Hi Too much tuning range is easy enough to fix. Use a pot to set it on frequency and then hook it to the rest of the "stuff" with a fixed resistor. The gotcha would be if the poor thing drifts so much that it *needs* the wide range to stay in lock.
My guess is that you could buy a hundred VCXO's at auction for less than the cost of trying a dozen samples. Bob On Mar 29, 2013, at 11:03 AM, paul swed <[email protected]> wrote: > Indeed thats the problem. The VCO needs to be available grabbing something > from ebays good for me but not you. Also the oscillator does need to be an > integer of 240 Khz and Ideally divide on a separate chain to 1 or 2 Mhz so > it could be multiplied to 5 or 10 Mhz as an example. Though for the d-psk-r > thats not really of interest. A seperate item is that just ahead of the > divide by 4 sine and cosine divide it may want a 50% duty cycle though > thats most likely not true. Right now with 12 Mhz I do get 50% duty cycle. > Could with 9.6 also. > > Also I have as an example some 9.6 Mhz Vectron VCOs (How could you go wrong > its a vectron) and the tuning voltage and range are simply to large. As I > mentioned the homebrew osc is .5V for .1 Hz. The challenge I have with > Digikey and Mouser is figuring out from the info what one to buy. I have no > plans to try and buy 10 different oscillators hoping one hits some target. > > So thats a piece of the puzzle. I did get much of the rcvr into ExpressSCH > last night and will revalidate what I have in the diagram tonight. > Regards and thanks for the coments. > Paul > WB8TSL > > > On Fri, Mar 29, 2013 at 10:16 AM, Bob Camp <[email protected]> wrote: > >> Hi >> >> Silly me to not dig all the way to the bottom of the data sheet …. >> >> Looks like the auction sites may be the better choice. >> >> Bob >> >> On Mar 29, 2013, at 9:35 AM, dlewis6767 <[email protected]> wrote: >> >>> The data sheet indicates the Fox924B is not voltage controllable, wever. >> -Don >>> >>> >>> >>> >>> >>> >>> -----Original Message----- From: Bob Camp >>> Sent: Friday, March 29, 2013 7:37 AM >>> To: Discussion of precise time and frequency measurement >>> Subject: Re: [time-nuts] WWVB d-psk-r update. Seems a reasonable solution >>> >>> Hi >>> >>> There are a variety of VCXO's and TCVCXO's on the Mouser site. Prices >> seem to range from $3 to $10 for the reasonable candidates. >>> >>> >> http://www.mouser.com/ProductDetail/Fox/FOX924B-10000/?qs=sGAEpiMZZMsBj6bBr9Q9afDupvxlfd2QBmF8W0236Ww%3d >>> >>> Is one of the many. It runs at 10 MHz, CMOS output, and actually *is* in >> stock. Price is $6.41 for a single piece. I'm sure that a bit more digging >> could get that down a bit. The auction sites also have similar parts. >>> >>> Bob >>> >>> >>> On Mar 28, 2013, at 9:01 PM, paul swed <[email protected]> wrote: >>> >>>> OK it has been a while and I have promised to share results. In the next >>>> few days I will put whats on paper into a schematic and share. I won't >>>> dwell on all of the stuff from October to now. But several front end >> rcvrs, >>>> and several analog Costas loops were built using MC1496s and another >> using >>>> AD633 multipliers. Various other glue. >>>> Nothing to rave about. >>>> >>>> What I will detail is what I have done with quite common parts. But >> what it >>>> isn't is a kit or absolute or anything else. It can be made better. >> Don't >>>> doubt that for a second. >>>> So what I do have are 4 pretty simple and reasonable parts of the >> solution. >>>> It really does work even on the east coast. Though MSF can really cause >>>> issues ocasionally. One key part the costas loop is a design I stumbled >>>> across from 1971 designers casebook electronics magazine ca herbst. Was >>>> cleaning out old papers. The article left a lot of detail out. But the >>>> principle is solid. It was surprising at how well it worked the first >> time. >>>> So what I will share with the Time-nuts are the following schematics. >>>> >>>> A 60 KHz TRF receiver. Takes a 1uv signal and increases it to 2-4 V PP >> with >>>> AGC and soft limiter. It includes a 60 Khz xtal filter to set the >> passband >>>> and a tuned stage or 2. There are quite a few possibilities on the >>>> internet. Tried a few. This is my version. But others would work just as >>>> well. >>>> >>>> Digital costas loop using nothing more the a 74hc86 quad exclusive or. >>>> Resistors and caps to integrate. >>>> >>>> The 12 Mhz VCO. Why 12? Thats the crystals I have. Boy can this area use >>>> some help. >>>> >>>> The divider. Cmos 12 Mhz to 0 and 90 degrees at 60 Khz. This is straight >>>> out of any digital application manual. No magic at all. >>>> >>>> When combined this creates a complete WWVB costas loop solution that >>>> delivers a 60 Khz output locked to wwvb without the phase modulation. A >>>> byproduct is the digital data from the new signal. Not used. Not even to >>>> drive a led. >>>> >>>> A path could be added that literally inverts or not the original AM >> signal >>>> so that spectracom 8170s and Truetime DC60s would work and recover time >>>> correctly. That is a piece O cake. >>>> >>>> So I will get this into a schematic to share over the next day or two. >>>> By the way on performance the system handles sun rise and sets and keeps >>>> ticking. Using a fluke 207 driven by a Rb ref to watch for failures. >> This >>>> is recorded on a 4 channel chart recorder program on a laptop. I have >> used >>>> the system to drive 2 X HP VLF 117s and they track as w >>>> Lots of areas that might be improved AGC control and time constants. >> Adding >>>> a opamp to the 0 degree phase VCO control voltage and also adjusting >> Time >>>> constants. Though the 12 Mhz oscillator is really standard parts just >> could >>>> not find something reasonable and off the shelf. Digikey or Mouser >> stuff. >>>> something with 4 pins and a few $. By the way the control voltage is >>>> .5V/.1Hz. >>>> >>>> Regards >>>> Paul >>>> WB8TSL >>>> _______________________________________________ >>>> time-nuts mailing list -- [email protected] >>>> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>> >>> _______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> _______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
