The utility model discloses a terrestrial
digital television system active receiving antenna with a
gain adjusting function, comprising an antenna circuit, the antenna circuit comprises a passive antenna, a
low noise amplifier, a
numerical control attenuator, an MCU
microprocessor and a power divider which are electrically connected in sequence and can receive UHF
frequency band signals, the passive antenna receives space
digital television signals, and the power divider receives the space
digital television signals. The
low noise amplifier is used for amplifying signals, a
processing program for changing the level of the
numerical control attenuator is arranged in the MCU
microprocessor, the
numerical control attenuator is used for controlling the attenuation amount of space digital television signals, and the MCU
microprocessor calls the corresponding
processing program to change the level of the numerical control attenuator so as to control the attenuation amount of the space digital television signals. According to the technical scheme of the utility model,
gain adjustment of the
active antenna of the digital television can be realized, power distribution or combination of digital television signals can be realized, a multi-stage
cascade combination function of the antenna can be realized, and the power divider can be flexibly used for circuit optimization.