Emulating a temp sensor

This could be ridiculously basic but can i emulate a LM35 temp sensor by using a suitably rated resistor between the 5v pin and an analog pin?

For example dropping the voltage to 300mV to emulate a 30C temperature

not with just one resistor, you will need a 3 wire pot to do that. The outer ones go to 5V and ground, and the center goes to you analog input. Or you could make a voltage divider with several resistors in series and take the different voltage drops between the resistors to use as a simulation.

The concepts on the following WIKI are what you are after...