The last thing i dont understand in the schematic: help!

The operation of transmitters designed to jam or block wireless communications is a violation of the Communications Act of 1934, as amended ("Act"). See 47 U.S.C. Sections 301, 302a, 333. The Act prohibits any person from willfully or maliciously interfering with the radio communications of any station licensed or authorized under the Act or operated by the U.S. government. 47 U.S.C. Section 333. The manufacture, importation, sale or offer for sale, including advertising, of devices designed to block or jam wireless transmissions is prohibited. 47 U.S.C. Section 302a(b). Parties in violation of these provisions may be subject to the penalties set out in 47 U.S.C. Sections 501-510. Fines for a first offense can range as high as $11,000 for each violation or imprisonment for up to one year, and the device used may also be seized and forfeited to the U.S. government.

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Freemo
 
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The last thing i dont understand in the schematic: help!

Post by Freemo »

Hey guys. So ive been pouring over this schematic in an attempt to gain an understanding of how to actually implement a PLL. I was suprised to find that i understood every part of the schematic, except one. There is a point int he schematic labeled "noise source" consisting of a zener diode at its heart. The problem is this seems to have a floating output that doesnt connect to anything at all in the schematic. So im forced to ask, where does the noise source connect to in the schematic?

Here is a link to the schematic: http://www.ladyada.net/media/wavebubble ... 20RC1a.pdf

Oh and PS, I plan to sell kits and pre-assembled versions of the wave bubble in my online store very soon (thus the research). So if you want the pcb's and parts in a kit, or even pre-assembled let me know and ill notify you the moment their put up for sale on the site.

------------------------
Your open-source friend,
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Check out http://www.syncleus.com for open source hardware, software, wiki, and shop. All kits and devices provide complete schematics and board layouts! Wave Bubble coming soon!

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aqisnotliquid
 
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Re: The last thing i dont understand in the schematic: help!

Post by aqisnotliquid »

The operation of transmitters designed to jam or block wireless communications is a violation of the Communications Act of 1934, as amended ("Act"). See 47 U.S.C. Sections 301, 302a, 333. The Act prohibits any person from willfully or maliciously interfering with the radio communications of any station licensed or authorized under the Act or operated by the U.S. government. 47 U.S.C. Section 333. The manufacture, importation, sale or offer for sale, including advertising, of devices designed to block or jam wireless transmissions is prohibited. 47 U.S.C. Section 302a(b). Parties in violation of these provisions may be subject to the penalties set out in 47 U.S.C. Sections 501-510. Fines for a first offense can range as high as $11,000 for each violation or imprisonment for up to one year, and the device used may also be seized and forfeited to the U.S. government.
Might want to watch out for that.

Freemo
 
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Re: The last thing i dont understand in the schematic: help!

Post by Freemo »

I'm well aware of it and already have that taken care of. But thank you for the concern. The sale will commence as planned. Already had the lawyers side of things covered.

Freemo
 
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Re: The last thing i dont understand in the schematic: help!

Post by Freemo »

Uh-Oh! no replies with help. Im afraid this may be a job for ladyada herself! Although she is way to famous for the likes of this thread :)

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aqisnotliquid
 
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Re: The last thing i dont understand in the schematic: help!

Post by aqisnotliquid »

Ladyada does in fact browse these forums to help people out where she can. And based on the fact that your problem doesn't seem solvable by anyone that's fairly active, she may pop in and reply. Who knows?

I'd help, but I haven't bothered to pour over the schematic for it. I supply the PCB's, but I don't really have any plans for actually building one. Otherwise, I'd be glad to help.

Good luck, and I hope that the problem gets solved! You may want to try sending her an email if you don't hear from her in a week or two.

Freemo
 
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Re: The last thing i dont understand in the schematic: help!

Post by Freemo »

Thanks for the reply. I considered sending her an email, not just over this but I also wanted to make sure i didnt offend her by selling this. But I figured she is probably bugged far too often as it is. If i dont get an answer in a week or two though i may consider that. Thanks.

neutered
 
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Re: The last thing i dont understand in the schematic: help!

