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Core Plane Tester with Impedance Matching

IP.com Disclosure Number: IPCOM000091239D
Original Publication Date: 1967-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Crandell, AJ: AUTHOR [+2]

Abstract

In this circuit, two drivers are connected to apply current pulses to a test subject, typically a ferrite core memory. The test pulses are full-select read and write currents and half-select disturb currents. The circuit couples drivers that are used for resistively terminated loads of about 50 ohms to a memory that has transmission irregularities and has an average impedance higher than 50 ohms.

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Core Plane Tester with Impedance Matching

In this circuit, two drivers are connected to apply current pulses to a test subject, typically a ferrite core memory. The test pulses are full-select read and write currents and half-select disturb currents. The circuit couples drivers that are used for resistively terminated loads of about 50 ohms to a memory that has transmission irregularities and has an average impedance higher than 50 ohms.

Impedance ZL3 represents the transmission line characteristics of the memory and a twisted wire pair leading to the memory. Resistor Rt is the termination for the drive lines of the memory. In the example, the drive line is directly connected to ground at the end remote from the drivers.

Transformer X3 couples the memory to the test circuit. Such transformer is part of the test apparatus and corresponds to a similar transformer in the memory drive circuit. The primary winding of transformer X3 is center-tapped and can be driven from either end to apply pulses of either polarity to the memory. The two halves of the primary winding are coupled to the drivers through directional couplers K1 and K2, impedance matching transformers X1 and X2, and transmission lines. The latter are represented schematically by their impedances ZI1, ZI2, ZL1, and ZL2. Impedances ZI1 and ZI2 correspond to the driver impedance. Impedances ZL1 and ZL2 correspond to the load impedance.

Transformers X1 and X2 provide suitable impedance matching between the l...