Teledyne e2v offers its EV10AS940, the latest advanced 10-bit broadband data converter. This device forms part of its multi-year push into software-defined microwave technologies and builds upon past reported proof-of-concept work in this demanding and exciting field.
"The EV10AS940 represents a paradigm shift for microwave radio link engineers. For the first time, it is possible to conceive of simple radio designs where frequency planning is entirely abstracted to the digital domain," highlighted Nicolas Chantier, strategic marketing director.
Conventional radio systems are still based on the heterodyne principle, mainly owing to current component bandwidth limitations. Heterodyning is the process of mixing two signal frequencies in a non-linear mixer. For receivers, the lower frequency heterodyne signal lands within the baseband reception range – usually defined by the input bandwidth of an A/D converter.
Moving to high bandwidth, direct conversion devices make it feasible to conceive of greatly simplified, software-defined receivers with frequency agility. This is particularly helpful when managing the substantial parallelism required of beam-steered applications.
Frequency planning, signal demodulation, filtering and front-end design all gain from direct sampling. Furthermore, with a raft of integrated digital assist features, this device improves receiver operation. Four independent numerical controlled oscillators allow agile frequency hopping. A programmable digital down converter offers various decimation intervals (from 1 to 1024). The device connects through license-free ESIstream serial links to FPGA-based signal processing. Also, an easy-to-use, multi-channel synchronisation facility guarantees synchronous sampling across several devices – excellent in phase-sensitive, beam-steered systems.
This sampler institutes a major front-end architectural change. Frequent-dependent baluns can be eliminated by migrating to single-ended design rules for the clock and signal lines. Those components add cost and weight while band-limiting frequency selection. This is a big deal since baluns negatively impact upon dynamic performance and simultaneously prevent multi-band operation.