| 摘要 |
A magnetic reading head having a magneto-resistive element of the type in which the measuring current is forced to flow through the element at an angle with the easy axis of magnetization. For suppressing thermal noise (resistance variations under the influence of temperature fluctuations as a result of the contact of the element with a moving record carrier), the element is subjected to an auxiliary field parallel to the easy axis of magnetization, the direction of which is reversed at a frequency fs. The measuring current alternates at the same frequency in phase with the reversals of the auxiliary field. The output signal of the element is applied through a low-pass filter which cuts off signals of a frequency fs to a detection device.
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