ATS660: External Clock Upgrade

While the ATS660 features low jitter, high reliability 125 MHz and 100 MHz oscillators as sources of the timebase system, there are occasions when ATS660 has to be synchronized to an external clock source. ATS660 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:

Fast External Clock: 1 MHz < fEXT < 125 MHz
Slow External Clock: fEXT < 10 MHz

The active edge of the external clock is software selectable between the rising or falling edge.

10 MHz Reference Clock allows the user to generate the sampling clock based on a 10 MHz reference input. This is useful for RF systems that use a common 10 MHz reference clock. ATS660 uses an on-board PLL to generate the high frequency clock. Clock frequencies in the range of 110 MHz to 130 MHz can be generated with a 1 MHz resolution.

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  • Provides 3 modes of External clocking:
    • Fast External Clock
    • Slow External Clock
    • 10 MHz Reference Clock

Powerful Slow External Clock

ATS660 uses ADC converters that cannot operate below 1 MHz clock frequency. For customers who have clocks that are slower than 1 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.