what does the satellite tv signal comprise of and how does encryption work for millions of receivers?
I have read the signal has compressed and encrypted channels, but wondering if they come down as 1 digital stream, or at diff. frequencies? Does the receiver have to decrypt from 1 stream of bits, and how does the provider encrypt signals for millions of receivers in a particular area..interested in knowing their algorithms/concepts at a higher level.
Tagged with: digital stream • receivers • signals
Filed under: Online Satellite Tv
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This is a pretty huge question to be answered here. I'll try to hit the high points.
Yes, there are multiple frequencies. Each satellite has channels that are a finite size and can carry a finite amount of data. So, to add capacity, they must use multiple channels. When a satellite is full, they start on another satellite.
Within each transponder (channel) there is one data steam with multiple services (programs or sub channels). These are usually DVB signals so you can look that up for all the detailed information.
As far as encryption goes, each receiver will have it's own unique name. A data table in the stream will contain the authorization codes for a particular receiver. That's how they can turn specific receiver on or off for a particular service.
The encryption algorithms are not common knowledge as are the codes.