Electronic white board with multiple common-frequency pens

The invention discloses an electronic white board with multiple common-frequency pens. A main control card of the electronic white board identifies a plurality of electronic pens and an eraser by judging the serial numbers of the common-frequency electronic pens and the eraser at different times, each electronic pen and the eraser have respective fixed serial number and work at the same frequency, and when the pens are in use, the colors of the pens can be determined without additionally selecting shortcut keys. Time sharing operation is performed on the electronic pens and the eraser, and each piece of equipment only works within respective time and does not emit a signal at other time. The emitting frequency of the electronic pens is the same as that of the eraser, the working frequencies of the electronic pens and the eraser are generated through a single chip microcomputer clock, the main control card judges the work of the electronic pens and the eraser at different times, and the working periods of the electronic pens and the eraser are synchronized through a reference signal transmitted by the main control card, so that the coordination of the work of the electronic pens and the work of the eraser is guaranteed. By the adoption of the electronic white board with multiple common-frequency pens, the requirement that a user can use over two electronic pens at the same time to write in different colors at the same time can be met.