Pages: 1 2 [3] 4 
|
 |
|
|
Author
|
Topic: DDC Module2 (Read 46896 times)
|
|
|
|
N7DDC
Neuling
 Offline
Posts: 9
I'm a llama!
|
 |
Re:DDC Module2
« Reply #31 on: 27. September 2020, 01:45:52 »
|
|
Hello, Artur
Set the amplificator in settings to see the noise with no antenna.
Later I will correct the bitwise shift.
|
|
 Logged
|
|
|
|
|
|
SP9BSL
positron
alter Hase
Offline
Posts: 443
|
|
Re:DDC Module2
« Reply #33 on: 27. September 2020, 07:27:03 »
|
|
Just set the RX codec gain to 0 and you will see the noise floor. This is not a bug, known behaviour. We will adjust the AGC for spectrum later.
|
|
Logged
|
73 Slawek
|
|
|
S58J
schon länger dabei
Offline
Posts: 100
Ich liebe dieses Forum!
|
|
Re:DDC Module2
« Reply #34 on: 28. September 2020, 10:23:22 »
|
|
Hi
I am trying to follow this discussion, strictly from a user perspective (always building a new and BETTER transceivers). Saying that I have to admit that I am not qualified to make comments about the current developments (Sparkle, N7DCC approach, ...). I love to solder and use home transceivers while I am not too much knowledgeable about the "magic behind" each TRX.
I used Google extensively (hi) trying to better understand why adding N7DDC module would made future TRX home made projects even better - in performance of course.
However I would be grateful if someone can explain in easy language why it is better (or not) to include DDC module vs. "traditional" approach (with WM sound ICs) such as OVI40 UI PCB. I guess this kind of information would be good (and educational) for other forum followers as well.
Thank you in advance
Janez, S58J
|
|
Logged
|
|
|
|
|
|
S58J
schon länger dabei
Offline
Posts: 100
Ich liebe dieses Forum!
|
|
Re:DDC Module2
« Reply #36 on: 28. September 2020, 12:13:52 »
|
|
Hi Andreas
Thank you for your quick reply. Just to be shure, when you list those bullets under "You do not have" you are talking about the simplicity/benefits of using OVI40 UI, am I right?
In terms of quality of each TRX I have two indicators: quality of RX and clean TX output. OK, the list goes on (frequency stability, filtering capabilities ...) but those two just listed are the major concerns for me.
If this DDC thread doesn't bring much to the table in the RX and TX area then we are coming back to the old philosophy: simpler is better. I'll stick to my OVI40 UI, hi.
Please take this as my own opinion, a person keen on HF contesting (high power), QRP operation (where I use only home made QRPs) and hunting DX on 50MHz. Others, more technical and development oriented persons, for shure might think differently.
Looking forward to your reply.
Janez, S58J
|
|
Logged
|
|
|
|
|
|
SP9BSL
positron
alter Hase
Offline
Posts: 443
|
|
Re:DDC Module2
« Reply #38 on: 28. September 2020, 15:20:42 »
|
|
The DDC receiver is better
|
|
Hi Artur,
There is something wrong with your receiver based on mcHF: the picture with -101dBm is at least 10dB higher than usual mcHF does, on the other side with DDC you show -133dBm which is too low. Did you calibrated the s-meter?
|
| « Last Edit: 28. September 2020, 16:02:30 by SP9BSL » |
Logged
|
73 Slawek
|
|
|
DD4WH
positron
alter Hase
Offline
Posts: 462
Ich liebe dieses Forum!
|
|
Re:DDC Module2
« Reply #39 on: 28. September 2020, 17:31:46 »
|
|
Hi!
this looks like a very interesting development. However, I have not yet understood how/whether it can be used with existing OV I40 UI PCBs. Is this possible?
Or would it be better to build a Sparrow UI (is there anything called like this?) which has a possibility to plugin the DDC module?
Is there a place where I can read more about this project?
73 Frank DD4WH
|
|
Logged
|
-----------------------------------------
Teensy Convolution SDR
https://github.com/DD4WH/Teensy-ConvolutionSDR
|
|
|
SP9BSL
positron
alter Hase
Offline
Posts: 443
|
|
Re:DDC Module2
« Reply #40 on: 28. September 2020, 19:19:35 »
|
|
For the Gain RX ->AUTO< setting (correct s-metr >0<), the DSP chip is as shown in the photo. OK?
|
|
if you like then ok...
Leaving the codec gain to AUTO you add 24dB, sometimes less - it depends on AGC algorithm. In codec there is volume control but in fpga you haven't such thing. This is simple codec not a DSP.
A picture is better than thousand of words. The rx path is calibrated to S9 signal - as it should be, amplifier/attenuator are off and the shields are open. Antenna input left floating (same settings for both pictures):
|
73 Slawek
|
|
|
|
|
DD4WH
positron
alter Hase
Offline
Posts: 462
Ich liebe dieses Forum!
|
|
Re:DDC Module2
« Reply #42 on: 29. September 2020, 08:39:40 »
|
|
Hi Andreas,
thanks for your explanations!
It is very hard for me to get an idea about this project, because there is virtually no information available (schematics, block diagram).
So, I understand that its still experimental and the DDC/DUC plugin does substitute the codec and the QSD and QSE.
Thanks again for the info!
73 Frank DD4WH
|
|
Logged
|
-----------------------------------------
Teensy Convolution SDR
https://github.com/DD4WH/Teensy-ConvolutionSDR
|
|
|
|
|
|
|
Pages: 1 2 [3] 4 
|
|
|
|
|
|
|
RX-fpga.png
TX-fpga.png
