Fig. 6: Oscilloscope measurements from demodulated gigabit backscatter constellations and spectra.

a, The front-end is biased with a BPSK waveform that is pulse-shaped with SRRC pulses. b,c, Plots with the demodulated QPSK constellation (b) and with a 16-QAM constellation, boosting the bit rate to 2 Gbps (c).