Difference between revisions of "Sega Channel"
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The Sega Channel was a service offered by Sega between December 1994 to mid 1998. It the user to download various games, which changed on a monthly basis. | The Sega Channel was a service offered by Sega between December 1994 to mid 1998. It the user to download various games, which changed on a monthly basis. | ||
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| + | ==Technical information== | ||
| + | The Sega Channel signal originated in Denver, CO. It was carried over the Galaxy 7 satellite, located 91.0 degrees W longitude using transponder 1 with horizontal polarisation. The uplink signal was at a carrier frequency of 1.435 GHz and occupied 8 MHz bandwidth using QPSK modulation. The downlink signal was at a frequency of 1.1 GHz and occupied 6 MHz bandwidth using QPSK. | ||
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| + | Subscriber Loop | ||
| + | * occupied two 3 MHz non-contiguous channels | ||
| + | * data rate was 6 Mbit/s | ||
| + | * tunable to 68 different operating frequencies between 51 and 118 MHz | ||
| + | * Bit error ratio was <10E-06 | ||
| + | * used Quadrature Partial Response (QPR) modulation | ||
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| + | QPR is a modulation scheme that uses a controlled inter-symbol interference. The receiver is capable of logically decoding the signal. QPR provides 20% better bandwidth performance than QPSK with only a minor increase in signal power. This Sega Channel adapter allowed the customer to download the game selected in less than 1 minute. The adapter contained 4 MB [[DRAM|DRAM,]] which held a game of up to 32 megabits (or 4 megabytes) in size. Once the game was downloaded, it worked exactly as if it were a cartridge. Sega also had ratings for each game and supplied the parents with a password (4 digit pin number) if so desired. | ||
Revision as of 18:04, 18 August 2012
The Sega Channel was a service offered by Sega between December 1994 to mid 1998. It the user to download various games, which changed on a monthly basis.
Technical information
The Sega Channel signal originated in Denver, CO. It was carried over the Galaxy 7 satellite, located 91.0 degrees W longitude using transponder 1 with horizontal polarisation. The uplink signal was at a carrier frequency of 1.435 GHz and occupied 8 MHz bandwidth using QPSK modulation. The downlink signal was at a frequency of 1.1 GHz and occupied 6 MHz bandwidth using QPSK.
Subscriber Loop
- occupied two 3 MHz non-contiguous channels
- data rate was 6 Mbit/s
- tunable to 68 different operating frequencies between 51 and 118 MHz
- Bit error ratio was <10E-06
- used Quadrature Partial Response (QPR) modulation
QPR is a modulation scheme that uses a controlled inter-symbol interference. The receiver is capable of logically decoding the signal. QPR provides 20% better bandwidth performance than QPSK with only a minor increase in signal power. This Sega Channel adapter allowed the customer to download the game selected in less than 1 minute. The adapter contained 4 MB DRAM, which held a game of up to 32 megabits (or 4 megabytes) in size. Once the game was downloaded, it worked exactly as if it were a cartridge. Sega also had ratings for each game and supplied the parents with a password (4 digit pin number) if so desired.
