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Browse Prior Art Database

Read/Write Switch With Remote Write Driver

IP.com Disclosure Number: IPCOM000081090D
Original Publication Date: 1974-Apr-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Barsotti, RH: AUTHOR [+2]

Abstract

Magnetic read/write head 10 for transducing magnetic storage medium is remotely located relative to write driving transistors 12 and 14. Transistors 20 and 22 provide correct loading to write drive cable 16 during write and provides a low-impedance connection between head 10 and read preamplifier 18 during read. Resistor 15 provides impedance match to cable 16 at the sending end of the cable.

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Read/Write Switch With Remote Write Driver

Magnetic read/write head 10 for transducing magnetic storage medium is remotely located relative to write driving transistors 12 and 14. Transistors 20 and 22 provide correct loading to write drive cable 16 during write and provides a low-impedance connection between head 10 and read preamplifier 18 during read. Resistor 15 provides impedance match to cable 16 at the sending end of the cable.

During the write operation, the write switch line is high providing additional bias voltage to bases of transistors 20 and 22. This additional bias voltage operates the transistors 20 and 22 at an optimum DC level, to prevent write signal transients from saturating the transistors 12 and 14. Transistors 20 and 22 being located between the head 10 and the cable 16 also permit control of the termination impedance of cable 16, by isolating the head inductance from the cable load.

During the read operation, the write switch line is open circuit. Bias to transistors 20 and 22 is then due to +V at resistor 24. Resistors 24, 25 and 26 are chosen along with transistors 20 and 22, such that the transistors saturate with almost no DC collector current when properly biased at their bases. With transistors 2O and 22 saturated, they provide a low-impedance connection between head 10 and preamplifier 18 for the read signal.

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