PLL with output amplitude proportional or equal to input amplitude

[ricko_uk]

Hi,
just a curiosity,
are there such thing as:
1) a PLL or other device device that produces an output frequency (equal or different from the input one) whose amplitude is equal or proportional to the input signal amplitude?
2) a device whose output frequency is proportional to the input signal amplitude?
Thank you

[MagicSmoker]

That sounds like a V/F converter, not a PLL. These were all the rage in analog design back in the 80's as a precursor (or substitute, really) for ADCs (Analog-to-Digital Converters), because real ADCs were very expensive.