From mohammadaj at gmail.com Thu Apr 1 21:54:54 2010 From: mohammadaj at gmail.com (mohamad al-jamal) Date: Thu, 1 Apr 2010 23:54:54 +0300 Subject: [Ronja] new receiver design In-Reply-To: <1269942331.11390.9.camel@core-laptop> References: <9061a4381003272004j61ac9eafyc007b36e9a621a6f@mail.gmail.com> <1269895998.9782.18.camel@core-laptop> <9061a4381003291603i2d2d6907q2a5a830ace56df14@mail.gmail.com> <1269942331.11390.9.camel@core-laptop> Message-ID: happy easter to all ... gullik , do you mean the filter should look like in this image ?? i think we need a freewheeling diode after the L , don't you think ?? http://img163.imageshack.us/img163/668/filterj.jpg as for the noise , actually we happen to have a crappy old oscilloscope ... i might be able to obtain a better one after the holidays .. On Tue, Mar 30, 2010 at 12:45 PM, Gullik Webj?rn < gullik.webjorn at corevalue.se> wrote: > On Tue, 2010-03-30 at 02:03 +0300, mohamad al-jamal wrote: > > the design is performing very nicely ... distance without lenses was > > roughly 1.5m . i'am still experimenting though ... as for the > > sensitivity and noise , i intend to increase the feedback resistor to > > 400K or so , it will form a pole almost at the same point inferno > > does , but with better sensitivity and noise performance ( at least > > theoretically !!) .. the signal at the output of the TIA is a > > sawtooth with 450mV p-p ... i don't know how to measure the noise > > properly !! but without an optical signal,we get a random noise > > (without oscillations) with about 80mV p-p . > > My simplistic view 450/80 = 15 dB. If you use a good oscilloscope, > measure the signal, then increase gain and measure vertical "thickness" > of the trace, this works best on a square wave. > > > the strange thing we found is that the smaller R3 is , the better the > > performance gets !! any explanation !?!? as for the B.W , we used a > > function generator as a signal source , and the we ranged the > > frequency from 1MHz up to 13MHz or so , and nothing went wrong .. > > > Measure voltage drop across R3 on various signal conditions. Maybe > you find you are saturating the pin, causing large voltage drop, > decreasing bias on PIN, causing less gain. > > What about a small R3, cap to ground, small L (ind), cap to ground?? > Since the other node, PIN cathode goes to OP input / feedback resistor, > a low R3 will not increase risk of excessive current in PIN. > > Regards, > > Gullik > > > _______________________________________________ > Ronja mailing list > Ronja at lists.pointless.net > http://pointless.net/mailman/listinfo/ronja > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pointless.net/pipermail/ronja/attachments/20100401/b5807beb/attachment.html From twibright at hispeed.ch Tue Apr 6 16:13:53 2010 From: twibright at hispeed.ch (Karel Kulhavy) Date: Tue, 6 Apr 2010 17:13:53 +0200 Subject: [Ronja] new receiver design Message-ID: <22655766.1270566834752.JavaMail.root@viefep14> ---- "Gullik Webj?rn" schrieb: > Hello Mohamad, > > It is interesting to see people working on implementing the > design with more modern components. How is your design performing? > > Have you compared sensitivity vs. noise against the standard frontend? > > What bandwidth are you getting? > > As for R3 in your schematic, if forms a pole with the 100 nF, at below > a khz, so the noise contribution from R3 should be minimal in the band > of interest, Mhz, I believe. The BPV10 is a good one, OPA905 is also a > useful PIN, and readily available. > > I think you should be *very* careful with filtration of supply voltages, > after all you will be building a high bandwidth "straight receiver" so > the risk of unwanted feedback is there all the time. Shielding will be > required, you will be running 120 + dB gain in the entire chain. Yeah, Ronja has about 120dB gain, more than the first telecommunications satellite (Telstar, 100dB) :) Karel > > Good luck, > > Gullik > > > On Sun, 2010-03-28 at 06:04 +0300, mohamad al-jamal wrote: > > Dear all > > > > I have been trying to modify the Ronja inferno receiver for the sake > > of better performance .. i have replaced the first stage > > ( transimpedance amplifier ) with a conventional configuration : an > > opamp with an RC feedback circuit .. instability is avoided by > > inserting a relatively high capacitor in the feedback circuit .. the > > bandwidth is ruined though , therefore the NE592 is used - just like > > in inferno - to compensate for the integrator effect of the TIA . i > > used a high bandwidth opamp from texas instruments (OPA657) . and used > > another PIN photodiode , a cheap one from vishay > > (http://www.vishay.com/docs/81503/bp10nf.pdf) . the PIN is directly > > biased by a -12 supply . and every thing went just fine !! the signal > > was nice and