of the sampling signal are such that the field produced by the sampling signal biases the gate just past the toe of its rather broad transition curve.

The measuring circuit itself includes two parallel paths 10 and 12 which, with the shield, also form transmission lines. Initially, current from source 18 is directed through 10 by energizing reset source 16 to introduce resistance into a gate portion of 12. The sampling pulse is then applied to B having a predetermined time relationship to the wave form on A to be measured. The field produced by the wave form on A is sufficiently small to be of itself ineffective to drive C resistive and is preferably smaller than the width of the transition curve of the gate. The amount of resistance introduced into C varies with the magnitude of the portion of the wave in A which is sampled by the signal applied to B. The gate exhibits, for example, a resistance R(1) if the portion of the wave sampled has a current magnitude I(1).

The amount of current transferred to 12 varies according...