Re: Infra red remote control receiver
When I was playing with Grundig CTVs, the first ones with rem com used the TP7. Condenser L/S, a tapped coil giving 7 discrete frequencies.
There next model, the TP12had (I think) four frequencies, but these were chopped into pieces and mixed up so that a train of the four were sequenced. eg, ABCA -- ABCA repeated. (*) Anyway, this produced 12 commands. This was followed by the TP16, now however with infra red signals. These used the same coding and frequencies as the TP12, but with four more commands.
At the time, the cost of a TP12 was horrendous (£100+ i think) whereas the TP16 was around £30, with non OEM replacements about £15 max.
I bought these cheaper ones, cut the track to ensure only the first 12 programmes, removed the condenser microphone from the TV set, and tagged in an infra red diode and a couple of resistors. Now I could sell the sets and still make enough £££s to keep me happy.
(*) That explanation is probably way off, but I do have the books somewhere upstairs should I need to KNOW for certain.
Les
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