They dont emulate, they tune the transistor properties to get the required resistance or capacitance. Its pretty wild. They could use inbuilt caps and resistors

They dont emulate, they tune the transistor properties to get the required resistance or capacitance. Its pretty wild. They could use inbuilt caps and resistors, but, theres no need when tuning a transistor value yields the same result. Iirc, the capacitance is dealt with by the gap distance of transistors, resistance by the lead