JR I checked out the PIC VFO Controller and the SDR circuit that Cecil posted here yesterday by Expanded Spectrum Systems; Time Machine TM1. And I got your NE602 Splitter diagram for 455 kHz. I'll redo the DRM convertor now with that splitter for a QSD idea and give your data on the recommended core and turns for that.
"I would consider using a wideband transformer as the splitter .. about 12 turns trifilar on a FT37-77 core should be about right for a 602 at that frequency." "JR" <http://www.ik3oil.it/_private/article%20FLL%20VFO.PDF> Anyone have a link for software to go with the PIC VFO Controler? <http://www.hpsdr.com/Public/Parts/Clock/TMschematic.pdf> Time Machine TM1 SDR "Transceiver" If one took one of the above VFO's and combine it with the TM1 Transceiver circuit then that could make a complete PC controlled SDR radio. I have a software here that controls all of National Semiconductors Phase Lock Loop Chips. It is kind of funky looking but is a designer platform and it is very simple. It also shows you how to connect the IC to the back of the PC. It is not much on Kilo Bytes so I will upload it for folk to use as soon as I can. That could be the basis of someone doing some work with those chips and coming up with a neat software to run a PLL in a receiver. The Phase Look Loops it runs comes in some GHz range models. The TM1 uses the passive TUF1 mixer chips as the detector section. The audio appears for the moment to be via two op amps(?) MAX 410. It also appears to have a phase shifted transmitter section in the circuitry using again, two TUF1 ICs. The transmitter appears simple and appears to be minimal and looks like it is meant to be followed by some gain sections to the antenna. It seems like an interesting idea all in all. It looks like a very cool circuit. I am keeping this diagram. <http://www.hpsdr.com/Public/Parts/Clock/TMschematic.pdf> I have noticed that quite a few folk are now working on various circuitry ideas here at this group so soon we might start to see some of them emerge as kits here and there. As Cecil made a comment on in regards to the receiver manufactures recent interest in the H&P ideas, I think the desired future movement in SDR circuits is to get rid of the spurs and so they are seriously looking at that. The PIC Controler idea currently might be that ticket for them if they want to research it in their design and engineering labs and hence futher it. <http://www.ik3oil.it/_private/article%20FLL%20VFO.PDF> I have an idea for Alberto to try. He might make Winrad and SDRadio able to display any center frequency you want by entering into it the disired display range such as it showing 455 kHz or 10.7 MHz as well as the current 7050.00 kHz. Sort of an user option. That then would make it very useful no matter what the direct conversion frequency scheme was. Dan _____________________________________________________________________ PrivatePhone - FREE telephone number & voicemail. A number so private, you can make it public. http://www.privatephone.com [Non-text portions of this message have been removed] Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/soft_radio/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/soft_radio/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
