Hi, ge,thank you for your answer, the temperature coefficient is a problem. In the schematic simulation, I've found that a temperature drift of only 0.015 degree may lead to a frequency drift of 15KHz. But, the transceiver is working in full-duplex way in TDD mode. That is, whether it is in receiver mode or transmit mode, the LO didn't stop to work. So, I wondered what RFCMOS said, why the more time slots the packet is composed of, the more power it consumes?
As for what you said, ge, longer time frame gives more time for noise and modulation to add up? As I said above, the lo keeps working in receive/transmit mode. Thus, the time duration of packet counts?