farrellaa rrinker They even out from rail A to rail B because each half is identical, but with half wave lighting you are taking a reference from the center of the waveform to one side. It may not be much, but if say nothing but preamble packets were being sent, 0 bits have a longer effective 'on' time than 1 bits. The effective 'area under the curve' is greater for a string of 0 bits than for a string of 1 bits (possibly - if the exact pulse widths are just right, it could be that they are equal, it just takes more 1 bits per a given time slice. The DCC frequency is not constant, the 1 bits have a shorter wavelength and higher frequency, but if in a 100ms time sample, you have enough 1 bits, the mean voltage could be the same as that from the fewer 0 bits that would fit in that same time slice). I knew there was a reason I wanted to get a scope. This is getting rather esoteric and of not interest and of no real use to the average modeler. I agree it's going to be unnoticeable unless something is very wrong with your DCC system, or you actually do have zero stretching in use. I do think however that a string of say 5 zero bits will have a higher mean voltage (common to rail, not rail to rail) than a string of say 20 one bits that fits in the same time. More math is needed to compare the typical zero duration with the typical one duration. --Randy Randy, Could you explain this in English! LOL!
rrinker They even out from rail A to rail B because each half is identical, but with half wave lighting you are taking a reference from the center of the waveform to one side. It may not be much, but if say nothing but preamble packets were being sent, 0 bits have a longer effective 'on' time than 1 bits. The effective 'area under the curve' is greater for a string of 0 bits than for a string of 1 bits (possibly - if the exact pulse widths are just right, it could be that they are equal, it just takes more 1 bits per a given time slice. The DCC frequency is not constant, the 1 bits have a shorter wavelength and higher frequency, but if in a 100ms time sample, you have enough 1 bits, the mean voltage could be the same as that from the fewer 0 bits that would fit in that same time slice). I knew there was a reason I wanted to get a scope. This is getting rather esoteric and of not interest and of no real use to the average modeler. I agree it's going to be unnoticeable unless something is very wrong with your DCC system, or you actually do have zero stretching in use. I do think however that a string of say 5 zero bits will have a higher mean voltage (common to rail, not rail to rail) than a string of say 20 one bits that fits in the same time. More math is needed to compare the typical zero duration with the typical one duration. --Randy
Randy,
Could you explain this in English! LOL!
Rich
Alton Junction
richhotrainHow about now, Bob, after these most recent four posts? Rich
Don't get me wrong, I admire these guys with the electrical know-how to figure circuits out, and understand why they work the way they do. Kudo's to all of you.
-Bob
Life is what happens while you are making other plans!