External magnetic field generation apparatus capable of light intensity modulation and magnetic field modulation

An external magnetic field generation apparatus for use in a recording and reproduction apparatus which records information on a magneto-optical recording medium based on a magnetic field modulation system and a light modulation system, and said apparatus applying a magnetic field to a portion of the magneto-optical recording medium where the light beam is projected, comprising:

• first magnetic field generation means for generating an a.c. magnetic field which is reversed at a high speed, said first magnetic field generation means being used for the magnetic field modulation system;
• second magnetic field generation means for generating a strong d.c. magnetic field such that power consumption coincides with that of said first magnetic field generation means, said second magnetic field generation means being integral with said first magnetic field generation means, said second magnetic field generation means being used for the light modulation system;
• and
• power supply means for selecting one of said first magnetic field generation means and said second magnetic field generation means responsive to a switching signal, and for supplying power to said selected magnetic field generation means.