Patent ID: 11881880
Assignee: HUIZHOU TCL MOBILE COMMUNICATION CO., LTD.
Field: Telecommunications (Electrical engineering)
Classification: CPC H | IPC H

Claim 8:
9. A band14 signal suppression circuit comprising a duplexer, an active low-pass filter, and a resonant filter, an input of the duplexer is connected to a transmitter through a power amplifier, an output of the duplexer is connected to an input of the active low-pass filter, an output of the active low-pass filter is connected to a main antenna, the resonant filter is connected in parallel between the active low-pass filter and the main antenna;
wherein the power amplifier is configured to receive and power amplify the band 14 signal sent by the transmitter; and
the duplexer, active low-pass filter and resonant filter cooperatively filter and suppress second harmonic in the power amplified band14 signal to eliminate interference of the band14 signal with an assisted GPS signal wherein the resonant filter is an open line, the open line has a length of λ′, wherein λ′, λ′=¼λ, λ=c/f, c is a speed of light, and f is a frequency of the assisted GPS signal.