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-   -   Soundcard Test Results Thread (http://www.drmrx.org/forum/showthread.php?t=1749)

maxpower 07-06-2007 11:47

Soundcard Test Results Thread
 
Hi to all!

The computer based reception of DRM Transmisssions depends very much on the quality of the soundcards you use in your PC. I/Q-Receiver concepts, like the new SDR from Elektor, rely on that even more. So it's maybe useful to know, if your soundcard is capable for good reception.

Best test-setup for comparison would be to use the Soundcardtester from Elektor 07/05, available at AK-Modulbus (www.ak-modul-bus.de/stat/soundkartentester.html ) , explained at http://www.elexs.de/iq4.htm#tester, some other results and connection diagram at: http://www.b-kainka.de/iqrx3.htm


Please post your soundcard-test-results here for comparison.


Ok, the first results arrived and i try to make a summery here at the first post



Soundcards that should work very good with I/Q SDR's:








Soundcards that work good with I/Q SDR's:




Soundcards which you can use for start, but work less good:








Soundcards you should avoid for I/Q SDR use:





Note:

It seems to be that the level of image rejection can differ from one Soundcard-Tester to another one. So more or less image rejection in following posts don't need to mean weak image rejection in the real RX.



Stephan

maxpower 07-06-2007 12:02

1 Attachment(s)
The first test is the Realtek AC97 onBoard Soundcard at my Shuttle FS 31 Intel Processor (Intel Celeron 3.2 GHz) SIS based Chipset Computer which is operated with Windows Vista Home Premium.

I would estimate that other Realtek-AC97 onBoard Soundcards working on Intel-775-Processor based Mainboards should perform similar.

I use the Elektor/AK-Modulbus Soundcard-Tester with a 9 Volt Batterie (19 kHz Signal) for this test. I will repeat the with the recommended 6 Volts within the next days.

As far as i can judge this soundcard uses stereo input, but it's not good in antialiasing. SNR Ratio between Noisefloor and Information-Signal seem to be ok for me eyes.

So this soundcard is maybe capable for standard DRM Reception, but not recommended for I/Q (e.g. Elektor SDR) use.


Stephan

(PS: Please write to me if you think that some of my suggestions are wrong)

mitajohn 08-06-2007 15:01

2 Attachment(s)
Hi all,

Here is my test:
On board SoundMax soundcard, AC97, Analog Devices AD1981B/Intel Mb/P4-2.66GHz/Chipset Intel Brookdale i845PE/W2kpro.
Home made tester at 6VDC. The results before and after calibration show that SoundMax is good for I/Q.

dadalbinder 08-06-2007 15:55

Soundcard SoundMax
 
Hallo,

nice test result. I am able to work with the SoundMax too. Normal working is by Soundblaster Surround 5.1 USB. You have an excellent value for difference between the two channels. Should work very nice on the receiver.


As far as I see till now, Realtek seems not to be able.

Audigy 4: My experience told till now, that this is not able. Lets wait for the test-device.

Wolfgang H., 49N28, 11E00

mvs sarma 08-06-2007 19:57

Quote:

Originally Posted by mitajohn
Hi all,

Here is my test:
On board SoundMax soundcard, AC97, Analog Devices AD1981B/Intel Mb/P4-2.66GHz/Chipset Intel Brookdale i845PE/W2kpro.
Home made tester at 6VDC. The results before and after calibration show that SoundMax is good for I/Q.


Hi Mitajohn,

please suggest whether the 'onboard' sound card of Intel 915GLVG mother board with ALC860 audio codec, Realteck 5.10.0.5413 software,HD audio controller and with directx 9.0C could be suitabe for DRM and SDR use. i could not assertain whether the antialiasing filter is available in the above combination and if so how to configure the same for SDR compatibility . Please help me

mitajohn 08-06-2007 20:32

Hi mvs sarma,

Is the audio driver correct? Intel site shows this: http://downloadcenter.intel.com/Deta...032&lang= eng

You have to test the soundcard !

maxpower 08-06-2007 20:33

1 Attachment(s)
Ok, here's my next test: My old Soundblaster CT 4810

It seems to have a good antialiasing, but image-rejection isn't as good as at johns on-board-audio (which, btw, seems to be a really excellent audio-device!)

