PLATFORM FIELD GUIDE

[ REALDIGITAL ]

Gen 3 RFSoC on an academic budget

RFSoC 4x2 field guide.

The RFSoC 4x2 puts a Gen 3 RFSoC (four 5 GSPS ADCs and two 9.85 GSPS DACs) on a board priced for universities and research groups, with first-class PYNQ support. It has become the default platform for academic SDR, radio astronomy prototyping, and anyone who needs real direct-RF hardware without a program budget. This guide covers the board, the two ways to develop on it, and how to run it continuously without cooking it.

BOARD RFSoC 4x2RF-ADC 4 × 5 GSPSRF-DAC 2 × 9.85 GSPS
Arm PSA53 ×4 · R5F ×2UltraScale+ PL fabricYOUR DSP LIVES HERERF-ADC · 4 × 5 GSPSRF-DAC · 2 × 9.85 GSPSRF INRF OUTLMK04828 + LMX2594
RFSOC 4X2: CONVERTER FABRIC, TO SCALE IN CHANNELS
[ 01 ]

AT A GLANCE

At a glance.

DEVICE
Zynq UltraScale+ RFSoC ZU48DR (Gen 3)
RF-ADC
4 channels · 14-bit · 5 GSPS (SMA)
RF-DAC
2 channels · 14-bit · 9.85 GSPS (SMA)
CLOCKING
On-board LMK04828 + LMX2594
HIGH-SPEED I/O
QSFP28 cage (up to 100G) · USB 3.0
SOFTWARE
PYNQ image standard; full Vivado/Vitis supported
COMMUNITY
PYNQ + CASPER ecosystems
[ 02 ]

ARCHITECTURE

Architecture in brief.

The ZU48DR carries the same Gen 3 converter technology as the flagship parts; the 4x2 simply bonds out fewer channels and clocks the ADCs at 5 GSPS. Four phase-coherent ADCs is exactly the shape of a direction-finding array, a small interferometer, or a multi-band monitoring receiver, which is why the board shows up in so many research programs.

Development runs on two rails. The PYNQ image gets you from power-on to captured samples in an afternoon: Jupyter notebooks, Python drivers for the data converters and clocks, community overlays. Bare-metal Vivado/Vitis development uses the identical silicon flow as the ZCU111/216, so designs prototyped here migrate up the family with the RF plumbing already understood.

[ 03 ]

BRING-UP

Bring-up: where the time goes.

The 4x2's out-of-box experience is genuinely good, which makes the remaining traps sharper, because they arrive after you think you're done:
SEQUENCE 04 GATESSTEP 01 on-board LMK/LMX lock
01 / 04Clock treeon-board LMK/LMX lock02 / 04RF tilespower-up + configure03 / 04MTSSYSREF alignment04 / 04Coherent I/Qcalibrated capture
SKIP A STEP AND THE FAILURE SHOWS UP TWO STEPS LATER; RUN IT IN ORDER, VERIFY EACH GATE
  1. 01

    Two flows, two mental models

    PYNQ's Python clock and RFDC drivers configure the LMK/LMX parts for you; a custom Vivado design must own that configuration itself. Teams migrating from notebooks to production bitstreams routinely lose a week rediscovering clock programming the image had been doing silently.

  2. 02

    MTS on four channels is still MTS

    Phase coherence across the four ADCs needs the same SYSREF-driven synchronization procedure as the big boards. If your application is DF or beamforming, verify per-channel phase after every cold start, not once.

  3. 03

    Thermals under sustained capture

    The stock heatsink-fan is sized for bench duty cycles. Continuous wideband capture (the radio-astronomy and monitoring use cases) wants managed airflow, which is precisely why we build a 1U enclosure for this board.

  4. 04

    Getting data off the board

    Four ADCs at rate produce far more than USB or 1G Ethernet can carry. Sustained instruments need the QSFP path into the fabric. A 100G streaming pipeline is its own design task, and sizing it early shapes the whole architecture.

[ 04 ]

DEPLOYMENT

Racking it.

Apexia 1U rackmount enclosure for the RealDigital RFSoC 4x2 board
[ COMING SOON ]RACKMOUNT ENCLOSURE

RFSoC 4x2 Enclosure

Research deployments run for months, not minutes. Our 1U rackmount enclosure gives the 4x2 managed airflow for continuous operation, front-panel RF and QSFP access, and a form factor that racks alongside the rest of the instrument.

[ 05 ]

BUILDING ON IT

Building on it.

Our DSP cores target the 4x2 directly (DDC and decimation chains, polyphase channelizers, and MTS-aware coherent ingest), and the CASPER toolflow service covers this board for instrument-scale acquisition work.

For teams building detection or direction-finding systems on the 4x2, the same bench that builds our cores takes on custom firmware, GPU post-processing, and the mechanical/thermal integration around the board.

RFSoC BRING-UP AND DEPLOYMENT

Running aRFSoC 4x2program?

Bring-up, coherent multi-channel capture, DSP cores, and deployment hardware; one bench covers this platform end to end.

PALM BAY, FLORIDA · 28.0345° N 80.5887° W

CLARITY BEYOND THE NOISE