Integrator ?

[SUB320]

Hi,
Just doing the transition to the Airbus 320, and I cannot understand what the integrator is and what/how does it function. Cannot find any information in the FCOM except the quote below.Would appreciate any experienced pilot/engineer on the Airbus fleet to explain .

"With the horizontal stabilizer jammed, control is much easier than it is on a conventional aircraft, because the integrator holds the elevator required to maintain the 1g flight path. The control laws remain normal to touchdown."

Thank you