How an ATSC Tuner Works

An ATSC tuner works by generating audio and video signals that are picked up from over-the-air TV broadcasts. ATSC tuners provide the following functions: demodulation, transport stream demultiplexing, decompression, error correction, analog-to-digital conversion, AV synchronization and media reformatting to fit the specific type of TV screen optimally.

Demodulation

Demodulation means that the signal that is pulled off the airways is transformed into a usable signal that a TV set can use to produce quality images and sound.

Transport Stream Demultiplexing

In the US, multiple digital signals are combined and then transmitted from one antenna source to create over the air broadcasts. An ATSC receiver then is able to decode the transport stream and display it on a TV set.

Decompression

Since digital signals that are broadcast over the air are compressed (packed smaller), once they are received by the ATSC tuner, these compressed packets of digital data are then unpacked to their original size, or using the proper term, decompressed.

Error Correction

Error correction is a technology that is used by the ATSC tuner to make sure that any data that is missing can be corrected. For instance, sometimes interference or a poor-quality signal will cause the loss of data information that the ATSC tuner receives. With error correction, the tuner has the ability to perform a number of checks and repair data so that a signal can be viewed on a TV set.

AV Synchronization

AV synchronization is the coordination of audio and video signals being displayed on a digital TV in proper time. AV synchronization ensures that the audio does not lag behind the video that is being displayed on the TV set or vice versa, so that both audio and video are in sync.

Media Reformatting

Media reformatting is extremely important because the formatting of images on TV sets differs significantly according to the technology employed. For instance, some televisions have an interlaced picture, whereas others have a progressive-scan picture.

Different televisions have a different aspect ratio.