You're right of course Jean-Paul, thanks. I did want to make him aware that clock multipliers might not be the=20 answer, thus potentially preventing him from spending lots of time=20 investigating them. David, how about a few more words regarding your $ budget, size, quality=20 of the needed signal, stability needed, frequency agility needed, your=20 power budget etc? It would be most helpful. 73 AG On 10/12/2015 07:12 PM, Jean-Paul Louis wrote: > Art, > > You are assuming a lot about the specs needed. David did not tell us > anything about the specs beside the frequency range, and the approximate > waveform (square). He did not give any clue about the application either. > > So far, the SI5351 meet the known specs. > > Let David tell us more before entering a contest on Jitter, Phase noise > and agility. > > 73 de Jean-Paul, > AC9GH > > >> On Oct 12, 2015, at 5:33 PM, Art wrote: >> >> Avoid clock generators if you need low phase noise. They have VERY bad >> jitter. They work by running 2 PLL's, each with different divide by N to >> give the desired output frequency. They operate in the microwave region, >> then divide down to get the lower desired frequency. The problem is that >> you are left with very poor phase noise and jitter. >> >> If you can tolerate noise on the output and timing that isn't consistent >> between each successive pulse, then they are viable. When used as a >> local oscillator for a software defined radio, they bite bigtime, which >> is exactly WHAT I TRIED TO DO:) >> >> For frequency agility, the output is disabled for even a small frequency >> change because both PLL's have to be reprogrammed by your controller and >> you don't get a usable output until both loops are stable. >> >> GL >> >> AG >> >> >> >> On 10/12/2015 04:29 PM, Jean-Paul Louis wrote: >>> Hi David, >>> >>> You should look at the Adafruit module below, >>> >>> http://www.adafruit.com/product/2045 >>> >>> Inexpensive clock generator from 8 kHz to 160MHz. Add a divide by 8 >>> and you get 1kHz to 20MHz. >>> >>> Regards, >>> Jean-Paul >>> AC9GH >>> >>> >>> >>> >>> >>>> On Oct 11, 2015, at 2:04 PM, David C Brown wrote: >>>> >>>> I am looking for a module to generate logic level square wave up to at >>>> least 20MHz (50 would be better) within a $100 budget. There are a nu= mber >>>> of items on eBay but none have them seem to have a proper spec. Any >>>> recommendations from experience? >>>> >>>> --=20 >>>> __________________________________________ >>>> David C Brown >>>> 43 Bings Road >>>> Whaley Bridge >>>> High Peak Phone: 01663 733236 >>>> Derbyshire eMail: dcb.home@gmail.com >>>> SK23 7ND web: www.bings-knowle.co.uk/dcb >>>> >>>> --=20 >>>> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >>>> View/change your membership options at >>>> http://mailman.mit.edu/mailman/listinfo/piclist >> --=20 >> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .