An amplifier includes: a signal polarity inversion circuit; an amplifier circuit, connected with the signal polarity inversion circuit, generating a current based on a voltage, and outputting the current from output terminals; a signal polarity inversion circuit, having input terminals respectively connected with the output terminals, and outputting, in a non-inverted or inverted polarity, the current output from the amplifier circuit; a capacitor, obtaining a voltage based on the current output from the signal polarity inversion circuit; and a compensation circuit, wherein a node 12 and a node 10 are connected and a node 13 and a node 11 are connected, an input error component current comprising an input error component of the amplifier circuit is extracted from a voltage between terminals of the capacitor, and the input error component current that is extracted is supplied to the node 10 and the node 11.

The present invention discloses a transmission circuit having output power compensation mechanism. A base-band circuit receives and processes a digital input signal to perform conversion and amplification according to at least one gain parameter to generate an analog output signal. A frequency up-converting circuit performs frequency up-conversion on the analog output signal to generate an RF signal. A RF amplification circuit amplifies the RF signal to generate an output RF signal to an antenna. A temperature monitoring circuit monitors temperature of the RF amplification circuit to generate an instant temperature value thereof. A calibration circuit increases at least a part of the gain parameter when the instant temperature value makes a power of the RF amplification circuit decrease and decreases at least a part of the gain parameter when the instant temperature value makes the power increase.