Remote testing gives RF engineers a short-cut to mmWave application development
The adoption of millimeter wave (mmWave) technology is accelerating. It is already strong in military and aerospace applications, but the increased exploration of low earth orbit space and, of course, the ongoing roll out of 5G cellular networks is increasing design momentum. The use of extremely high frequency (EHF) bands for license-free wireless communication is also an active application area.
It is well known and accepted that radio frequency (RF) design is complex, but moving into the mmWave domain compounds this complexity. Experienced RF engineers are sought after, but so are the solutions that can help minimize complexity and accelerate the design cycle.
The traditional design cycle begins with circuit development, schematic capture and PCB layout, stalling further progress until the hardware is available. Once ready, it must then be tested and validated before any firmware or software development can begin. That typically requires a board support package and associated protocols. The result is a lengthy, complex and costly upfront investment before any return can be realized.
It is also understood that the test equipment needed to work in the EHF part of the spectrum is highly specialized and expensive. It can easily cost over $1 million to fully equip an engineer’s development bench for mmWave design. Access to the test equipment will be limited, with demand coming from across the design department and possibly the entire engineering division.
This all points toward a need for improved high-level design support and easier access to test equipment capable of supporting EHF development. Fortunately, Avnet understands this and has worked closely with its partners Xilinx, Rohde & Schwarz and MathWorks to create a solution.
It comprises the Xilinx RFSoC Gen 3 kit for mmWave design, a native MATLAB application called the Avnet RFSoC Explorer® and a mmWave test lab provided by Rohde & Schwarz. Uniquely, the test equipment and mmWave board are co-located, remotely, and accessed over a secure LAN connection using the Avnet RFSoC Explorer application. This makes the hardware and test equipment available to any engineer anywhere in the world at any time.
Engineers can now remotely access mmWave RF test equipment through the Rohde & Schwarz Secure Application Gateway™. The Avnet mmWave Radio Development kit based on the Xilinx Zynq RFSoC and all the test equipment can be accessed and controlled from anywhere in the world. (Source: Rohde & Schwarz)
Secure, remote testing
Using platforms to accelerate design cycles is not new. They provide a solid foundation on which to rapidly build expertise and differentiated technology. In the mmW domain, the availability of these platforms is still limited.
The monolithically integrated Xilinx Zynq UltraScale+ RFSoC features hardware blocks specifically designed for RF applications, which include analog-to-digital converters able to sample at 5 giga-samples per second (gsps) and digital-to-analog converters that can sample at up to 10 gsps. This means it can operate as the baseband processor for the system, able to generate waveforms up to intermediate frequencies. Other pertinent features include a soft-decision forward error correction engine, a quad-core Arm Cortex-A53 processor and a dual-core Arm Corte R5 real-time processor.
The Avnet mmWave radio development kit combines the Xilinx RFSoC with a dual transceiver mmWave RF front-end daughter card based on technology from Otava. This provides up/down conversion to/from mmWave carriers between 19 and 31 GHz.
Avnet RFSoC Explorer runs on your local computer, giving you access to the Radio Development kit and test equipment remotely over a secure connection. (Source: Avnet)
The equipment used in the lab supports 5G NR measurements and includes the R&S®FSW and R&S®FSV3-K147 high-end signal and spectrum analyzers, the SMW200A Vector Signal Generator and the SMA100B RF and Microwave Signal Generator.
The Avnet RFSoC Explorer app includes the 5G ToolBox from MathWorks, which can be used to generate a 3GPP-compliant 5G NR test waveform. This signal is mixed up to 27.9 GHz and fed into the spectrum analyzer, which is equipped with the 5G NR Measurements option. Using RFSoC Explorer in their own location, engineers can take measurements while having full control over the DSA/LNAs for gain control and PLL settings for the local oscillator.
Automated 5G NR testing demonstration
The Avnet boards and test equipment are all controlled remotely using the Rohde & Schwarz Virtual Instrument Software Architecture (VISA) protocol. This standardized software library allows fast communications over diverse interfaces, with a wide variety of T&M instruments that are detected on the network by applications running on a PC.
Rohde & Schwarz worked with Avnet to develop object-oriented classes in MATLAB using the VISA protocol to enable the test equipment to interface with Avnet RFSoC Explorer and control Avnet’s mmWave Radio Kit, including the Xilinx RFSoC Gen 3 data converters and Otava mmWave signal chain. An application programming interface (API) provides programmatic control of all RF ADC and RF DAC parameters, ADC signal acquisition, DAC signal generation, and streaming data to and from the board and test equipment. The API also supports automated testing through command sequences.
This recorded webinar provides a more detailed explanation of how Avnet, MathWorks, Xilinx and Rohde & Schwarz are working together to bring remote testing to engineers working on mmWave development.
Engineers can now access a ready-to-develop mmWave RF platform and test equipment from anywhere in the world. (Source: Rohde & Schwarz)
Avnet and Rohde & Schwarz will also hold a full-day online workshop on Automated Remote Testing of mmWave RF Systems with Xilinx RFSoC.
