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

[Dave hartzell]

Today I have been trying to drive a 5370B directly from a TADD-2, with
little luck (other HP freq counters seem to work OK).   I was about to ask
about it on this list, but noticed this thread.

I guess this could explain why I am getting erroneous, random readings?

Dave



On Sat, Feb 27, 2010 at 4:01 PM, Bruce Griffiths <bruce.griffiths at xtra.co.nz
> 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
>
>
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