Digital oscilloscope Jittery signal trace

[MarkL]

I don't see the frequency per division scale, or at least it's not clear to me.

You'll need to adjust you sweep in the time domain to improve your resolution.  And you'll want to set the maximum numbers of points, if it can be adjusted.

Take a look in vicinity of your carrier up to the digitizing rate.  If you can see it in the time domain, any interfering signal with a specific frequency will show up quite readily in the frequency domain.

You're looking for any peaks besides the main carrier if it's something besides noise.

It wouldn't hurt to verify your signal source on the SA also.  Make sure you have a single clean tone.

[uncle_bob]

For note: This shaky/jittery only can see with sinusoid waveform I check with 4 square signal
even with point to point CMOS oscillator and divider there is no shaky/jittery at all

Hi

A sine wave has a slow moving edge as it crosses the trigger point. A square wave is moving very quickly.

Example:

Sine wave takes 2 us to go 0.1V
Square wave takes 0.1 ns to go 0.1 V

If your scope is set to 2 us / division, you will never see any trigger issue on the square wave. It goes through the trigger region long before any of the noise in your environment has a chance to act.

Bob

[Theboel]

I don't see the frequency per division scale, or at least it's not clear to me.

You'll need to adjust you sweep in the time domain to improve your resolution.  And you'll want to set the maximum numbers of points, if it can be adjusted.

Take a look in vicinity of your carrier up to the digitizing rate.  If you can see it in the time domain, any interfering signal with a specific frequency will show up quite readily in the frequency domain.

You're looking for any peaks besides the main carrier if it's something besides noise.

It wouldn't hurt to verify your signal source on the SA also.  Make sure you have a single clean tone.

If hope this set of pic can help

[Theboel]

For note: This shaky/jittery only can see with sinusoid waveform I check with 4 square signal
even with point to point CMOS oscillator and divider there is no shaky/jittery at all

Hi

A sine wave has a slow moving edge as it crosses the trigger point. A square wave is moving very quickly.

Example:

Sine wave takes 2 us to go 0.1V
Square wave takes 0.1 ns to go 0.1 V

If your scope is set to 2 us / division, you will never see any trigger issue on the square wave. It goes through the trigger region long before any of the noise in your environment has a chance to act.

Bob

Hi Bob,
Bud also said a similar thing with You and the problem are its a hardware and software issue. I do not have capabilities to check the software issue but the hardware sure I can deal with it.
I will open soon the PLL section and run it in simulator I really hope can do a thing or two not to eliminated but at least reducing this problem.

Btw : I also check the PSU section and there is enough garbage came from this PSU to cause a lot of problem. I will try to filtering the PSU first there is nothing wrong have a clean PSU in this Oscilloscope, Right ?

[uncle_bob]

Btw : I also check the PSU section and there is enough garbage came from this PSU to cause a lot of problem. I will try to filtering the PSU first there is nothing wrong have a clean PSU in this Oscilloscope, Right ?

Hi

Since you started out fixing a power supply / cabling issue .... maybe that damaged something in the supply? Not knowing if the problem was internal or external to the scope, it's a bit tough to guess at some of this.

Bob

[Theboel]

Btw : I also check the PSU section and there is enough garbage came from this PSU to cause a lot of problem. I will try to filtering the PSU first there is nothing wrong have a clean PSU in this Oscilloscope, Right ?

Hi

Since you started out fixing a power supply / cabling issue .... maybe that damaged something in the supply? Not knowing if the problem was internal or external to the scope, it's a bit tough to guess at some of this.

Bob

Hi,
I am sure this problem came from internal of the scope,
What I wanna do with PSU is adding a few filtering thats all from the DC voltage measurement (without schematic) seem all voltage is reasonable to me.