- ... The picture of the single stand alone spike is what one of PC s has, the other four have the typical spike with noise going out quite a ways slowly andMessage 1 of 21 , Oct 1, 2006View SourceAlberto I2PHD wrote:
> Marco IK1ODO wrote:The picture of the single stand alone spike is what one of PC's has, the
>> There would be also a peak at 0Hz due to DC
>> imbalance of the ADC inputs, but the ADCs used in
>> 24bit souncards have an internal high pass filter
>> cutting under 1 or 2Hz, suppressing that.
> Marco is quite right, as demonstrated by these two screen captures. The
> first is the digitizing process carried on by Adobe Audition, using the
> onboard AC'97 chipset, with the card input left open. As you can easily
> see, there is a substantial DC offset produced by the ADC.
> The same chipset produced this strong zero frequency peak, entirely
> caused by the DC offset :
> 73 Alberto I2PHD
other four have the typical spike with noise going out quite a ways
slowly and meeting the noise floor about 2-3 KHz away.
On most PC's that is a rare item most people don't have that kind of
"Sacred Cows make the best Hamburger!" Don Seglio Batuna
- Spread Spectrum... CPU=AMD 2600 ECS is motherboadr mfg. KT-600 Dick N3HKN It is about 2 years old--- In firstname.lastname@example.org, Sam Morgan ... PC ...Message 2 of 21 , Oct 2, 2006View SourceSpread Spectrum...
ECS is motherboadr mfg. KT-600
It is about 2 years old--- In email@example.com, Sam Morgan
> n3hkn wrote:
> > I switched off the spread pectrum BIOS option in my "home made"
> > and the width of the noise spike is now vey narrow. Looks likealmost
> > a single frequency carrier.what cpu it's
> just curious, how new is your motherboard? I guess if u told me
> running that might also help. I'm thinking everything I have it toold, I don't
> remember seeing anything like that in the settings on any of them.
> GB & 73's
> Sam Morgan
- Yep, same here. Big peak at 0 with no inputs to D44. Totally goes away when 9V battery powered SR40V6 on-line. John JX________________________________From:Message 3 of 21 , Oct 2, 2006View SourceYep, same here. Big peak at 0 with no inputs to D44. Totally goes away when 9V battery powered SR40V6 on-line.John JX
From: firstname.lastname@example.org [mailto:email@example.com] On Behalf Of Mike
Sent: Sunday, 1 October 2006 00:41
Subject: [softrock40] Re: Big signal at 0 Hz even with SR40 is off
The big signal is 60 Hz pickup. The solution is isolation transformer
(s), in the audio lines and/or at the antenna connection. Running on
battery can help to, or a non-grounded power cube. These will help to
reduce the mountain at the center but may not eliminate it entirely.
73 - Mike WA8BXN
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