| General > General Technical Chat |
| Review: Hantek DDS 3X25. Anyone own one? |
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| DaJones:
As a follow-up on the DDS-3x25... Here is an image of a 10mhz square wave with display persistence turned on. The jitter seems to always be +/- 5.5ns, no matter what the output frequency is. And here is a capture of the Sync-Out caught in the act of jittering. |
| saturation:
Thanks dajones, I think the jitter issue maybe real, and not a design defect. I'm due to get my unit in a few days, and I'll confirm whatever you already find. Jitter is a problem with synchronous signals assuming its not a scope issue, so this is not something you'd apply this device. On the good side, it seems the rise time on the square wave is good to 10MHz, suggesting it will produce a useful signal higher than 3MHz, but of questionable stability. Jitter aside, have you tried seeing its maximum frequency response on sine, and square at least, and how 'stable' they are? What harmonics on FFT are generated by its pure sine wave to its maximum frequency response? How is the output amplitude stability [we know a bit now of the frequency]? |
| Bored@Work:
Kids, mhz means nothing. mHz would be millihertz (10-3 Hz). But if you mean megahertz, then write MHz (106 Hz, or 1000000000 times larger than mHz). If that is to inconvenient for you, what about another hobby or profession? |
| Time:
--- Quote from: BoredAtWork on January 11, 2011, 06:02:04 pm ---Kids, mhz means nothing. mHz would be millihertz (10-3 Hz). But if you mean megahertz, then write MHz (106 Hz, or 1000000000 times larger than mHz). If that is to inconvenient for you, what about another hobby or profession? --- End quote --- Even if I have no interest in a thread topic and I see BoredAtWork has posted something on it I open it up anyways. Just so I can enjoy golden comments like this one. |
| DaJones:
--- Quote ---Kids, mhz means nothing. mHz would be millihertz (10-3 Hz). But if you mean megahertz, then write MHz (106 Hz, or 1000000000 times larger than mHz). If that is to inconvenient for you, what about another hobby or profession? --- End quote --- Thanks for the correction, BoredAtWork. That sounds familiar. I was in High School when the change was made from "cps" to "MHz", and even at that young age I was resistant to change. Maybe the fact that I disliked the change helps explain why I didn't absorb the details. And strictly in the spirit of sharing ( I don't normally do this ), I thought I would return the favor and point out a common grammatical error in your response. "If that is to inconvenient..." should be "If that is too inconvenient...". |
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