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Millimeter wave (mmWave) radios offer attractive high bandwidths and small antenna sizes to help enabled modern miniaturized wireless systems. However, generation and distribution of a local oscillator (LO) at 10s of GHz consumes significant amounts of power. This problem is compounded when utilizing high-order QAM modulation schemes which demand very low jitter: for example, 256-QAM requires <350fs, which is very difficult and demands a high-power LO (e.g., 36mW in [1], which is even higher power than the LNA). On the other hand, a similar jitter spec can be achieved at low frequencies with much lower power consumption (e.g., 1mW [2]). This trade-off is illustrated in Fig. 1 (left). One approach to reduce the frequency and power requirements of LO generation is to perform sub-sampling (SS): as illustrated in Fig. 1 (right), down conversion in a SS receiver occurs by directly sampling the mmWave …