Das Szenario
An embedded system designer needs to integrate a Quectel L76K GNSS module with an active patch antenna. The circuit requires stable 3.3V power, a bias-T to feed DC to the antenna LNA, and decoupling to ensure clean RF reception.
Was diese Zeichnung zeigt
Die dahinterstehenden Entscheidungen verstehen.
01
Use an inductor (L1) and capacitor (C2) to form a bias-T network, injecting DC onto the antenna line while blocking DC from the receiver input.
02
Add decoupling capacitors on both main VCC and VCC_RF pins for noise suppression.
03
Pull-up resistors on TXD/RXD lines ensure idle high levels when UART is unconnected.
Suitable for any project using active GNSS antennas with integrated LNA, where the receiver module provides a bias output (VCC_RF) or when an external bias supply is needed.