Rx signal goes through a device consisting of 2 back-to-back diodes providing protection for the receiver's front end.
2.
In semiconductor devices, a "'backward diode "'( also called "'back diode "') is a variation on a Zener diode or tunnel diode having a better conduction for small reverse biases ( for example 0.1 to 0.6 V ) than for forward bias voltages.
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