AVRCP

The Audio/Video Remote Control Profile is a Bluetooth profile that allows Bluetooth devices to control media playback on remote devices. It is typically used with A2DP devices for next/previous track selection and pause/play functions. Also known as: "Audio/Video Remote Control Profile"

AWS

AWS, which stands for Advanced Wireless Services, generally refers to the 1700/2100MHz frequency band pairing in the U.S. that will be used for T-Mobile USA's 3G UMTS network. Unlike typical spectrum licenses sold by the U.S. government, such as the 1900MHz PCS spectrum bands, the AWS bands use different frequency ranges for cell towers than they do for handsets. The U.S. government has indicated that it intends to offer other paired AWS bands in the future, but none are currently in use. Also known as: "Advanced Wireless Services"

Active Matrix

Active matrix LCD displays are known for their superior performance when compared with passive matrix LCD technologies. From the user's perspective, an active matrix display has higher contrast and better color saturation than do the cheaper passive matrix displays. Most active matrix LCDs are of the TFT type.

AMOLED

AMOLED, which stands for Active Matrix OLED, is a hybrid display technology that pairs the active matrix backplane from a traditional TFT display with an OLED display. As a result of their active matrix natures, AMOLED displays have faster pixel switching response times than do traditional OLED displays, which are prone to ghosting when displaying fast moving animations.

Aperture (f-number, f-stop)

The aperture of a lens system is the opening between the actual lens elements, typically made of glass or plastic, and the camera's digital sensor that translates the light into image data. Aperture openings are referred to in terms of stops or f-stops that equate to the ratio of the lens focal length to the diameter of the opening. A lens system with a focal length of 50mm and an aperture opening that is 25mm in diameter would equate to an f-stop of 2, and would be known as a 50mm f2 lens. Some lenses have variable apertures that can be set to one of multiple f-stop values. Reducing the aperture size decreases the amount of light that makes it to the sensor as well as increases the amount of depth of field that the lens will provide.

A-GPS (Assisted GPS)

Assisted GPS is a system commonly found in CDMA mobile phones in the US that offloads some of the processing requirements of a typical GPS receiver to a central server that can perform the calculations much more quickly. This allows the A-GPS receiver to work on devices with less computing resources than would be possible otherwise. A-GPS received a boost when the US government required mobile phones to support the E911 emergency calling system, which requires the callers location to be known.

Autofocus (AF)

Autofocus refers to a camera lens' ability to adjust its configuration in order to focus properly on a subject regardless of whether it is near or far from the camera. Autofocus lenses generally provide vastly superior image quality than do their fixed focus cousins since they do not have to rely on their depth of field.

AMPS (Advanced Mobile Phone System)

North America's AMPS and its variants used elsewhere in the world are the antiquated analog cellular phone networks used before the advent of digital technologies such as GSM and CDMA. AMPS was first used in North America in the early 1980s and is still used today, though mostly in rural areas.

A2DP

The Advanced Audio Distribution Profile is a Bluetooth profile that allows for the wireless transmission of stereo audio from an A2DP source (typically a phone or computer) to an A2DP receiver (a set of Bluetooth headphones or stereo system). Such devices typically also support the AVRCP profile as well in order to allow for track selection and such. A common misconception is that A2DP support is available on all Bluetooth 2.0 devices, which is not the case, and that A2DP is only available on Bluetooth 2.0 devices, which is also not true. A2DP support can exist in older versions of Bluetooth, it just was not commonly supported.