High Dynamic Range – or HDR-electronics includes circuits for processing analog signals with a dynamic range far beyond the range of ADC -converters at RF-frequencies. With HDR- frontends we can receive weak RF-signals as low as nano-Volts and generate Watts of real RF-power on the same antenna, in the same time-slot, in the same frequency-range.
Examples are: long-range RFID-readers, single-antenna EAS-detectionsystems, MRI-scanners and inductive metal position-sensors. Dynamic range is 140 dB or more, which can be handled only by a high-speed ADC of 24 bits resolution.
With HDR -frontends the demands on the ADC can be reduced to lower range and or lower bandwidth.
In HDR-electronics, The first stage of the signal-processing where high bandwidth and resolution are required, is done with pure analog components, like amplifiers, mixers and filters. Ultra-low signal events are only limited by thermal noise, without interference of the power-signals.
The power-electronics involved (supplies, transmitters, generators) should be very clean, with low amplitude- and low phase-noise. Many short-range NFC-frontends can be upgraded to long-range RFID by eliminating these noise-sources.
Other sources of interference are prevented by proper EMC-design, and various canceling techniques.