Here is datasheet https://pira.cz/pdf/TSA5512.pdf and it says "The TSA5512 is a single chip PLL frequency synthesizer
designed for TV tuning systems."
But from what I can see it's just PLL, and requires external crystal and puts out voltage according to phase difference between crystal oscillator and RF in.
If I understood correctly, TSA5512 doesn't put out signal from its oscillator.
TSA5512 don't have an internal VCO, and needs an external one.
The external VCO is controlled by the phase detector (PD output of the chip).
The 4MHz internal oscillator is the Reference oscillator.