Hello,
I have been trying to modulate the device by using I2S data. But I couldn't get the results that I expected. Here is my setup:
840MHz external VCO with about 5KHz loop filter band width.
I2S one frame = 31KHz, Modulation data = 1KHz Sin wave 31KHz sampling, Deviation = 3KHz, FSK step = +17412 at 3KHz deviation
I set modulation/FSK related registers to proper values.
I monitored the RF output signal using a spectrum analyzer and a modulation analyzer, but the RF signal is just CW, no FM modulation at all. The PLL loop filter band width should be wide enough to modulate something. I changed register values to several ways but no luck. I verified that FSK PIN mode works fine.
Am I missing something? Please advise.
NTN