I think it should be suiteble for I/Q operations for starting, but not the very best choice for standard-operation.

maxpower 08-06-2007 20:38

1 Attachment(s)
Here's the next one: Sistermodel Creative Soundblaster Model 9916.

It doens't seem to have the same quality like the other Soundblaster model:an added carrier (low, but you can see it) is showing up on the right side of the spectrum. and i'm worried about the "foot" of the carrier-signal which is not very nice looking.

I am not sure if that would ruin I/Q reception because its not in the part of spectrum i normally would use for drm.

maxpower 08-06-2007 20:40

1 Attachment(s)
This is the result of my onboard C-Media cmi 9738:

The worst soundcard i have tested! Lots of carriers everywhere...

I say: Don't use this onboard-chip for I/Q or other SDR reception.

maxpower 08-06-2007 20:44

1 Attachment(s)
This is the older ALS 4000 PCI device. It's very difficult to find out best regulation for that card: if you set up volume to high, you get many carriers. If its to low, you will loose signal.

I would say: try it if you haven't got a better one, but try to change it as fast as you can. :-)

maxpower 08-06-2007 20:56

1 Attachment(s)
Ok, and here's the result of my audigy-4 soundcard. I think its a very ambivalent result: I hoped and thought it would perform better, particularly in 48 khz mode.

The carrier is at about -19 kHz and the spectrum till zero is ok, but on the other side there is a carrier which should't be there at +10 kHz! The next at +19 kHz is ok again.

I wonder why i can't null the image reception out as good as mitajohn at any device i have got. Or is it the ne555 at 9 Volt which messes me up in that problem?

Next test was in 96 kHz and at that rate the audigy worked very well without any aditional carriers (but only the multiples of 19 kHZ which is ok)

I found out some strange behavior: If i pull down the potentiometer to zero many carriers appear on the spectrum. Pull it up and they dissapear...

So, in result: Can i use it for I/Q operation or does the carrier at +10 kHZ ruin the signal in 48 kHz mode. And: can i run dream at 96 kHz?
Apart from that: How can it be that two same model-devices can be as different as mine and Wolfgangs device?

mitajohn 09-06-2007 09:02

2 Attachment(s)
Hi all,

Here is another test:
On board nVIDIA nForce2 MCP-T soundcard, AC97, Realtek ALC 650/Asus Mb/Athlon-1.66GHz/Chipset nVIDIA nForce2-U400/XP+.
Home made tester at 6VDC.
The results before and after calibration show that nVIDIA nForce2 MCP-T is another on board good soundcard for I/Q.

@Stephan. I believe that every good card for I/Q can be almost "zeroed", it is a bit tricky to find the best adjustment combination but it is feasible...

mitajohn 09-06-2007 10:26

2 Attachment(s)
Hi all,

Here is another test:
PCI/PNP soundcard Creative SoundBlaster Live! Player 1024/Asus Mb/Athlon-1.66GHz/Chipset nVIDIA nForce2-U400/XP+.
Home made tester at 6VDC.
The results before and after calibration show that Creative SoundBlaster Live! Player 1024 is a good PCI/PNP soundcard for I/Q with some minor byproducts.

mvs sarma 09-06-2007 11:05

Quote:

Originally Posted by mitajohn
Hi mvs sarma,

Is the audio driver correct? Intel site shows this: http://downloadcenter.intel.com/Deta...032&lang= eng

You have to test the soundcard !


I had later updated the driver

FritzWue 10-06-2007 09:30

Creative X-Fi
 
The Creative X-Fi works with Line In,
but cannot be better optimized with the test generator as shown.
For real life result see my next post.
The only 3.5mm input socket cannot be used if switched as Mic In.
Disappointing at that price. :(


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