Viewmaster wrote:This is always assuming that .1 to .25 msec std. NBTV pulses can ever be recorded on a cylinder at all. Doubtful. Albert.

The analogy I would draw here is that of a mechanical low-pass filter, that is there is a finite limit to the frequencies that can be recorded. With a mechanical process there are other factors thrown into the equation, mechanical resonances, non-lineararity and a certain degree of noise.

So, as a starting point, follows are three plots of a 125µs sync pulse passed through three filters, one each at 20kHz, 10kHz and 5kHz. These were all four-pole Sallen and Key Butterworth filters, Bessel would be better, Chebychev worse from a pulse shape point of view.

Which flavour of filter approximates a mechanical one is something that I have no idea about!

As is quite apparent, even with a 20kHz bandwidth things are not so good, at 5kHz it is marginal at best!

How this translates into a mechanical system is over to others...

Steve A.