Iron Horseman
Well-Known Member
That sounds a lot like some of the early command control systems such as CTC-16, which became one of the first "standards" for command control when it was published as a DIY in the 1979 Model Railroader magazine. The issue with all those earlier systems that had a base voltage with an additional "signal" pulses over the top, was that the signal could easily get lost in the noise of the base voltage. It was often hard to tell if the problem was a real problem or if the signal was just not punching through the base power. The magic of DCC is that the power IS the signal, so one knows if the unit is getting power it is also getting the signal.When I was in the Air Force, my roommate and I designed and built a 'DCC' system, 1973. No computers, just discrete DTL circuits, one rail 0V the other 12V, but capable of digital pulses. I don't remember all the details, but it only used 16 bits, the first one being the 'MASTER SYNC' on both rails. 8 of the pulses were the speed control, so only eight steps, through an op-amp to the motor.