Moderators: Dave Moll, Andrew Davie, Steve Anderson
Steve Anderson wrote:May I suggest a somewhat simpler method? A dual monostable and a gate will do this. It could be a 4538, 221 or a dual 555 (the 556). The first of the pair detects the missing pulse as per usual, the second upon missing pulse detection simply gates out as many sync pulses as you desire. There are constraints on timing, but none that critical at all.
If there's interest I'll do a fag-packet sketch tomorrow...it's the end of my day here...
Steve Anderson wrote:But what I'm still puzzled about is why should this be required? It's confounding me!...and my rubber chicken who's remained unusually silent...
Steve A.
gary wrote:To be honest, I seem to have lost track of what the aim of this exercise...
gary wrote:Well, no doubt, as in most control systems, the exact relationships are quite complicated, however in this case I can't quite understand why circuitry for gating out multiple sync pulses is required.
gary wrote: Firstly, are we talking about improving speed locking (line locking) or angular locking (frame locking)? I can't see how removing some extra pulses could improve the former, and whilst the prevailing explanation of how the standard missing pulse results in frame locking minus one line is plausible, I can't see how that is improved by removing extra pulses as that, assuming the same mechanism as for the single missing pulse, would give frame locking minus - n. I suppose any *deterministic* error could subsequently be adjusted out, but I am not sure that is what in fact is being attempted.
gary wrote:Secondly, why are pulses being extracted at all? Surely that, as in a standard missing synch pulse, is done at the source for a monitor, and compared against those generated by a typical encoder attached to the shaft of the monitor.
kareno wrote:Is Peter Smith on this forum? He's the man to ask!
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