The Chirp is called a Talk Permit Tone, and the only thing that tells us is that he was on a Trunked system. It doesn't tell us whether he was using encryption or not. The only way for a radio user (not scanner) to see if he is using encryption is to look at the radio's display or check the position of a button or switch. What the chirp technically means is that his radio, after sending a Request to Talk signal, has been issued a channel grant (been assigned a frequency to use) and he can now start talking.
"People are weird." --Captain Don Cragen