While the ATS860 features a low jitter, high reliability 250 MHz oscillator as the timebase source, there are occasions when ATS860 has to be synchronized to an external clock source. ATS860 External Clock option provides an SMA input for an external clock signal, which can be a sine wave or LVTTL signal.
In order to operate the ADC under optimal conditions, the user must set the appropriate frequency range for the external clock being supplied. The following ranges are supported:
ATS860 uses ADC converters that cannot operate below 20 MHz clock frequency. For customers who have clocks that are slower than 20 MHz, AlazarTech has designed the powerful Slow External Clock.
Slow External Clock must be a 3.3 Volt LVTTL signal. Sine wave or other types of signals are not allowed.
In this mode, the ADCs run at 125 MHz internal frequency, but the hardware detects a rising (or falling) edge of the incoming Slow External Clock and latches one sample point for each edge. This results in a sampling jitter of ±8 ns, which may or may not be acceptable in a particular application.