In the FSK mode, when continuously transmitting the modulated wave using RF_TEST_MODE, the center frequency shifts by about 3 KHz.|FAQ|ROHM Semiconductor

FAQ's

In the FSK mode, when continuously transmitting the modulated wave using RF_TEST_MODE, the center frequency shifts by about 3 KHz.
- As described in the data sheet, when using RF_TEST_MODE in FSK mode, the modulator reads unnecessary data before the generation of the expected test data just after TX_ON is started up. Therefore, the center frequency changes. To use RF_TEST_MODE correctly, check again through the following procedure.
  　1. Initialization register setting
  2. Execute VCO_CAL
  3. TX_ON
  4. After starting up TX, MODEM reset
  * Note: Usually, this event does not occur when transmitting packets containing DIO control. So, it is not required to perform a MODEM reset after TX_ON. This is also an event specific to FSK mode. There is no problem in GFSK mode.
  Related Products: ML7344/ML7406 family, ML7345 family, ML7404, ML7414