Post by neutered »

[quote="Freemo"]Hey guys. So ive been pouring over this schematic in an attempt to gain an understanding of how to actually implement a PLL. I was suprised to find that i understood every part of the schematic, except one. There is a point int he schematic labeled "noise source" consisting of a zener diode at its heart. The problem is this seems to have a floating output that doesnt connect to anything at all in the schematic. So im forced to ask, where does the noise source connect to in the schematic?
[/quote]

the errata at

http://ladyada.net/wiki/wavebubble/errata

says that this is part of the (now unused) noise circuit, and is now dnp.

neutered
 
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Re: The last thing i dont understand in the schematic: help!

Post by neutered »

on the subject of zener diodes for noise, there are hw random # generators that uses zeners to generate their bitstreams. google-ing gives somewhat vague information, but anyone out there really know how this works? is the zener's avalanche point non-deterministic? something else?

Freemo
 
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Re: The last thing i dont understand in the schematic: help!

Post by Freemo »

neutered wrote: the errata at

http://ladyada.net/wiki/wavebubble/errata

says that this is part of the (now unused) noise circuit, and is now dnp.
Well that just open new questions. If the noise source isnt being used anymore, where is the static comming from? Or does sweeping the frequency range, while not technically static, cause the interference itself somehow?

neutered
 
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Re: The last thing i dont understand in the schematic: help!

Post by neutered »

Freemo wrote:
neutered wrote: the errata at

http://ladyada.net/wiki/wavebubble/errata

says that this is part of the (now unused) noise circuit, and is now dnp.
Well that just open new questions. If the noise source isnt being used anymore, where is the static comming from? Or does sweeping the frequency range, while not technically static, cause the interference itself somehow?
'sweeping' will be doing the jaming if that's waht you mean by 'interference'.

i'm a little confused now too. my understanding was taht the noise was useful to avoid detection of the jamming circuit (the signal will be too clean to be anything other than active jamming). if you look at http://www.ladyada.net/make/wavebubble/vco.html
there's an image of the spectrum analyzer running the test_vco function. the bandwidth sweep looks pretty clean (although when it does the dc offset sweep the spike definitely flattens to cover more area w/ less power).

anyway, i don't have access to a spectrum analyzer (and tehre are no similar images w/ the final output), but can anyone who has finished theirs (i'm still gathering parts by piggybacking onto orders :-) confirm noise?

neutered
 
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Re: The last thing i dont understand in the schematic: help!

Post by neutered »

this was my reply to a pm, but i figured i'd reflect this back to the forum so that wiser minds could opine.
neutered wrote:
neutered wrote: 'sweeping' will be doing the jaming if that's waht you mean by 'interference'.
Why would simply sweeping cause active jamming? I know if you transmit dead air (nothing modulated on top just the carrier signal) at a particular frequency you will get silence. However when that is at the same time as an active modulated signal then a receiver should still be able to pick up the active signal over the unmodulated silent signal. So i dont see how transmitting an unmodulated carrier without any static on the cellphone frequencies produces jamming.
i'm not an expert on the cellphone modulations (or rf in general), but my thinking is that the sweep is 'adding' to the signal in the frequency domain.

to my simplistic analysis for digital information, the carrier is at Fc and modulation is at Fm. if we have a fixed carrier (disregard frequency hopping and spread spectrum) broadcasting at Fm would give the equivilant of a 'stuck bit'. sweeping across the band covers a larger range of the possible Fm (for multiple channels and different modulations schemes like ofdm).
the same holds for the sweep across a Fc as well since this would look like a 'zero' w/o anything at the corresponding Fm.

Freemo
 
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Re: The last thing i dont understand in the schematic: help!

Post by Freemo »

Thanks. Im still a bit skeptical that this is the mechanism at play. But its the best theory i got. Ill have to pick apart my wavebubble with a O-scope and spectrum analyzer and see what i get. Thanks for all the input.

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