Measuring VIDEO signals with a oscilloscope?

Ya it does look ilke that but without the color burst and sync pulse

THe waveforms RGB and composite does loook like that

Isn't that waveform a MODULATED or encoded waveform? because its very hazy looking

If you take that same hazy waveform and turn the "times per divsion" on the oscilloscope down it will make the video waveform into dots,square,vertical lines cause its some type of encoding or modulated but what am i trying to say you think? that i am seeing ?

It look likes little bits of pieces when you move the times per division know it breaks up the encoded waveform

But on my oscillscope i see a video hazy waveform like what you have, but NO colour burst or sync like that at all, its either a straight horizontal line of small dots or just a small line about 1/4 inch every other cycle under neath the hazy video waveform

Added after 9 minutes:

How do i sync my oscilloscope up to the vertical sync pulse of the video input?

How do i sync my oscillscope up to the horizonatal sync pulse of the video input?

For my composite video signal and RGB i don't get any color burst or sync pulse like that at all its just nothing just the hazy blurry waveform like what you have

What kind of waveform is that? a encoded? interlaced? modulated?

The oscilloscope display looks hazy because it has 525 lines superimposed together. Each line is different. It would look clearer if you had a fixed test pattern or a circuit that would select only one line to display.

Do i need sometype of "video demodulator circuit" before the oscillscope so it displaces each line clearer??

What can i do to make it more clearer so its not so blurry and hazy looking?

What kind of waveform is this called when its superimposed like this?

Added after 50 seconds:

a circuit that would select only one line to display.

What circuit would do this please????

A video waveform analyser has a dial that lets you select any one of the 525 lines to look at. You could design one.

very funny audioguru

What are some oscillscope techniques that i can do to make the video waveforms look more clearer?

If your oscilloscope has "TV Trigger" or "Video Trigger" mode, then it may already be able to display individual scan lines, instead of many lines superimposed. Check the operator's manual. If your scope doesn't have that feature, try using single-sweep to display one line at random. Or try triggering on the beginning of the vertical field (sometimes difficult without a TV Trigger feature), and use the delayed sweep to view the desired scan line.

What model scope do you have?

If the video waveform looks horrible at slower sweep rates (a common problem with digital scopes), then try an analog oscilloscope. Here's how the composite video signal appears on a Tektronix 2465. The top image is at the horizontal rate, the bottom image is at the vertical rate. The camera is looking at different objects than my previous message.

Ya the second pictures look more like what i get on my oscilloscope

When i adjust the oscilloscope at slower sweep rate it shows more of the bits and pieces

The second pictures jPEG you have , what is it called? encoded? modulated?

is it encoded information? modulation information? interlaced?


How did you get to see your vertical sync, horzontial sync, colour burst? i don't get mine at all i wonder why?

Added after 2 minutes:

Here's how the composite video signal appears on a Tektronix 2465. The top image is at the horizontal rate, the bottom image is at the vertical rate.

1.) How did you set your oscilloscope to set it to the horizonatal RATE? and the other one to the vertical RATE?

"Bits and pieces" --- that sounds bad. Can you show us a screen image of the problem?

Composite video contains several types of encoding and modulation. Some of it is rather complex. To understand how it works, get yourself a broadcast engineering handbook.

The color burst is present in composite video, not in RGB or VGA. If you don't see any sync pulses, then they must be on another wire. My images show NTSC composite video. It's called "composite" because the one signal contains all the information necessary to create an image: luminance (brightness and contrast), chrominance (color hue and saturation), and sync timing.

NTSC is interlaced. So is PAL. VGA is usually not interlaced. RGB maybe or maybe not, depending on the source.

For horizontal rate, I set the sweep speed to 10us per division. For vertical rate, I set the it to 2ms per division.

why doesn't VGA and RGB have a colour burst?

I'm still not understanding about how you get the horizontal sync and vertical sync if they are MIXED and not on seperate wires

VGA has the RGB , horizontal sync, vertical sync on "seperate" wires right?

RGB component- has vertical sync, horizontal sync both MIXED on the green channel right?

Composite- has RGB , Horizontal,vertical sync all on ONE MIXED wire right? so the oscilloscope can not display seperate horizontal and vertical sync and RGB on the oscillscope with composite right?

Added after 42 minutes:


The hortizonal sync and vertical sync for all formats is TTL right?

I would need a sync seperator circuit i found out

Try reading the SMPTE 170M standard. It will answer most of your questions about the color burst and combined horizontal/vertical sync:
#415754

PAL composite video has many similarities to NTSC composite video, but it has some important differences too. If you need details, go find a broadcast engineering handbook.

Yes, VGA basically uses five signals: red, green, blue, vertical sync, and horizontal sync.

RGB comes in several flavors. The sync signal is usually a combined horizontal/vertical waveform (like NTSC or PAL sync) on the green signal, or it may be on all three color signals, or it may only be on a separate wire.

VGA sync is TTL level. NTSC sync pulses are about 0.28 volts (see my oscilloscope snapshots). PAL sync is about 0.30 volts. RGB sync is usually 0.28 or 0.30 volts too, even when it's on a separate wire, however I have seen TTL level sync on a separate wire.

VGA sync is TTL level. NTSC sync pulses are about 0.28 volts (see my oscilloscope snapshots). PAL sync is about 0.30 volts. RGB sync is usually 0.28 or 0.30 volts

Are theses all TTL level signals? for all of them?

for composite,component,RGB,VGA, etc all of them are TTL?

TTL levels are guaranteed to be at most 0.4V for a low and at least 2.4V for a high.

0.28V and 0.3V are no where near the TTL levels.

The output of an LM1881 sync separator IC is TTL levels. The datasheet shows a circuit that will select one horizontal line.

0.28V and 0.3V are no where near the TTL levels.

So if they aren't TTL signals what are they then or called?

Search for the book "Video Demystified" by Keith Jack. It will probably answer most of your questions.

Here's the 4th edition:
#825595

i just overlooked the pdf book and it doesn't answer my questions that much, but thanks its a nice book about color space for sure