Anti-jamming performance with low-resolution ADCs.

[tomojitakasu]

The Pocket SDR FE 8CH uses the 2- or 3-bit ADC provided by the MAX2771. To evaluate the anti-jamming performance of the FE 8CH, I conducted simulations with various ADC bit depths. The following figures show the results for 3-bit, 8-bit, and 12-bit ADCs.

In the simulation, I assumed a 7-element co-planar array using the MVDR algorithm for beamforming. The 3-bit ADC achieved 28–38 dB of jammer suppression. However, there is a significant difference compared to the 12-bit ADC, which provides 73–85 dB. Therefore, I plan to design a 12-bit ADC version of the Pocket SDR FE 8CH for anti-jamming applications.

[iceberg1369]

Please share simulation coee here

[tomojitakasu]

Here are the codes. All of the codes are written by Gemini.

sim_anti_jamming.py

[tomojitakasu]

Here is the updated version that reflects the results of GPT and Claude's reviews.

sim_anti_jam_v0.2.py

[ashrafjk73]

Q1. Professor how did you implement planar array in pocketSDR? can we do that for direction finding?
Q2. in https://s-taka.org/en/awesome-pocketsdr-config/ you have mentioned SPIDER hardware for direction of arrival estimation. what is this hardware, i couldnt find search results on internet? Where to get this hardware and how accurate DoA does it give?

[ashrafjk73]

Q3. Professor if we want to use 12 ADC with 8 Ch PocketSDR, how can we do that?
Q.4 When are you planning to roll out your 12 bit ADC version of 8 Ch PocketSDR as you have mentioned above?

[iceberg1369]

I think it should take about 5 monthes

[tomojitakasu]

A1: I'm still working on it. As to H/W, I decided to change from helical antennas to patch antennas for the elements, considering mutual coupling. As for the S/W, ver.0.14 does not support the array yet. I plan to add support in ver.0.15. DOA estimation is an important application of antenna arrays.

A2: The SPIDER is an 8 - 14 CH RF frontend equipped with the MAX2769. The H/W is complete, but S/W development has been halted. Development efforts have shifted to the Pocket SDR. Pocket SDR FE 8CH can be used for anttena-array. However, the FE 8CH with a 2-3 bit ADC has insufficient dynamic range for anti-jamming applications.

A3: Please wait a little longer. The H/W design will be published and included in the Pocket SDR ver.0.15 release.

A4: Targeting spring 2026, but that is just a plan. The H/W development might require significant effort.

[ashrafjk73]

Professor, about point 4, will spring 2026 solution include Receiver Phase coherency as well as 12-bit ADC both? i hope so as both functionalities would be required for developing anti-jam solution and GNSS receiver on the 8-ch pocketSDR

[tomojitakasu]

While phase coherency is essential for antenna arrays, synchronizing eight MAX2771 PLLs is difficult. Therefore, live calibration must be implemented on the software side of the SDR.
Refer also to:
#59

[ashrafjk73]

Professor, i will seek detailed guidance once 8-Ch PocketSDR is available, on how to implement live calibration in software

[ashrafjk73]

Professor, about point 4, will spring 2026 solution include Receiver Phase coherency as well as 12-bit ADC both? i hope so as both functionalities would be required for developing anti-jam solution and GNSS receiver on the 8-ch pocketSDR