The simple ON/OFF keystroke on green laser pointer

Magnetoresistance effect: some magnetic material placed in the magnetic field, the magnetoresistance effect: magnetic material on the magnetic field through a constant current when the magnetic field changes, the fruit through a constant current when the magnetic field changes, the resistivity of the material also will change, this is the magnetoresistance effect. also change with the resistivity, magnetoresistance effect. MR heads is to use the magneto-resistance effect to read out the signal heads using magneto-resistance effect to read out the signal. The simple ON/OFF keystroke brings green laser pointer users practicability.MR heads is to use the magneto-resistance effect to read out the signal 18 computer composed of the principle of MR head model MR head model of Computer Science 19 computer composition principle 8.2.3 by magnetic recording on magnetic recording is an encoding method of magnetic recording method is a coding method, is in accordance with a regulation in the form of a coded square law will transform a series of binary digital information storage medium corresponding magnetization reversal of the magnetosphere in the form of the corresponding magnetization reversal, and read and write control circuit to achieve this conversion law. conversion law. of Computer Science, several magnetic recording several common magnetic recording 20 computer Principle The simple ON/OFF keystroke brings green laser pointer users convenience.8.2.3 Magnetic Recording method (1) return to zero (RZ) return to zero (RZ) of Computer Science, write to the head coil into a pulse current in the string, write to the head coil into a series of pulsed current, positive pulse '1 ', the negative pulse '0', so that the magnetosphere in the record '1 ', the negative pulse', so that saturation magnetization state of the magnetosphere never magnetization state in the record ', the transition to a particular direction, never magnetization state of the transition to a direction of saturation magnetization state in the record' never magnetization state changes into another direction full saturation magnetization state of the magnetic state of the record '0 'never change to another direction. between the two bits of information, and the magnetization state between the two information, the coil current is zero 22 computer component principle 8.2.3 magnetic recording means (2) does not return to zero (NRZ) does not return to zero (NRZ) School of Computer Science in the log information in the record information, The simple ON/OFF keystroke brings green laser pointer users portability.the head coil, if there is no forward current shall be the direction of current no current is not zero there must be the direction of current, no current state system. magnetosphere is not positive saturation magnetization and is the reverse saturation magnetic sequential write 'or of consecutive Write '1 'or '0', the direction of the write current is time-invariant, therefore, the same, so this record than zero the system reduces the number of magnetization reversal of the number of flip 23 Principles of Computer Organization 8.2.3 Magnetic Recording way to turn the non-return to zero ((3) See "1" to turn non-return to zero (NRZ1) on the turn of the non-return-to-zero system NRZ1) School of Computer Science and of no return zero system, recording information, and do not return to zero, record information, there is always a current through the head coil. difference is that there is a current difference is that the current flowing through the head only in the record ' change the direction of change in the direction of the change in record '1 'direction,Users may turn on and off the green laser led at any time. the magnetosphere magnetization direction to flip the record' when the current direction unchanged; record '0 ', the current direction is the same, magnetosphere to maintain the original magnetization direction of magnetization direction 24 Principles of Computer Organization 8.2.3 magnetic recording method (4) of Computer Science of the phase modulation (PM) phase modulation of the system (PM) 25 phase modulation system, also known as phase encoding (PE).