[time-nuts] Unified VCXO Carrier Board
Charles Steinmetz
csteinmetz at yandex.com
Sun Oct 25 13:21:02 UTC 2015
I wrote:
>>According to the simulation, the resistor has no effect on the output
>>amplitude until it is well below 1k ohms
Bruce replied:
>even 10k increases the output signal amplitude by 130mV or 2.6%.
>However that is smaller than the tilt/sag in the high level output due to
>feedthrough via Cbe of the input transistor when it is off.
Bruce is correct, although I don't consider 130mV to be a significant
effect on a 5v logic level. My fault, I guess, for saying "no"
effect instead of "no significant" or "no material" effect.
But, do we really need to dispute every insignificant, niggling
little detail like this? Even in science, there must be *some*
allowance for the use of everyday language instead of requiring
absolute explicit clarification of every possible point, or all
communications would be unbearably tedious from all of the
qualifications. I say this as someone who is often criticized for
overclarifying to the point of being pedantic and tedious.
There was simply no need, nor excuse, for the prior (incorrect)
suggestion that a resistor to ground from Point "A" would not be
effective in canceling the small asymmetry of the circuit, OR for the
suggestion that such a resistor would be a useful means to adjust the
output amplitude (this because of (i) the concomitant ill effect on
symmetry and (ii) the much more direct and efficacious means of
achieving the result by adjusting R6 or R1 and R2).
Best regards,
Charles
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