clean . i'am still experimenting , but it seems > > promising . this image illustrates the new configuration . > > http://img265.imageshack.us/i/rxfirststage.jpg/ > > > > i have a couple of questions though : > > regarding R3 in the schematics , i thought that R3 should be as high > > as possible in order to avoid thermal noise ... is that true ? > > regarding the filtration practice of the supply connected to the PIN , > > is the configuration in the image sufficient ? > > > > any ideas are highly appreciated . > > > > > > > > > > _______________________________________________ > > Ronja mailing list > > Ronja at lists.pointless.net > > http://pointless.net/mailman/listinfo/ronja > > > > _______________________________________________ > Ronja mailing list > Ronja at lists.pointless.net > http://pointless.net/mailman/listinfo/ronja From twibright at hispeed.ch Tue Apr 6 16:29:01 2010 From: twibright at hispeed.ch (Karel Kulhavy) Date: Tue, 6 Apr 2010 17:29:01 +0200 Subject: [Ronja] (no subject) Message-ID: <3931665.1270567741909.JavaMail.root@viefep14> ---- Ymktwo schrieb: > Hi like to check if any one try before beaming from inside a glass window > to another site? Yeah few Internet trunks run like this in Prague for many years at Bakulak It's no problem. I would recommend though if you have old window with an old uneven glass throw a brick through it and replace with modern float glass which is more straight :) Karel > ? > I would like to place the transmitter and RX in side the building . > ? > > Wallace Yaw > > Cheers always!!! Stay Happy My friends! New Email names for you! Get the Email name you've always wanted on the new @ymail and @rocketmail. Hurry before someone else does! http://mail.promotions.yahoo.com/newdomains/sg/ From gullik.webjorn at corevalue.se Wed Apr 7 00:24:01 2010 From: gullik.webjorn at corevalue.se (Gullik =?ISO-8859-1?Q?Webj=F6rn?=) Date: Wed, 07 Apr 2010 01:24:01 +0200 Subject: [Ronja] (no subject) In-Reply-To: <3931665.1270567741909.JavaMail.root@viefep14> References: <3931665.1270567741909.JavaMail.root@viefep14> Message-ID: <1270596241.2230.9.camel@core-laptop> A single glass sheet has if I remember correctly, about 7% loss, or 0.5 dB. A window might have 2 or 3 panes. Also if both TX and remote RX are located behind windows, well, "interest on interest". Some window glasses might have coatings that prevent dirt from accumulating, or other wavelength sensitive coatings, so beware, and measure signal. With two single lenses this is only 13% of available power, but it can easily add up. Also, watch the angle, so you don' t approach total reflection.. Gullik On Tue, 2010-04-06 at 17:29 +0200, Karel Kulhavy wrote: > ---- Ymktwo schrieb: > > Hi like to check if any one try before beaming from inside a glass window > > to another site? > > Yeah few Internet trunks run like this in Prague for many years at Bakulak > It's no problem. > > I would recommend though if you have old window with an old uneven glass throw a brick through it and replace with modern float glass which is more straight :) > > Karel From mohammadaj at gmail.com Thu Apr 15 19:21:47 2010 From: mohammadaj at gmail.com (mohamad al-jamal) Date: Thu, 15 Apr 2010 21:21:47 +0300 Subject: [Ronja] new receiver design In-Reply-To: <22655766.1270566834752.JavaMail.root@viefep14> References: <22655766.1270566834752.JavaMail.root@viefep14> Message-ID: hey guys the receiver is working just fine ... with 220K feedback resistor SNR is enhanced dramatically ... the output of the TIA without an optical signal was reduced to 5mV p-p .. and the signal was about 400mV p-p .. the range was increased by a factor of 25% (without lenses ) .. i forgot to tell you that we have modified the transmitter as well . we used a cheap IR LED from vishay TSFF5210 (http://www.vishay.com/docs/81090/tsff5210.pdf) .. this image illustrates the new configuration .. http://img100.imageshack.us/i/txfinal.jpg/ i need your comments please . On Tue, Apr 6, 2010 at 6:13 PM, Karel Kulhavy wrote: > ---- "Gullik Webj?rn" schrieb: > > Hello Mohamad, > > > > It is interesting to see people working on implementing the > > design with more modern components. How is your design performing? > > > > Have you compared sensitivity vs. noise against the standard frontend? > > > > What bandwidth are you getting? > > > > As for R3 in your schematic, if forms a pole with the 100 nF, at below > > a khz, so the noise contribution from R3 should be minimal in the band > > of interest, Mhz, I believe. The BPV10 is a good one, OPA905 is also a > > useful PIN, and readily available. > > > > I think you should be *very* careful with filtration of supply voltages, > > after all you will be building a high bandwidth "straight receiver" so > > the risk of unwanted feedback is there all the time. Shielding