V-ramp with hole

Category: Unknown · Tags: — · Posts: 6

#1 — dni_br · 2019-01-13

Doing vector scan with tektronix 465b.

Patching H ramp in x, V ramp in y, camera luma in z.

Problem : there s “hole” in V ramp

i ve change cable, invert the x and y. always the same pb.

i ve checked the v ramp on the oscilloscope. there s hole

on the crt it looks normal

i m lost… thks for help

denis

#3 — pbalj · 2019-01-13

That’s either a problem with the z signal, or theres a nonlinearity in the ramp. Put your score in to normal mode and view just the ramp in the scope. If it’s just a normal ramp it’s something up with z. Does the blank area scroll or is it stable

#4 — pbalj · 2019-01-13

You can’t have a hole in an oscilloscope trace, but it can move very quickly from one value to another, like a square wave, although hard to see its still a solid line. So if there appears to be a hole is withe because the signal jumps very quickly from one value to another or because the z is going down to a low value at that part

#5 — dni_br · 2019-01-14

hello,

it s not comming from the z input. on the second pictures i ve plugged only the y input.

Yes it s scrolling, slowly but it s scrolling

#6 — pbalj · 2019-01-15

Ok, can you take a picture of just the y signal in a normal scope mode, not xy mode? That will help show how the signal is distorting

#7 — dni_br · 2019-01-15

ok. i will this week end. thx