A Fast Coincident Current Magnetic Core Memory

This paper describes a coincident current magnetic core memory with a capacity of 16,384 words, of 27 bits each and a cycle time of 1.2 μsec. It utilizes 30-mils ferrite toroid cores with low temperature coefficient, allowing operating temperature up to 75°C, thus eliminating the need for cooling equipment. The drive and sense system of the memory is unusually simple. The main concepts which enhance simplicity are a simple method for eliminating the capacitive noise currents in a transformer matrix, and, further a drive module with a floating output is used both for the entire selection system and as an inhibit driver. In the sense amplifier, the dc restoration has been done by gain control without loss of speed. These features are described in some detail, while the other rcircuitry is mentioned for completeness, but only briefly.