A first stage PLL and a /2 divider can give you the 2X
frequency to make 0, 90, 180, 270 degree phase-field
with a 2-bit counter behind it. But you might have to
step away from the crusty old CD4046 to something
with a <5um gate length. Look at "older" (like only 10
years old) PLLs from the first couple of wireless
generations, these will handle GHz and if you direct-drive
the input with logic, (rather than a capacitor-blocked
small signal RD sine wave) you have no minimum frequency.
This does however demand a high gain and clipping, to
get there from a small signal-under-test.