iPod Technology

1. iPod Technology Why Won’t My iPod Work?

2. What is an iPod? • 60 GB Portable Media Center • Holds Movies, Songs and Pictures in MP3 format • Variations of the iPod include: • iPod Shuffle- 512MB or 1 GB audio storage • iPod nano- 1, 2, 4 GB digital audio and photo storage • iPod Mini- 4, 6 GB audio storage www.apple.com

3. Types of iPods Nano iPod Video Mini Shuffle www.apple.com

4. MP3 Players • Transfer data from a computer using the computers USB port, FireWire port or parallel port. • Information is then saved using either solid state memory or onto a hard drive: • Internal Flash Memory Solid state memory devices are favored because they do not contain any moving parts in the memory encoding and are electronically powered. -semiconductors made of thin films www.computerhope.com/jargon/s/solimemo.htm

5. Flash Memory • Uses ROM (Read-only Memory) • Integrated circuit programmed with specific data • Non-volatile-memory isn’t lost when power is removed • Used as a back-up storage device for computers • Data storage is unchangeable or requires a special operation to change http://electronics.howstuffworks.com/mp3.htm

6. iPod Shuffle and iPod Nano Uses a EEPROM Flash Memory -Lighter -Stores fewer songs -Long lasting batteries -Solid state memory EEPROMs -Electrically erasable programmable read-only memory -Data is written or erased one byte at a time -In other flash memories, data must be written or erased in one block at a time http://electronics.howstuffworks.com/ipod7.htm www.apple.com

7. There are two transistors separated by thin oxide layer - n-type Metal-Oxide Semiconductor Field Effect Transistor (n-MOSFET) Changes in the position of the gate caused by the increase or decrease in voltage programs the cell value. Information is encoded by the combination of 1 and 0. How EEPROM Works

8. When a charge is applied, the electrons in the N-type are pulled into the p-type through the boundary of the junction to form a negative ion with the holes. Filling a hole makes a negative ion and leaves behind a positive ion on the n-side. This build up of charge creates a depletion region which inhibits electron transfer unless a forward bias is applied. A forward bias is an applied voltage in the forward direction, assisting electrons to overcome the barrier of the space charge in the depletion region. www.interq.or.jp/japan/se-inoue/e_ckt30_6.htm Review of P-N Junction http://hyperphysics.phy-astr.gsu.edu/Hbase/solids/pnjun.html

9. When voltage is not applied to the gate, there is no current flow between the drain and then source. The cell is then in the 1 position. When a positive voltage is applied to the gate of the N channel. The electrons of the source and drain are then attracted to the gate and go into the P channel semiconductor. The movement of electrons acts like a bridge for electrons to move from the drain into the source. This movement of the bridge caused the cell to be in the 0 position. n-MOS FET www.interq.or.jp/japan/se-inoue/e_ckt30_6.htm

10. Use hard drive as memory system.This uses perpendicular magnetic recording. Benefits: Low level of recording noise. Able to store 10 times as much information as a flash drive. iPod Mini and iPod Video http://www.amazon.com/gp/product/B0001A99LK/ref=dp_variations_3/102-5619421-0964114?%5Fencoding=UTF8 http://electronics.howstuffworks.com/ipod7.htm

11. Perpendicular Magnetic Recording -Multi-layered magnetic film composed of ferromagnetic metal layers of Co alloy containing Cr and non-magnetic metal layers of Pd alloy. This layer makes up the platter. -The layered structure reduces the magnetic exchange interaction between magnetic particles and allows the moment to remain the same direction. Hard drives store information by changing the polarization of microscopic magnetic bits aligned end-to-end on a platter www.komag.com/technology/perpendicular_pmr.html www.popsci.com/popsci/bown2005/computing

13. Microprocessor monitors all user input through playback controls, displays information about the current song and sends directions to the DSP (digital signal processor) chip about how to process the audio. DSP pulls data from the memory, amplifies effects and sends it to the amplifier. Runs a decompression algorithm that encodes the compression of the original MP3 file. The amplifier sends the electrical signal to the speakers via a cord. http://electronics.howstuffworks.com/mp3-player2.htm

15. Receives messages from the amplifier and re-interprets it into physical vibrations. The driver produces sound waves by rapidly vibrating a flexible piece of paper, metal or plastic called a cone or diaphragm. To cause the cone to move, a voice coil is attached to the bottom. The coil acts as an electromagnet. The electromagnet consists of a with a piece of magnetic metal with iron wrapped around it. A current is sent through the wire creating a magnetic field with the iron. Unlike a permanent magnet, the poles can be switched. This switching of electric flow is characteristic of a stereo signal. Earbuds http://howstuffworks.com/speakers.htm

16. Inside the speaker there is also a permanent magnet. The electromagnet and the permanent magnets are attracted to each other depending on the current flow in the electromagnet. When the orientation of the current switches so does the direction of the repulsion and attraction. The alternating current constantly reverses the magnetic forces between the voice coil and the permanent magnet. This pushes the coil back and forth rapidly. Earbuds Continued… http://howstuffworks.com/speakers.htm

17. www.apple.com Sources http://howstuffworks.com/speakers.htm www.computerhope.com/jargon/s/solimemo.htm www.interq.or.jp/japan/se-inoue/e_ckt30_6.htm http://electronics.howstuffworks.com/mp3-player.htm http://electronics.howstuffworks.com/ipod7.htm http://www.amazon.com/gp/product/B0001A99LK/ref=dp_variations_3/102-5619421-0964114?%5Fencoding=UTF8 www.komag.com/technology/perpendicular_pmr.html www.popsci.com/popsci/bown2005/computing http://hyperphysics.phy-astr.gsu.edu/Hbase/solids/pnjun.html