Digital Migration Process
The Go DIGITAL South Africa is a catch phrase for digital migration processing South Africa. As you may well know, the Television has been in South Africa from 1976. When it started, it was black and white, then evolved to colour television. Due to apartheid, white people owned televisions more than any race in the country. After 1994, the country put in place legislation that ensured broadcasting services that reflected/ represented all South Africans despite of their race or economical status.
Today, 11 million households in South Africa own televisions with programmes in their own languages. The government continues to ensure universal service and access by providing broadcasting services through digital migration process that promises to enhance diversity and access especially for the previously marginalised.
The Benefits of Digital Migration or DTT:
- The digital migration process promises more channels, i.e. more programmes like: sports, children, parliamentary, entertainment, music and more vernacular channels which means variety of choice to viewers.
- Every citizen irrespective of geographical location, race, and economical status will enjoy access of all free-to-air channels of good quality picture and sound.
- On screen Electronic Programming Guide and program synopsis.
- Parental guidance and control of programs
- Disability services for hard of hearing and sight.
What is Digital Migration?
The digital migration can be defined by two concepts: the switch or migration from analogue and digital signals.
Prior to the 1990s, broadcasting transmitted sound and video through airwaves by analogue signals.
As much as this method worked well, unfortunately it needed a lot of space on the frequency spectrum. Both television and radio are allocated valuable spectrum in each band. This means a different and unique frequency is allocated for each radio and TV service. Clearly a very spectrum inefficient method of delivering multi channels services.
TV or radio channels are allocated frequencies depending on the geographical location.
- For example in radio: Metro FM is a national radio, in Gauteng province it is accessed on FM 92.4 which is a radio frequency. Whereas in Durban, Cape Town, and/or any other place in the country, the same radio station is accessed on a different frequency. Effectively that suggests that there is a waste of frequency spectrum.
- The same goes for TV channels, they are each allocated a unique frequency allocation per area. Unfortunately to some, this means limited access of broadcasting channels and lack of variety of choice that is enjoyed by others, due to lack or spectrum congestion.
- The quality of your TV picture is dependent on the positioning of an antenna and how far you is from a local transmitter site.
- In the analogue signal transmission method you can only have 1 radio or TV service per channel and 1 unique frequency. TV transmission, be it analogue or digital uses the UHF (Ultra High Frequency) and VHF (Very High Frequency) bands.
Digital: Post 1990s, the new dawn of digital broadcasting, where sound, video, text and still images can be transmitted in the form of binary digits i.e. ones and zeros. This technology allows for information to be compressed thus saving radio spectrum. Digital Terrestrial TV (DTT) is like Digital satellite, but DTT uses ground based (terrestrial) digital transmitters to distribute the signals to your home.
Due to the benefits of digital transmissions, soon to be launched in South Africa, we all benefit.
- For each unique frequency in analogue – or 1 TV service we now with digital in the same spectrum, can transmit 15 standard definition TV services.
- Digital is highly spectrum efficient. In the same geographical area, all TV transmitters can operate on the same frequency without interference.
- Clearly, after analogue switch-off a huge portion of valuable spectrum will be released back to ICASA, which is the ICT sector regulator.
- The home user will require a simple decoder that converts the digital signal to analogue for their TV set. NO new TV set is required.
- After digital migration is completed, the spare spectrum can be reused for other services of national interest.
Having explained the two concepts (analogue and digital) above, digital migration is a process of moving from the analogue to the digital broadcasting for TV and radio. South Africa will only start with television and only later will consider digital radio.
TV programs can be distributed to the home user by terrestrial, satellite and cable transmissions. In SA we use digital satellite and soon digital terrestrial. Cable delivery is now via Internet Protocol (IP TV–internet) but this is very limited due to bandwidth access and constraints currently.
Definition of Terrestrial and Satellite TV:
- Terrestrial television uses a network of transmission towers to relay the signal across the country. Each transmission tower has a specific area of coverage, and it is the network of coverage that provides television signals across the country. If you are within an area covered by a tower, then you will be able to receive broadcast services from that tower.
- Satellite television broadcasting uses a satellite which is in orbit above the earth. The broadcasting signals are sent to the satellite and viewers receive the signal via a satellite dish.