Technology

Technology

Saturday, 14 March 2015

Smart Phone Gyaan

Screen

There are two factors when talking about displays. One is the kind of display technology used and the other is the kind of touch technology overlaying it. Although there is great hoopla about AMOLED displays in the market right now, a large section of phones still utilise LCD (Liquid Crystal Display) technology. Within the LCD space the most commonly found are TFT(Thin-film-transistor) displays. TFTs don't have great viewing angles, have poor visibility in direct sunlight and consume relatively more power. The other type is IPS (in-plane switching ) technology found in a few rare phones such as iPhone 4 and Droid X. Apple calls it 'retina' technology, which is merely marketing gimmickry. However IPS dissplays look brilliant (Viewing angles at all) thanks to their crystal molecules being oriented such that their motion is parallel to the panel rather than perpendicular. AMOLED(Active- matrix organic light emitting diode) displays are all the hype lately thanks to Samsung and HTC plonking them in phones such as Omnia 2 and Legend. In these displays organic compounds form the electroluminescent material making them quite vibrant and with great contrast. Super-AMOLEDs (found in Samsung Wave and Galaxy S) take things a step further to improve clarity by placing the touch sensors on the displays itself rather than a separate layer. This makes it wafer thin and improves viewing angles. Speaking of touchscreens there are two types- resistive and capacitive. Resistive, the more primitive technology, works by placing two layers of conductive material close to each other. When a finger or stylus depresses the layer on top, it makes a contact with the other layer forming a circuit at that location. Capacitive is the more advanced technology and is now increasingly being  used. For these screens the glass (an insulator) is coated with a transparent conductor such as indium tin oxide. When a finger touches the screen it breaks the electrostatic field. It's position is then measured relative to the four corners of the screen by the processor.



Microphone

Smartphone microphones depend on chipset circuitry and processing to clear out the vocal signal. It can be termed as noise suppression or cancellation depending on the technology used. Cutting edge Smartphones (iPhone 4 and Droid X for eg) use two microphones for cancelling out noise. The second one is placed far from the voice mic. It detects the Signature of ambient noise and suppresses it.



Camera
Smart phone cameras depend a lot on image processing rather than just the hardware when it comes to image quality. This is because no matter how large the camera resolution gets in Megapixels(MP), but the sensor size remains small you will have bad imaging. The sensor is what converts the optical image into electrical signal. What matters also is the autofocusing capability, shutter speed control etc.


Battery

Most smartphones these days come with Li-on (lithium-ion) batteries. In the cell, Lithium ions move from the negative electrode to the positive electrode producing the current. These are re-chargeable but have a fixed number of life-cycles. The capacity is measured in milliampere-hours (mAh). Phones with 1500 mAh battery rating will usually last long enough.




Processor

The processor is the heart or rather the brain of your smartphone, essentially what makes a smartphone smart. It does all the processing involved, be it when you run an application or even calculation to translate the position of your finger on the touch screen. Current high end smartphone processor are clocked at 1GHz. Samsung, Qualcomm and texas Instruments make these processors and are battling it out. Much like the desktop space, which is populated by names like Phenom, Core i and Athlon Processors in the mobile space too at times acquire brand names. Samsung has Humming-bird, and Apple A4 while Qualcomm calls them Snapdragon, Scorpion etc, and Texas Instruments, OMAP. These chips are all based on processor cores from ARM, a company doesn't manufacture chips but rather only designs the cores for such application processors. Some of ARM's designs include older generation cores such as the ARM9, ARM11 and the relatively recent Cortex-A8 and Cortex-A9, Manufacturers make their own chipsets(System on Chip design) often combining a GPU, cellular modem, and GPS on board. The QSD8250 chipset featured here for instance, used the Adreno 200 graphics solution and a Cortex-A8 core, together called Snap-dragon by Qualcomm.



Ram

Memory in cellphones functions pretty much the same way it does in a desktop PC. The more the RAM, the more applications you can keep open, the more you can multitask, Low to mid range phones have RAM in the vicinity of 256MB, while high end phones such as the Desire HD have 768MB.


Removable Storage


Removable storage for smartphones comes comes in the form of SD (secure digital) cards. Depending on size there are variants such as MicroSD(Most common) and MiniSD. Phones can only support upto a certain amount of memory, with smarthpones it usually 32GB. There are speed classes in SD cards specified by the SD association. Class 2 for example supports H.264 video recording, MPEG-4, and MPEG-2 video recording.


G-sensor

Smartphones sense their relative position or orientation by way of either an Accelerometer or Gyroscope. Most phones have Acceleometers to help keep track or orientation i.e. if you turn the phone it will ensure change from landscape to portrait and vice versa. This is done by analysing the vector acceleration which is caused as a result of weitght (essentially g-force) experienced by a test mass inside the accelerometer device. Some high end smartphones such as iPhone 4G come with a Gyroscope which is capable of registering movement in a 3D space. So for instance it can detect the motion when you move the phone towards or away from your body. It only has applications in gaming as of now.



source :- Digit Magzine


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