Avoid clock generators if you need low phase noise. They have VERY bad=20 jitter. They work by running 2 PLL's, each with different divide by N to=20 give the desired output frequency. They operate in the microwave region,=20 then divide down to get the lower desired frequency. The problem is that=20 you are left with very poor phase noise and jitter. If you can tolerate noise on the output and timing that isn't consistent=20 between each successive pulse, then they are viable. When used as a=20 local oscillator for a software defined radio, they bite bigtime, which=20 is exactly WHAT I TRIED TO DO:) For frequency agility, the output is disabled for even a small frequency=20 change because both PLL's have to be reprogrammed by your controller and=20 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 numb= er >> 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 .