Strange RX I/Q Signal

[falkor]

Some days ago I got our BladeRF x115. The module seems to be correctly connected to the PC running Linux, and I can tune to some local transmitters.
However the RX signal (in frequency domain) looked odd. Even with no signal on the antenna, or a 50 Ohms termination connected to the RX input, turning up the amplifiers resulted in pulsating signals all over the captured frequency range.
Switching to osmocom_fft in oscilloscope mode, I got the attached signals. It seems the I and Q input signals are near -1 all the time, and sometimes wrap over to 0. The signal never gets in the positive range. It always keeps between -1 and 0.

Same thing applies if i capture binary data using the bladeRF-cli tool. It also just outputs 16-bit values between 0xF800 and 0xFFFF.

The LMS_RXD11 signal directly at pin 2 of the LMS6002D changes between high and low. So normally the MSB should change in software too, however it seems to get lost somewhere in between the LMS6002D and the PC.

Firmware version is 1.6.1
FPGA version is 0.0.3

Has somebody any idea what may be wrong?

[robert.ghilduta]

Hi Falkor,
That certainly does not look right. Does this happen with both units?
What FPGA version are you using? Running `version` in bladeRF-cli -i should tell you.
Have you tried transmitting anything?