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CCIR System I
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CCIR System I
CCIR System I is an analogue broadcast television system. It was first used in Ireland starting in December 1961 as the 625-line broadcasting standard to be used on VHF Band I and Band III, sharing Band III with 405-line System A signals radiated in the north and east of the country. Ireland slowly extended its use of System I onto the UHF bands.
The UK started its own 625-line television service in 1964 also using System I, but on UHF only – the UK has never used VHF for 625-line television except for some cable relay distribution systems.
Since then, System I has been adopted for use by Hong Kong, Macau, the Falkland Islands, South Africa, Angola, Botswana, Lesotho, Namibia, Tanzania, Saint Helena, and Pitcairn Islands.
As of late 2012, analogue television is no longer transmitted in either the UK or Ireland. South Africa is still broadcasting in System I, but have plans to end the service at any time.
Some of the important specs are listed below:
A frame is the total picture. The frame rate is the number of pictures displayed in one second. But each frame is actually scanned twice interleaving odd and even lines. Each scan is known as a field (odd and even fields.) So field rate is twice the frame rate. In each frame there are 625 lines (or 312.5 lines in a field.) So line rate (line frequency) is 625 times the frame frequency or 625×25=15625 Hz.
The total RF bandwidth of System I (as originally designed with its single FM audio subcarrier) was about 7.4 MHz, allowing System I signals to be transmitted in 8.0 MHz wide channels with an ample 600 kHz guard zone between channels.
In specs, sometimes, other parameters such as vestigial sideband characteristics and gamma of display device are also given.
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CCIR System I AI simulator
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CCIR System I
CCIR System I is an analogue broadcast television system. It was first used in Ireland starting in December 1961 as the 625-line broadcasting standard to be used on VHF Band I and Band III, sharing Band III with 405-line System A signals radiated in the north and east of the country. Ireland slowly extended its use of System I onto the UHF bands.
The UK started its own 625-line television service in 1964 also using System I, but on UHF only – the UK has never used VHF for 625-line television except for some cable relay distribution systems.
Since then, System I has been adopted for use by Hong Kong, Macau, the Falkland Islands, South Africa, Angola, Botswana, Lesotho, Namibia, Tanzania, Saint Helena, and Pitcairn Islands.
As of late 2012, analogue television is no longer transmitted in either the UK or Ireland. South Africa is still broadcasting in System I, but have plans to end the service at any time.
Some of the important specs are listed below:
A frame is the total picture. The frame rate is the number of pictures displayed in one second. But each frame is actually scanned twice interleaving odd and even lines. Each scan is known as a field (odd and even fields.) So field rate is twice the frame rate. In each frame there are 625 lines (or 312.5 lines in a field.) So line rate (line frequency) is 625 times the frame frequency or 625×25=15625 Hz.
The total RF bandwidth of System I (as originally designed with its single FM audio subcarrier) was about 7.4 MHz, allowing System I signals to be transmitted in 8.0 MHz wide channels with an ample 600 kHz guard zone between channels.
In specs, sometimes, other parameters such as vestigial sideband characteristics and gamma of display device are also given.
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