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Series-Parallel Transformer

IP.com Disclosure Number: IPCOM000039259D
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Tesche, CD: AUTHOR

Abstract

Optimum signal-to-noise ratios and voltmeter source resistances at input frequencies are obtained by using a planar series-parallel transformer to couple pick-up loop inductance and that of the input coil to a superconducting quantum interference device (SQUID). In DC SQUID magnetometers, the most favorable signal-to-noise ratio is obtained when pick-up coil inductance equals the SQUID input coil inductance. In DC SQUID voltmeters, the preferred source resistance is proportional to the product of the signal frequency and the input coil inductance. These relationships can be obtained by planar transformer in the figure, where the primary winding includes a plurality of smaller windings LP1-LP4 in series to increase inductance and is coupled to the pick-up coil L .

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Series-Parallel Transformer

Optimum signal-to-noise ratios and voltmeter source resistances at input frequencies are obtained by using a planar series-parallel transformer to couple pick-up loop inductance and that of the input coil to a superconducting quantum interference device (SQUID). In DC SQUID magnetometers, the most favorable signal-to-noise ratio is obtained when pick-up coil inductance equals the SQUID input coil inductance. In DC SQUID voltmeters, the preferred source resistance is proportional to the product of the signal frequency and the input coil inductance. These relationships can be obtained by planar transformer in the figure, where the primary winding includes a plurality of smaller windings LP1-LP4 in series to increase inductance and is coupled to the pick-up coil L . The transformer secondary includes a corresponding plurality of smaller windings LS1-LS4 all parallel to SQUID input coil inductance Li to decrease inductance. For the primary winding, the inductance Lp=kLP that approximates pick-up coil inductance, where LP is the primary inductance and is the number of smaller windings. This insures maximum input signal transfer. Considering the secondary winding, its inductance Ls is approximated by secondary winding inductance LS/k. The mutual inductance M thus becomes M2=a2 Ls (Lp) With the above structure, the total required area for a planar transformer decreases approximately in the relationship of 1/k. Secondary winding inductance Ls...