It should be appreciated that the embodiment illustrated in FIG. 8A is illustrative and that there are variations. For example, in some embodiments, there may be zero, one, two, three, or any other suitable number of amplifiers of any suitable type between any pair of circuits shown in FIG. 8A. As another example, there may be zero, one, two, three, or any other suitable number of filters of any suitable type between any pair of circuits shown in FIG. 8A. As another example, although in the illustrated embodiment ADC 816 is part of transmit and receive circuitry 112a so that digitized waveforms are output from the transmit and receive circuitry 112a to control circuitry 118, in other embodiments ADC 816 may not be part of transmit and receive circuitry 112a and, instead, may be further downstream in the processing chain. In such embodiments, analog waveforms may be output from the transmit and receive circuitry 112a to control circuitry 118.
As described herein, waveform generator 110 may be configured to generate any RF signals of any suitable type including frequency-modulated waveforms, in some embodiments.
For example, waveform generator 110 may be configured to generate linear frequency modulated waveforms (sometimes termed “chirps” herein). In some embodiments, including the embodiments illustrated in FIGS. 8B, 8C, and 8D, waveform generator 100 may be configured to generate chirps using a closed-loop approach relying on a phase-locked loop (PLL) to generate chirps at a desired frequency.
