Oscilloscopes

[Cinderlane Productions]

Can I get away with using a 20 MHz oscilloscope to satisfactorily view
video waveforms?

I know that in order to trigger all the test signals properly, I should
use at least a 150 MHz unit -- preferably a conventional video waveform
monitor. However, I cannot afford one.

It is not my intention to measure rise times or verify parameters in a
professional capacity. Rather, I want to accomplish such simple things
as verifying that closed captioning is present in the correct vertical
interval line, determining that color burst and sync levels are "in the
ballpark," and checking for the presence of SCH frame-burst signals.

To reiterate, I will be using the scope too infrequently to justify a
major expenditure of funds, yet I want one with a bandwidth sufficient
enough to allow me to count the lines in the vertical interval and
identify what is in them.

 

[David L. Jones]

Can I get away with using a 20 MHz oscilloscope to satisfactorily view
video waveforms?

I know that in order to trigger all the test signals properly, I should
use at least a 150 MHz unit -- preferably a conventional video waveform
monitor. However, I cannot afford one.

It is not my intention to measure rise times or verify parameters in a
professional capacity. Rather, I want to accomplish such simple things
as verifying that closed captioning is present in the correct vertical
interval line, determining that color burst and sync levels are "in the
ballpark," and checking for the presence of SCH frame-burst signals.

To reiterate, I will be using the scope too infrequently to justify a
major expenditure of funds, yet I want one with a bandwidth sufficient
enough to allow me to count the lines in the vertical interval and
identify what is in them.

A lot of 20MHz scopes (probably the majority of modern design ones)
have a "TV" triggering mode.
Don't know how effective it is for counting lines etc though.

Dave

 

[Lewin A.R.W. Edwards]

Can I get away with using a 20 MHz oscilloscope to satisfactorily view

video waveforms?

A counter-question - What's your budget? A Tektronix 465 or something
in that ballpark should be findable on eBay for around $150 (at least,
I've sold two working units with probes in that price bracket during
the last year). More than adequate for what you want to do. Actually I
shouldn't have sold mine, but I got two new scopes and don't have the
room, though it does look cool to have four scopes stacked on top of
each other

If you're on a tight budget and looking at _new_ scopes, my advice is:
Don't. If you're not willing to pay much, you'll be buying some
no-name piece of equipment. Used name-brand hardware is a much better
investment.

BTW, you don't actually mention but I assume you're looking at regular
PAL/NTSC/SECAM