BladeRF2 Micro XA4 Heating Effect

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TobyXue
Posts: 3
Joined: Thu Sep 15, 2022 12:04 pm

BladeRF2 Micro XA4 Heating Effect

Post by TobyXue »

Hello,

I attempted to utilize the BladeRF SDR for signal power measurement. My approach involved connecting the signal generator directly to BladeRF's RX 1, using a sinusoidal wave at 400 MHz with a power level of -35 dBm. MATLAB was employed to control the SDR, and the signal power was calculated using the formula: rms(x)^2. After 1 hour of measurement, a significant deviation was observed between the final and initial measurement results (refer to Figure 1, Iteration number: 1 iteration is equivalent to 2s ). Figure 2 illustrates the temperature readings from the internal temperature sensor of the SDR.

After approximately 1 hour of measurement, I incrementally increased the input power levels from the signal generator to -25 dBm and -20 dBm, respectively. The deviation exhibited a linear increase corresponding to the rise in input power.

My inquiry is as follows: Is this deviation normal, and what could be the reason for the substantial deviation attributed to heating effect

Please note: the AGC was set to manual mode and the gain was always 0 dB at Rx1.

Thank you.

Figure 1:
Image

Figure 2:

Image
robert.ghilduta
Posts: 156
Joined: Thu Feb 28, 2013 11:14 pm

Re: BladeRF2 Micro XA4 Heating Effect

Post by robert.ghilduta »

This was resolved via email. For posterity's sake: it appears having a CW on top of or way too close to the LO causes the AD9361's builtin DC offset calibration to try to remove the over the air signal. The solution is to move the CW away from the LO.
misixo
Posts: 1
Joined: Mon Jan 22, 2024 8:33 pm

Re: BladeRF2 Micro XA4 Heating Effect

Post by misixo »

robert.ghilduta wrote: Tue Jan 09, 2024 4:04 am This was resolved via email. For posterity's sake: it appears having a CW on top of or way too close to the LO causes the AD9361's builtin DC offset calibration to try to remove the over the air signal. The solution is to move the CW away from the LO. drift boss
That can solve how long it takes to maintain
tynsaras
Posts: 1
Joined: Thu Feb 01, 2024 12:51 am

Re: BladeRF2 Micro XA4 Heating Effect

Post by tynsaras »

Okay, managed to solve this by manual uploading of the FPGA from python and not installing the auto FPGA loader.
bekean
Posts: 3
Joined: Mon Feb 19, 2024 7:42 pm

Re: BladeRF2 Micro XA4 Heating Effect

Post by bekean »

Although you mentioned that the AGC was set to manual mode and the gain was fixed at 0 dB drift hunters it's worth double-checking that there are no unintended changes in gain or AGC behavior during the measurement. Automatic gain control can introduce variations if not properly controlled.
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