Browse Prior Art Database

Signal Sampling of Pulse Biased MR Head

IP.com Disclosure Number: IPCOM000087444D
Original Publication Date: 1977-Jan-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Schwartz, TA: AUTHOR

Abstract

The pulse biasing of a magnetoresistive (MR) element for a magnetic transducing element allows a reduction in the power dissipation of the MR element without a Loss of signal amplitude by using sample and hold circuits connected at the outputs to each terminal of the MR element. The MR elements may be the conventional center-tapped, as shown in Fig. 1, noncenter-tapped, as shown in Fig. 2, or a shared terminal configuration, as shown in Fig. 3.

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Signal Sampling of Pulse Biased MR Head

The pulse biasing of a magnetoresistive (MR) element for a magnetic transducing element allows a reduction in the power dissipation of the MR element without a Loss of signal amplitude by using sample and hold circuits connected at the outputs to each terminal of the MR element. The MR elements may be the conventional center-tapped, as shown in Fig. 1, noncenter-tapped, as shown in Fig. 2, or a shared terminal configuration, as shown in Fig. 3.

In Fig. 1, a pulse bias generator 1 directs pulses to a center-tapped MR element 2 to bias the element into its magnetic operating position. The outputs of the MR element 2 are directed to sample and hold circuits 3 and 4 for sensing the readback signal. The outputs of the sample and hold circuits are directed to an amplifying circuit 5 for amplification of the signal to a utilization circuit. Different MR element configurations are shown in Figs. 2 and 3, but the results, as shown in Fig. 4, are the same.

Fig. 4 illustrates a readback signal at one terminal leg from an MR element. The solid line represents the head signal with DC bias. The dashed lines show the signal with a pulse bias taken before the sample and hold circuit. The dotted line is the output of the pulse bias with sample and hold taken at the output of the sample and hold circuit. In the case of AC or pulse bias without a sample and hold circuit, the resultant amplitude of the filtered readback signal is proportional ...