A Low Power Interference Robust IR-UWB Transceiver SoC for WBAN Applications - Ultra-Wideband and 60 GHz Communications for Biomedical Applications - page 35

Fig. 12 Ultra-wideband (UWB) pulse searching algorithm timing diagram

Fig. 12 , incoming UWB pulses occur at duration window corresponding to NR 3 and
PR 3 , which have the highest number of count. During detection, noise and glitches
could randomly increase the register counts, such as NR 2 /PR 2 and NR 9 /PR 9 .By
setting proper threshold in decision FSM (NR i or PR i > 12), we should be able to
mask these detection errors and find the correct timing location for incoming UWB
pulses.
The flowchart for pulse detect algorithm is illustrated in Fig. 13 a. Most of the time,
positive and negative edge-triggered registers will record same number of UWB pulse
detection. Therefore, either one can be chosen for subsequent UWB pulse detection.
In the proposed algorithm, we choose the duration window corresponding to NR i ,
if NR i = PR i . However, if the incoming pulse is occurring right at the transition

edge, the corresponding edge-triggered registers might fail to detect pulses due to
metastability issue. Therefore, both positive and negative edge triggered flip-flop and
registers are included to overcome the problem. If positive (negative) edge-triggered
flip-flop encounters meta-stability issue and fails to detect incoming signal, negative
(positive) edge-triggered flip-flop should still be able to detect incoming pulse and
result in NR i > PR i (or PR i > NR i ).
Once UWB pulse searching algorithm completes, the exact duration window
where UWB pulses occur will be known. UWB pulse tracking algorithm as shown
in Fig. 13 b will begin. Pulse detection will span three consecutive duration windows.
The center duration window is determined from pulse searching algorithm. A tracking