| ??? 03/10/06 22:25 Read: times |
#111942 - one more problem Responding to: ???'s previous message |
Thanks man, very neat drawing, it surely will help.
I put this lousy network at the output because my initial requirements was output frequency from 1 to 10 kHz. I need it up to 15 MHz now so I have to redesign the filter. I started inputting frequency on the LCD and another problem showed up, when I send commands from the DSP to the DDS one of them works perfect, the other one didn't work untill I added some delays in the FYSINC signal. My initial analysis was that the other one is slightly further away from the DSP and since there is no ground plane, noise might be getting at it. Tomorrow i will buy some surface mount resistors also and add it to the control lines of the dds as Kai suggested. It is fun to play with it, I started making frequency sweep up and down, watching it on the scope and spectrum is real fun. Mahmood |
| Topic | Author | Date |
| AD9835 noise problem | 01/01/70 00:00 | |
| noise | 01/01/70 00:00 | |
| Recommendations | 01/01/70 00:00 | |
| quick fix? | 01/01/70 00:00 | |
| Maybe | 01/01/70 00:00 | |
| Transmission lines | 01/01/70 00:00 | |
| 5MHz? | 01/01/70 00:00 | |
| Spectrum analyser | 01/01/70 00:00 | |
| It's ground noise | 01/01/70 00:00 | |
| ground noise and groundhogs | 01/01/70 00:00 | |
| Harmonics as well | 01/01/70 00:00 | |
| comments | 01/01/70 00:00 | |
| Why separate the analog & digital gnds? | 01/01/70 00:00 | |
| Splitting the ground plane | 01/01/70 00:00 | |
| Evaluation board | 01/01/70 00:00 | |
| thin ground? | 01/01/70 00:00 | |
| that is why you use star | 01/01/70 00:00 | |
| Ground wire in parallel | 01/01/70 00:00 | |
| and a twisted pair? | 01/01/70 00:00 | |
| Would do! | 01/01/70 00:00 | |
| does not exist, Jan if you used twisted | 01/01/70 00:00 | |
| The clock signal? | 01/01/70 00:00 | |
| oh well | 01/01/70 00:00 | |
| Indeed | 01/01/70 00:00 | |
| is there a way... | 01/01/70 00:00 | |
| Hardly | 01/01/70 00:00 | |
| unfortunately not | 01/01/70 00:00 | |
| twisted pair | 01/01/70 00:00 | |
| is that not obvious | 01/01/70 00:00 | |
| No ground traces, but patches | 01/01/70 00:00 | |
| the bane of many | 01/01/70 00:00 | |
| Why 1 or 2 layers | 01/01/70 00:00 | |
| it's nice! | 01/01/70 00:00 | |
| No Secrets | 01/01/70 00:00 | |
| DALO 2M professional | 01/01/70 00:00 | |
| UV ink Problem | 01/01/70 00:00 | |
| Mixed method? | 01/01/70 00:00 | |
| No Need for DALO | 01/01/70 00:00 | |
| CE | 01/01/70 00:00 | |
| Single step mode | 01/01/70 00:00 | |
| If you want... | 01/01/70 00:00 | |
| mmm | 01/01/70 00:00 | |
| Dreaming | 01/01/70 00:00 | |
| LAYOUT | 01/01/70 00:00 | |
| 100nF caps | 01/01/70 00:00 | |
| 100nF ? | 01/01/70 00:00 | |
| ok | 01/01/70 00:00 | |
| Some checks | 01/01/70 00:00 | |
| It's my daily job! | 01/01/70 00:00 | |
| Unfortunately, no | 01/01/70 00:00 | |
| simulate double-layer | 01/01/70 00:00 | |
| Seperate Analog and Digital Supply | 01/01/70 00:00 | |
| RLC-filters don't help? | 01/01/70 00:00 | |
| separate | 01/01/70 00:00 | |
| And... | 01/01/70 00:00 | |
| Seperate Supplies | 01/01/70 00:00 | |
| Evaluation board | 01/01/70 00:00 | |
| No not that one... | 01/01/70 00:00 | |
| Curly | 01/01/70 00:00 | |
| OT: Hair | 01/01/70 00:00 | |
| lets have pictures | 01/01/70 00:00 | |
| No no... | 01/01/70 00:00 | |
| http://www.k6ese.com/Mar_Vista_Shack.htm | 01/01/70 00:00 | |
| but it is relevant | 01/01/70 00:00 | |
| No wonder... | 01/01/70 00:00 | |
| waveforms | 01/01/70 00:00 | |
| Link to DDS page | 01/01/70 00:00 | |
| Add the second stage... | 01/01/70 00:00 | |
| Filter components | 01/01/70 00:00 | |
| clock | 01/01/70 00:00 | |
| What clock | 01/01/70 00:00 | |
| ? | 01/01/70 00:00 | |
| Sampling theorem | 01/01/70 00:00 | |
| But... | 01/01/70 00:00 | |
| Can't find it now | 01/01/70 00:00 | |
| Ground of probe? | 01/01/70 00:00 | |
| even better | 01/01/70 00:00 | |
| Good trick! | 01/01/70 00:00 | |
| same point | 01/01/70 00:00 | |
| Both | 01/01/70 00:00 | |
| I feel strong now! | 01/01/70 00:00 | |
| Funny! | 01/01/70 00:00 | |
| Depends... | 01/01/70 00:00 | |
| Oh Dear | 01/01/70 00:00 | |
| NO analog outputs | 01/01/70 00:00 | |
| since there is no schematics presented | 01/01/70 00:00 | |
| Publishing failed | 01/01/70 00:00 | |
| then give a link to an ORCAD drawing | 01/01/70 00:00 | |
| Schematics | 01/01/70 00:00 | |
| corrections | 01/01/70 00:00 | |
| Big test | 01/01/70 00:00 | |
| Try This Schematic... | 01/01/70 00:00 | |
| one more problem | 01/01/70 00:00 | |
| I miss the second 300R resistor | 01/01/70 00:00 | |
| Terminating Resistor. | 01/01/70 00:00 | |
| Answers | 01/01/70 00:00 | |
| University of Kai | 01/01/70 00:00 | |
| Keep us informed... | 01/01/70 00:00 | |
| of course | 01/01/70 00:00 | |
| Update | 01/01/70 00:00 | |
| Eager to know | 01/01/70 00:00 | |
| Me too | 01/01/70 00:00 | |
| Autoreload | 01/01/70 00:00 | |
| Current source output | 01/01/70 00:00 | |
| Electronic World Feb 06 | 01/01/70 00:00 | |
| Superb! | 01/01/70 00:00 | |
| No surprise | 01/01/70 00:00 | |
| AD9835 Cycles | 01/01/70 00:00 | |
| Solid Ground Plane Update!!!!! | 01/01/70 00:00 | |
| Very nice results! | 01/01/70 00:00 | |
| Low frequency | 01/01/70 00:00 | |
| SLIGHt correction | 01/01/70 00:00 | |
| OPA27? | 01/01/70 00:00 | |
| Cross talk on PCB tracks | 01/01/70 00:00 | |
| Have a look at this plot | 01/01/70 00:00 | |
| Interesting question | 01/01/70 00:00 | |
further interesting question | 01/01/70 00:00 |