[time-nuts] Achieving maximum performance when driving 5370A/B inputs

[Bruce Griffiths]

Oops! a small correction (2nd paragraph):

For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum.
An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance).
An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance).

For the 5370B attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum.
An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance).
An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance).

Thus using the PPS output (~270 ohm is series with a 5V 74AC04 output) from a Synergy evaluation board that uses an M12M or M12+ GPS timing receiver to drive the inputs (with a 0-750mV signal) of a 5370A or 5370B is well within the recommended input signal range for high performance.
This avoids having to adding an external 5V 50 ohm driver that some would use.

Bruce

Bob Camp wrote:
> Hi
>
> So exactly how did you know that I bought a (cheap) 5370B a few hours ago on the e-place  and was just about to ask about how best to use it.
>
> Hmmmm.......
>
> Bob
>
>
> On Feb 27, 2010, at 7:01 PM, Bruce Griffiths wrote:
>
>    
>> The attached excerpts from the 5370A and 5370B manuals indicate that for best performance, that the common practice of driving the 5370A/B 1x inputs directly from a 5V CMOS logic signal is a bad idea.
>>
>> For the 5370A attenuating the 5V CMOS signal to a 1V swing with the threshold set to 0.5V is close to optimum.
>> An input signal with limits of 0V and +1.4V with a trigger threshold of 0.7V is the maximum usable (for high performance).
>> An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance).
>>
>> For the 5370A attenuating the 5V CMOS signal to a 2V swing with the threshold set to 1V is close to optimum.
>> An input signal with limits of 0V and +3.5V with a trigger threshold of 0.7V is the maximum usable (for high performance).
>> An input signal with limits of 0V and +0.3V with a trigger threshold of 0.15V is the minimum usable (for high performance).
>>
>> Bruce
>>
>> <5370ATriggering.png><5370BTriggering.png>_______________________________________________
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