will be > > required, you will be running 120 + dB gain in the entire chain. > > Yeah, Ronja has about 120dB gain, more than the first telecommunications > satellite > (Telstar, 100dB) :) > > Karel > > > > > Good luck, > > > > Gullik > > > > > > On Sun, 2010-03-28 at 06:04 +0300, mohamad al-jamal wrote: > > > Dear all > > > > > > I have been trying to modify the Ronja inferno receiver for the sake > > > of better performance .. i have replaced the first stage > > > ( transimpedance amplifier ) with a conventional configuration : an > > > opamp with an RC feedback circuit .. instability is avoided by > > > inserting a relatively high capacitor in the feedback circuit .. the > > > bandwidth is ruined though , therefore the NE592 is used - just like > > > in inferno - to compensate for the integrator effect of the TIA . i > > > used a high bandwidth opamp from texas instruments (OPA657) . and used > > > another PIN photodiode , a cheap one from vishay > > > (http://www.vishay.com/docs/81503/bp10nf.pdf) . the PIN is directly > > > biased by a -12 supply . and every thing went just fine !! the signal > > > was nice and clean . i'am still experimenting , but it seems > > > promising . this image illustrates the new configuration . > > > http://img265.imageshack.us/i/rxfirststage.jpg/ > > > > > > i have a couple of questions though : > > > regarding R3 in the schematics , i thought that R3 should be as high > > > as possible in order to avoid thermal noise ... is that true ? > > > regarding the filtration practice of the supply connected to the PIN , > > > is the configuration in the image sufficient ? > > > > > > any ideas are highly appreciated . > > > > > > > > > > > > > > > _______________________________________________ > > > Ronja mailing list > > > Ronja at lists.pointless.net > > > http://pointless.net/mailman/listinfo/ronja > > > > > > > > _______________________________________________ > > Ronja mailing list > > Ronja at lists.pointless.net > > http://pointless.net/mailman/listinfo/ronja > > > _______________________________________________ > Ronja mailing list > Ronja at lists.pointless.net > http://pointless.net/mailman/listinfo/ronja > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pointless.net/pipermail/ronja/attachments/20100415/20054d68/attachment.html From gullik.webjorn at corevalue.se Thu Apr 15 21:10:25 2010 From: gullik.webjorn at corevalue.se (Gullik =?ISO-8859-1?Q?Webj=F6rn?=) Date: Thu, 15 Apr 2010 22:10:25 +0200 Subject: [Ronja] new receiver design In-Reply-To: References: <22655766.1270566834752.JavaMail.root@viefep14> Message-ID: <1271362225.4695.8.camel@core-laptop> > the receiver is working just fine ... with 220K feedback resistor SNR > is enhanced dramatically ... the output of the TIA without an optical > signal was reduced to 5mV p-p .. and the signal was about 400mV p-p .. > the range was increased by a factor of 25% (without lenses ) .. i > forgot to tell you that we have modified the transmitter as well . we > used a cheap IR LED from vishay TSFF5210 > (http://www.vishay.com/docs/81090/tsff5210.pdf) .. this image > illustrates the new configuration .. 20 * log10( 400/5 ) = 38 dB. Do I understand correctly, at 2.5 m range without lenses, you have 38 dB SNR ?? If so, then this is definitely a large improvment. You should need 20 dB or so, the remaining 18 could be traded for range. How are you measuring level, O-scope? If so, what is the rise time of the signal after receiver? ( time from 10% to 90% ) > http://img100.imageshack.us/i/txfinal.jpg/ > > i need your comments please . So, essentially this is just a LED (and resistor ) change to "red" ronja. The bandwidth of the HPWT and the TSFF5210 seems very similar. Seems you are making progress.... Gullik From mohammadaj at gmail.com Tue Apr 27 15:25:12 2010 From: mohammadaj at gmail.com (mohamad al-jamal) Date: Tue, 27 Apr 2010 17:25:12 +0300 Subject: [Ronja] twwister2 not working Message-ID: Dear all i have two twisters2 along with two Tx's and Rx's ... i can see the 1MHz signal at the output of the Rx's ... when i connect the UTP to the NIC the red LED starts to flicker , on the other twister the green LED start to flicker , but the two PC's never get connected , they just keep acquiring an IP ... the switches' positions are correct , and the UTP strands are connected correctly !!!!.. i noticed a strange thing ... when i put the probes of the oscilloscope on the transmitting pair of the UTP the green LED on both twisters starts to flicker . any explanation !?!? another thing ... i configured the interfaces as if they were connected via a crossover cable ... i'am not sure this is the correct configuration though !!! -------------- next part -------------- An HTML attachment was scrubbed... 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