I'm building a clock distribution network using a 10Mhz Rubidium standard as an input signal. The signal is a sine wave (1.5Vpp). The other instruments (that should be provided with this clock reference) require a square input as provided by the circuit. I tried to simply feed the sine signal into the PRI_INP port and got a square output. Unfortunately this only holds true for low supply voltages of up to 1.8V, above that the board does not output a signal at all. In addition the output signal shows non-square like artifacts for all voltages. Hence I'm wondering why I do not observe an output signal above 1.8V (square turns into dirac pulse and vanishes ) and whether the output signal is reliable in terms of frequency and jitter. In other words: can I reliably the circuit board for my particular task below the somewhat arbitrary 1.8V?