| Electronics > Projects, Designs, and Technical Stuff |
| 3 Dollar Precision Frequency Standard |
| << < (10/12) > >> |
| netdudeuk:
That's the one that I have. Is there really no one on one on the EEVBLOG forum who can answer the harmonics question? :-// |
| netdudeuk:
Hi guys Still not having much joy with this project. I have this TCXO - http://www.ebay.co.uk/itm/Vectron-10MHz-TCXO-SMD-5V-2-5ppm-30C-75C-T1115-10M000000-Qty-2-/160999666268?pt=LH_DefaultDomain_0&hash=item257c53f25c It is running from a DP832 at 5v with the output going only to my 1054Z. According to the scope, the frequency constantly fluctuates and is always somewhere between 9.61 MHz and 10.1 MHz. Any idea why the output signal seems to be so far out of spec ? Thanks |
| TerminalJack505:
--- Quote from: netdudeuk on August 09, 2015, 11:22:56 am ---Hi guys Still not having much joy with this project. I have this TCXO - http://www.ebay.co.uk/itm/Vectron-10MHz-TCXO-SMD-5V-2-5ppm-30C-75C-T1115-10M000000-Qty-2-/160999666268?pt=LH_DefaultDomain_0&hash=item257c53f25c It is running from a DP832 at 5v with the output going only to my 1054Z. According to the scope, the frequency constantly fluctuates and is always somewhere between 9.61 MHz and 10.1 MHz. Any idea why the output signal seems to be so far out of spec ? Thanks --- End quote --- Are you using the scope's hardware counter? Or the software counter? Sounds like you might be using the software counter. |
| netdudeuk:
Ah ha ! So I was thanks. Enabling the counter in Measure > Counter gives me a very steady 10.0000MHz. Why would the frequency counter at the bottom of the screen be so flaky though ? Also, as you're on a winning streak so far, maybe you would also be able to answer my questions up above regarding me using a frequency counter with this circuit and only seeing the 2nd harmonic frequency ? :D Thanks |
| TerminalJack505:
From what I understand, the frequency measurement at the bottom of the screen bases its measurement on the captured waveforms. This is done in software so, as a tradeoff between speed and accuracy, they cut some corners in their calculation. (They likely don't account for partial cycles.) So far as your other problem goes, I can't say. It might be helpful if you posted the waveform. Maybe there's something about the waveform that is confusing the frequency counter. |
| Navigation |
| Message Index |
| Next page |
| Previous page |