As discussed above, in some embodiments, an interrogator device may comprise a waveform generator configured to generate linear frequency modulated (LFM) RF signals (RF chirps). In some embodiments, a waveform generator may be configured to generate RF chirps using a phase locked loop (PLL). Illustrative examples of such a closed loop approach are described below with reference to FIGS. 13A, 13B, and 13C. It should be appreciated, however, that a waveform generator is not limited to using a PLL to generate RF chirps and, for example, may be configured to use an open-loop (non PLL controlled) oscillator to synthesize RF chirps. It should also be appreciated that a waveform generator is not limited to generating RF chirps and may be configured to generate any other suitable RF signals, including any of the RF signals described herein, as aspects of the technology described herein are not limited in this respect.
FIG. 13A is a block diagram illustrating waveform generator circuitry 1300 configured to generate linear frequency modulated waveforms using a phase locked loop, in accordance with some embodiments of the technology described herein. Waveform generator circuitry 1300 may be part of any waveform generator described herein including, by way of example and not limitation, waveform generators 110, 110b, 110c, and 110d described above with reference to FIGS. 8A-D.
