For example setup, I use:
- set TX frequency to 2400.0 MHz
- set RX frequency to 2399.9 MHz
- set sample rate to 1 MHz
- setup gains, antennas, etc (BAND2, LNAH)
- enable on-board (not on-chip!) channel loopback
- run FFT
- run different signals. Single tone is built-in into LimeSuite, zero signal is 2048 bytes long file filled with zero bytes.
Observe level at +100 KHz on the receiver.
External high quality spectrum analyzer shows basically the same picture of this spike-to-noise relation.