This section describes, how the filter and PLL calibration algorithms are started manually. The filter calibration algorithm is done automatically, whenever a state change from the states P_ON or SLEEP to the state TRX_OFF occurs or a transceiver reset is performed. The PLL is calibrated during a state change from state TRX_OFF to any of the [PLL_ACTIVE] states. If these state changes does not occur during the normal operation of the radio transceiver frequently every 5 minutes, it is recommended to start it manually within this period. If the operating conditions of the radio transceiver (temperature, voltage) are nearly constant, the recalibration period may be increased.