Analog Devices, Inc. (ADI) has introduced a 16-channel, mixed-signal front-end (MxFE) digitizer aimed for use in such aerospace and defence applications, including phased array radars, electronic warfare (EW), and ground-based satellite communications (SATCOM) (satellite communications). The new digitizer includes four AD9081 or four AD9082 software-defined, direct RF sampling transceivers. It is designed to accelerate customer product development by providing reference RF signal chains, software architectures, power supply designs, and application example code. ADI also introduced a digitizing card to complement the platform and facilitate system-level calibration algorithms and demonstration of power-up phase determinism.
This system-level calibration algorithm is presently achieved in MATLAB® and takes approximately three seconds to complete. However, if implemented in a hardware description language (HDL), this calibration time may be further reduced while maintaining a completely self-contained algorithm. Additionally, by relying on the MCS algorithms, if the system frequency and amplitude are known at boot-up, users can load phase offset values from a lookup table instead of needing to undergo the measurements described in this system-level calibration method. In this case, the system-level calibration method can be used to populate the phase offsets saved to a lookup table during factory calibration.
A successful MCS process has been demonstrated using four Analog Devices’ AD9081 MxFE™ ICs as the backbone of the subarray. Thermal gradients across the platform are compensated with the aid of phase adjust blocks within four ADF4371 PLL synthesizers.
An HMC7043 clock IC is used to distribute the SYSREFs and BBP clocks required for the JESD204C interface. MCS algorithms within the AD9081 allow for simplified system-level calibrations and provide a power-up deterministic phase for multiple frequencies and thermal gradients present in the system.
An efficient system-level calibration algorithm is also presented that is used to populate LUTs during factory calibration, and therefore dramatically reduces system boot time. This platform is shown in Figure 11 below and is called the Quad-MxFE.
The system is available for purchase from Arrow Electronics Australia. This work is pertinent to any multichannel system present in any phased array radar, electronic warfare, instrumentation, or 5G platform.