Pulse VCO Help

[Chris MacDonald]

I am trying to create a simple VCO which outputs very narrow pulses
(microsecond range) at wide range of frequencies (0 to 10 khz at
least).  It is not intended as an audio source so extreme stability is
not an issue (it's for an experimental envelope generator).  I have come
up with a circuit that works but I'm hoping there's a simpler way to do
it.

I couldn't get a 555 to adjust over a large enough frequency range so I
turned to the 4046.  (Did I miss something with the 555?)  This has
acceptable range but outputs a square wave (I don't believe there's a
way to change this, true?).  I then had to figure out how to convert a
square wave into a narrow pulse wave.  I ended up connecting a capacitor
in series with the VCO output to get a sloped waveform and then ran the
output of that through an omp-amp buffer and then into a comparator
which is used to generate an adjustable pulse wave output from the
sloped wave input.  A trim pot is used to provide a variable voltage for
the pulse width adjustment.

I tried using a 555 as a monostable to generate a narrow pulse from the
square wave but since the trigger input overrides the threshold input I
couldn't find a way to output pulses which were narrower than the
trigger pulse.

So, what I have now works but my parts count is now up to 3 chips, a
trim pot, a capacitor and some resistors and diodes.  I can't help but
feel this is not the best solution to the problem, does anyone know of a
better way?

Thanks,

-Chris MacDonald