Eml synthesizers

There are various waveforms and corresponding circuits that
produce them. I want to learn the structure of the circuits
that create the most large and fundamental alterations to
the waveforms, namely:
circuits that vary the amplitude of the peak of the
waveform relative to the progression of a sine wave from
the initial part of the waveform, and circuits that vary
the wavelength of the end of the waveform relative to the
progression of a sine wave from the peak of the waveform.
It may be possible to simultaneously create increases in
both parameters or decreases in both parameters with a
single circuit component, but I'm not sure. I am looking
for an analog circuit that performs these functions
smoothly, as opposed to a digital circuit that performs
them abruptly and produces resulting harsh sounds, although
it may be possible to easily convert any such digital
circuits into analog circuits by substituting certain
parts. It is my guess that such circuits implement voltage
control, and utilize analog field-effect transistors, but
I'm not sure. I want to know the specific complete stucture
of such circuits though, not just the very most basic
characteristics. I ask that someone give me a link to the
schematics of such circuits or a link to a description of
the schematics of such circuits, or reply to me with a
crude text drawing of such schematics, or reply describing
the schematics with words.
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