请教关于PSKey ANA_FTRIM问题

yizhonglin86

第一次做蓝牙测试，标准的测试是能够通过，但客户有一个校准的不是很理解，内容如下
Xtal alignment
Purpose:
Compensate the initial frequency tolerance of the Xtal to provide sufficient
frequency accuracy.
Precondition: Connect battery simulator to Bat_P (TP J14) and Bat_N (TP J15)
terminal and apply 3.6V to DUT.
Procedure:
1. Connect Bluetooth test set to RF_Pad and RF_GND
2. Activate continuous TX mode of the DUT via SPI. Command:
TestSetContinuousTxMode(ULONG ulDevID, ULONG ulFrequency, ULONG ulIntPa,
ULONG ulExtPa, LONG lModulat ion) [1]
3. Measure frequency of the RF signal and align the Xtal frequency until the RF
signal frequency is in the target window. Start with trim value 31 (0...63), Start trim
RF frequency = 2441MHz +/-300kHz.  Final RF Limit:  2441 MHz  +/- 2441 Hz
4. Write final value to PSKey ANA_FTRIM (hex 01F6) (write decimal value, range:
0 ... 63 )
5. Power cycle the DUT

这个改变PSKey ANA_FTRIM，后面是看什么测试标准的Initial Carrier的值吗？但是Initial Carrier好像没什么变化，请教这个应该是怎么校准的。