Author Topic: Siglent SDG1025 Square wave question  (Read 1194 times)

0 Members and 1 Guest are viewing this topic.

Offline tip29Topic starter

  • Newbie
  • Posts: 8
  • Country: us
Siglent SDG1025 Square wave question
« on: March 21, 2018, 11:34:08 pm »
Hi all,

I just bought Siglent SDG1025 function generator mainly to generate pwm signal for DC/DC converter (I am trying to learn DC/DC converters).
I found its output @ 4Vpp square wave has 1V overshoot and ringing. I have attached a picture below. Is this acceptable?? Looks terrible to me.
Also, the falling edge has 20ns jitter. I read about the jitter problem on some posts and the solution was to use pulse function. But the ringing on pulse function is even worse.

I am just a hobbyist and this is my first function generator. I feel like I should have just gotten a used agilent.

Thanks.
 

Online DaJMasta

  • Super Contributor
  • ***
  • Posts: 2289
  • Country: us
    • medpants.com
Re: Siglent SDG1025 Square wave question
« Reply #1 on: March 21, 2018, 11:39:10 pm »
Are you using a normal scope probe?  Have you tried connecting the BNC directly?

This is common because of the extra inductance of the probe's ground lead making a loop in the circuit and doesn't necessarily mean that it's actually being generated - it could be entirely an artifact of the way you are probing the signal.
 

Offline tip29Topic starter

  • Newbie
  • Posts: 8
  • Country: us
Re: Siglent SDG1025 Square wave question
« Reply #2 on: March 21, 2018, 11:51:10 pm »
I had BNC to minigrabber cable from the SDG connected to the probe of the oscilloscope.  The ringing diminished while probing BNC of the SDG directly.

I am stupid. :D

Thanks!
 

Offline tautech

  • Super Contributor
  • ***
  • Posts: 28142
  • Country: nz
  • Taupaki Technologies Ltd. Siglent Distributor NZ.
    • Taupaki Technologies Ltd.
Re: Siglent SDG1025 Square wave question
« Reply #3 on: March 21, 2018, 11:53:25 pm »
As DaJMasta says, your probing/measurement techniques are the reason for this.

All Siglent AWG's are designed for 50 \$\Omega\$ impedance loads so to display the waveform accurately you must terminate into a 50 ohm load. Try a BNC cable and a BNC 50 ohm feed through.

Another trap for young players is the Load setting in the Utility menu. Hi-Z or 50 ohm selection ONLY adjusts the output voltage to match the intended load and as mentioned above the output impedance is always 50 ohm.
Avid Rabid Hobbyist
Siglent Youtube channel: https://www.youtube.com/@SiglentVideo/videos
 

Online DaJMasta

  • Super Contributor
  • ***
  • Posts: 2289
  • Country: us
    • medpants.com
Re: Siglent SDG1025 Square wave question
« Reply #4 on: March 21, 2018, 11:54:04 pm »
I had BNC to minigrabber cable from the SDG connected to the probe of the oscilloscope.  The ringing diminished while probing BNC of the SDG directly.

I am stupid. :D

Thanks!

It's been a while, but I've done it too.  No worries  :P
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf