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

Claim 0:
1. A band14 signal suppression circuit comprising:
a duplexer;
an active low-pass filter; and
a resonant filter, wherein 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, and the resonant filter is connected in parallel between the active low-pass filter and the main antenna;
the power amplifier receives a band 14 signal sent by the transmitter for power amplification;
the duplexer, the active low-pass filter and the resonant filter cooperatively filter and suppress second harmonic in the band14 signal after power amplification to eliminate interference of the band14 signal to an assisted GPS signal;
the resonant filter is an open line, the open line has a length of λ′, wherein λ′, λ′¼λ, λ=c/f, is a speed of light, and f is a frequency of the assisted GPS signal; and
the suppression circuit further comprises an inductor with one end being grounded and the other end being connected to a common end of the resonant filter and the main antenna.