| 摘要 |
PURPOSE:To obtain a reproduction output having a high level and high S/N even to a magnetic record signal of ultra-high density by making use of a change of the coupling degree of a high frequency coupling circuit which varies its coupling degree by the change of the high frequency characteristics of a magnetic material due to a signal magnetic field generated from a magnetic recording medium. CONSTITUTION:A magnetic recording medium 1 contains a record layer 3 and a magnetic film 4 formed on the layer 3 with high frequency characteristics varying with a signal magnetic field which is magnetically recorded to the layer 3. A reproduction head 5 forms a coaxial resonator which defines the thickness direction of the medium 1 as a resonance current path with an external conductor 6, a needle-shaped electrode 7 and a conductor 11. Then a high frequency coupling circuit which uses the film 4 as a coupling element is formed with an input coupling coil 13, a coaxial resonator and the 2nd coupling coil 15. The head 5 is driven relatively to the medium 1, and at the same time the high frequency energy is injected to the high frequency coupling circuit via the coil 13. Thus the electromagnetic coupling degree of the high frequency coupling circuit varies, and the high frequency output voltage emergiing at the output of the coaxial resonator received modulation corresponding to the signal magnetic field. This modulation is detected to obtain a reproduction output 23. |
