Issue link: https://resources.mouser.com/i/1484091
18 The Future of Automotive system calculator (Figure 6). Figure 7 illustrates that there will be up to 18dB desense in the V2X receiver if the notch filter is not used on the 5GHz Wi-Fi path vs. almost zero desense with a well-designed notch filter leveraging the benefits of BAW technology. Another critical challenge that needs careful attention is that V2X needs to coexist with electronic toll collection (ETC). The problem here is that the ETC spectrum (for Europe it is 5795-5815MHz, for China it is 5790-5800MHz UL, 5830- 5840MHz DL) is too close to the V2X spectrum (for North America and Europe 5855-5925MHz, for China 5905- 5925MHz), as shown in Figure 8. One way to address this issue is by notching out the ETC spectrum with a properly designed filter on the V2X path. Let's look at Europe. Figure 9 illustrates a comparison of spectrum emissions mask with and without the notch filter at the input of V2X FEM. The plot to the left shows that the spectrum emissions from the output of the PA cannot pass the ETC spec of -65dBm/MHz, and hence V2X cannot coexist with ETC unless it is addressed in the ETC radio or through some software mitigation methods. The plot to the right shows that V2X can coexist with ETC if a well designed notch filter is inserted in the V2X radio. Now, let's look at the state of the spectrum for China (Figure 10). Again, as can be seen from the plot to the left, ETC cannot coexist with V2X unless it is addressed in the ETC radio. The plot to the right shows spec compliance with margin to ETC spec of -65dBm/MHz, if a well-designed filter is used in the V2X radio. Figure 7: Rx band noise and desense with and without QPQ2230Q notch filter. (Source: Qorvo) Figure 6: Wi-Fi front-end with a V2X notch (QPQ2230Q) on the 5GHz path. Yet even BAW band pass filters are not a complete solution to coexistence issues in the V2X environment. We must also consider the essential role played by notch filters. While the band pass filter discussed above provides adequate out-of-band rejection, Qorvo's QPQ2230Q notch filter "notches out" Rx band noise in the V2X band on the 5GHz Wi-Fi path, thus preventing Rx band noise from coupling back into the V2X system and causing desense issues, as illustrated in the