Hi,
It has been a long time logging into this forum but couldn't resist myself to answer this thread. First about the $$money$$ part.
People in this forum do actually help each other out and the n number of posts prove that. This is the most popular and helpful place on the www as far as PBP is concerned.Pros and gurus here do help for free which have cost them n number of hours learning and working out.So my earnest request is that please try to avoid
What sayzer meant was perhaps that it would be better to help somebody on a actual project that enriches this forum. Rather than the forum being treated as a answer machine. It feels good when you are part of somebody's hardwork but equally depressing when you find that only you were serious the other member was not. And sayzer was kidding....perhaps. Look into the posts of sayzer and you will find the answers about his contribution. I myself have been helped greatly by this forum. All for free...! Without the active guys on this forum I might have not acomplished success in many of my projects. Okay enough blah.. blah... now the technical stuff.i just don't get the idea why you guys keep on asking for money..
For an addressable system to work successfully you need to ensure that the signalling from your cable tv head-end does reach the last distribution amplifier. If you try to use the unused RF bandwidth you would end up modulating/demodulating your signals in the RF region and probably the cost factor would not be justified. So my recommendations are use the power line (mostly low voltage ac in the range of 40 to 80 volts) as your carrier and transmit your signals over it. (Sniff X10 on the net. PBP supports it) This would reduce the cost implementation of the signal mod/demod. Now if you could read the signal in your tiny little boxes to individual subscriber then you can take actions like block/unblock. RF relays are costly PIN diodes are not. To keep the scheme simple broadcast a packet from your headend that contains the inividual block/unblock commands. To make it even more reliable use a return to zero scheme that supports clock recovery at the PIC end. 5 consecutive block commands for example initiates a blocks and the same goes true for the unblock. This would ensure that erroneous decoding does not block customers who should not be.
Whew! That was pretty long. I hope the information is useful
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