Key rate limit

[tsuraan]

I have a keyboard with a slightly broken "j" key; sometimes, a single
press will result in a bunch of "j" characters all being sent at
nearly the same time.  Is there something I can do with my X
configuration so that all events for the same key appearing in the
same quarter second will be condensed into a single event?  I don't
think I'm capable of deliberately hitting the same key that quickly,
and I think it would effectively solve the problem that I'm having, if
X has some mechanism for doing that.