Troble with crystal oscillator
I have problem about crystal oscillator related to NE/SA615 receiver.
When worked at 45 MHz it needed 44.454 Mhz crystal from 45Mhz - 455 Khz = 44.454 Mhz
But when I worked at fix frecuency at 38.9 Mhz crystal must be = 38.455 Mhz which I didn't found. the value from 38.9 Mhz-455 Khz = 38.445 Mhz.
Is there crystal at that frecuency..I needed crystal..
Any infomation for crystal?
Thank you
Jeckson
Hi,
You must search for XTAL producers/distributors; they are happy if you will order a relative special frequency, but you must pay for that_often 10-20 time more as for mass produced exemplares ...
One possibility: http://www.wdi.ag/de/quarzfinder_crystal.shtml
Otherweise ask pls the IC seller/prepresentant, maybe they knows some good searches in your region...
K.
THank Karenz
How's about using 3rd harmonic crystal..?
Is that all 3 harmonics frecuencies could be used? Don't know how's 3rd crystal work.
Regards
Jeckson
I guess, that the application circuit is designed for a 3rd overtone crystal, using L2 to prevent oscillation at the fundamental.
It can be expected to work for most 3rd overtone devices, but you should check the final circuit operation and possibly adjust L2 value.
Hi Jeckson,
I checked the NE615 datasheet; they are spoken over a X1=44.545MHz Crystal ICM4712701!
So a quartz is = (as I found it out) a product of "Icmfg": http://www.icmfg.com/ifcrystals.html
K.
Thank's Karenz
For 38.445 Mhz....
Thank you
Jeckson
PS:
FvM
Is nearby crystal possible?[/quote]
Tnx Jeckson!
A nearby XTAL means some another (nearby) receiving frequency by the same IF frequency, or even some another (nearby) IF frequency (if your filter are usable for that-its a real luck) for the same receiving frequency...
K.
Honestly I didn't found solution.
I needed 38.445 Mhz crystal.
If that didn't availbel maybe the 3rd overtone..like 12.815 mhz or else.
Needed advice.
Regards
Jeckson
12.815 MHz crystal is not easy to get.
But a very common and cheap crystal (coming in a lot of packages) is 12.8 MHz.
http://parts.digikey.com/1/parts/393...-10-1-u-t.html
If you get some, is possible when placing a trim capacitor in series with the crystal to change the oscillation frequency up to 12.815 MHz, and multiply by 3 after that. A Buttler configuration is most suitable for this.