By default, the correlator keeps time by generating clock ticks every tenth of a second. If you specify the –Xclock option when you start a correlator, the correlator disables its internal clock. This means the correlator does not generate clock ticks and does not assign timestamps to incoming events.

Instead, it is up to you to send &TIME events into the correlator to externally keep time. This gives you the ability to artificially control how the correlator keeps time.