More compact ways to avoid collisions and isolate electronics
Chip manufacturer Analog Devices Inc. had two interesting demos that illustrate state-of-the-art unmanned systems electronics work. The first was a reference design for a 24 GHz radar transceiver chipset as used for automotive collision avoidance systems (top). It has four receiver channels for detecting multiple objects as small as 15 cm in diameter and sitting up to 200 m away. The receiver/downconverter chip is an ADF5904. Other chips involved include a ramp generator, DSP, VCO, and a radar signal conditioning chip containing a low noise preamp with a programmable gain amp and an antialiasing filter in each channel plus one direct-to-ADC channel. A claim to fame of the design is a low noise floor which lets the system detect relatively small targets.
Another demo (bottom) showed digital isolation. This is basically a means of galvanic isolation that doesn’t use optocouplers, which tend to consume a lot of power and are generally limited to a speeds of a few megahertz. Instead, Analog’s SPIsolator chips use chip-scale transformer technology for isolation. The technique is said to provide a low propagation delay and jitter in the CLK, MO/SI, MI/SO, and SS serial peripheral interface bus signals and supports SPI clock rates of up to 17 MHz.
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