hi josh, we usually inject the 1 PPS "sync signal" into the SMA sync input on one of the casper adc boards, which plugs into the roach2.
however, as you point out, you can also inject sync directly into the J10 SMA input on the roach2. J10 is DC coupled, and set up to receive a 1 PPS signal. we typically use (for either ADC sync, or roach2) a standard 1 PPS pulse distribution box that has a 50 ohm output impedance and delivers a 0 to 2.5 volt pulse when it's output is terminated in 50 ohms (both the roach2 and and adc board sync inputs terminate in 50 ohms). (note: this is 0 to 5 volts if you don't terminate the output). have fun with 1 PPS, dan On Wed, Aug 6, 2014 at 2:08 PM, Josh Sypherd <[email protected]> wrote: > Hi everyone, > For the sync input on the ROACH 2 GPIO the CASPER website says that it > requires a pulse per second, but we are unsure what amplitude, pulse width, > ect. we need for it to function. > Thanks, > Josh >
