Tim Thanks. I swear that Gerald said the current VF part was sine wave output. I saw the posts about the Greenray a while back and just don't know. This is the first time in my searches that I found a 200 mhz VC part which is available without horrific lead times and no quantity one. If the Crystek part will work in our external closed loop design to drive the SDR accurately then I'm for giving it a shot. That price is not bad either. At times I had seen $80 + parts and they were not low phase noise, or voltage controlled, just +/- 25 ppm TC parts. Although this is a 50 ppm part I think that I saw it could be pulled +/- 500 ppm.
Thanks for the response. Comments? Eric2 -----Original Message----- From: Tim Ellison [mailto:[EMAIL PROTECTED] Sent: Saturday, January 07, 2006 10:32 PM To: Eric Ellison; John Ackermann N8UR Cc: [EMAIL PROTECTED]; FlexRadio@flex-radio.biz Subject: RE: [Flexradio] DIP OCXO for SDR Eric, The VF VCXO listed below has a max frequency at 200 MHz. The XO currently in use, the VF 161 has a max frequency of 300 MHz. Using a device at either end of its rated frequency may suffer from precision and/or accuracy errors. The Crystek is much closer, but the output is a sine wave rather than PECL(positive emitter coupled logic) which is the output of the current XO. I am not sure if this will make a difference or not with the devices being designed. I did find this VCXO that is very close to the VP161 from Greenray, but I received some less than satisfactory comments about the company http://greenrayindustries.com/library/ZT620.pdf -Tim --- Tim Ellison ( [EMAIL PROTECTED] ) Integrated Technical Services ( http://www.itsco.com ) -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Eric Ellison Sent: Saturday, January 07, 2006 9:01 PM To: 'Eric Ellison'; 'John Ackermann N8UR' Cc: [EMAIL PROTECTED]; FlexRadio@flex-radio.biz Subject: Re: [Flexradio] DIP OCXO for SDR John (and others on this thread) Magnus - SM4RWI mailed me off list of a Valpey Fisher 200 VCXO offering with low phase noise. The VF 960/961. I could not find any ready sources for this part and did not request sample or quote. However, it is a pretty nice piece. http://www.mfelectronics.com/products/vcxo/ I decided to go back out and do my occasional search for an available part with low phase noise and 200 mhz VC. Newark is supplying a Crystek 200 mhz VCXO in stock for about $45 Dip and $58 smt. See PDF. http://www.crystek.com/spec-sheets/CCO-083_085.pdf http://www.mouser.com/catalog/624/656.pdf If we are talking about temp stabilizing and disciplining external to the radio, these might be good considerations for the conventional (not computer or FPGA aided) GPS - 10 mhz phase locking system. Someone could take a look and see if the specs are acceptable. Eric2 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Eric Ellison Sent: Friday, January 06, 2006 4:17 PM To: 'John Ackermann N8UR' Cc: [EMAIL PROTECTED]; FlexRadio@flex-radio.biz Subject: Re: [Flexradio] DIP OCXO for SDR John Yes! Gerald HAS really moved a lot of lives with something that actually works, is available, and works very well! It sure has spawned a LOT of interesting projects and experimentation. I agree totally that we should 'brainstorm' a solution for getting the 200 mhz off or on, or around, and or back into the SDR-1000. Something fairly flexible and not too difficult to accomplish. I don't think that any of this is in conflict with others, and nothing is really 'fractionating' the mass of folks in spite of 'parallel' projects going on. If anything we are getting some crosspollination. At this point having gone about as far as we can go with ECO's in this hardware, we are just 'branching out' into associated areas, where former focus was investigating how to directly improve the SDR-1000. Any comments from readers as to how we actually pull the VF osc, buffer it? Parts? Schematics? Block diagrams. Designs (not talk!). Thanks Eric2 -----Original Message----- From: John Ackermann N8UR [mailto:[EMAIL PROTECTED] Sent: Friday, January 06, 2006 9:16 AM To: Eric Ellison Cc: [EMAIL PROTECTED]; FlexRadio@flex-radio.biz Subject: Re: [Flexradio] DIP OCXO for SDR Eric Ellison wrote: [ everything trimmed ] It sounds like there are several groups doing a lot of interesting things with FGPAs that extend way beyond just frequency stability. I think that's really great, and thank Gerald for creating such a great base for creative people to play. From my (and TAPR's) perspective, we want to do a Reflock-based design because it will have a broader use than just the SDR-1000. For example, with a 64MHz VCXO, it can work with the Ettus Research USRP software radio. I can also see it serving as an external clock for a sound card to eliminate that source of frequency uncertainty. So, I don't see any conflict at all between what we're doing and the other approaches. The one SDR1k specific item I'd like to see, whether TAPR produces it or Gerald does, is a "civilized" board that will plug into the reference oscillator socket to allow a better interface to an external signal. I've started looking into that and we'll work with Gerald to figure out how best to offer that. It's mainly a matter of finding a buffer/level converter chip that will take a single-ended input and convert it to a differential signal at the right level for the DDS chip (suggestions welcome; I've started researching the chipmaker sites, but haven't found an obvious answer yet). 73, John _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz
