According to a network
signal anti-interference transmission device, a
signal frequency modulation circuit receives a
signal source at the signal input end,
baseband frequency signals are generated through an oscillation circuit, and the
baseband frequency signals enter an impedance conversion circuit after being further subjected to
frequency modulation through an
automatic tuning circuit and enter a modulation circuit after being subjected to isolation, follow-up amplification and further isolation, so that the signal precision is improved; the frequency hopping
control circuit generates a
carrier signal by using an oscillation circuit; after frequency multiplication by the
frequency multiplier, signals are output to the modulation circuit. A linkage tuning loop follows the
automatic tuning loop to control the frequency of a
carrier signal to change frequency points.
Harmonic frequency interference with a
carrier signal after frequency multiplication of the interference signal is avoided. A
detector circuit feeds back a signal after frequency multiplication. On one hand, the effect of stabilizing the
oscillation amplitude is achieved, on the other hand, automatic frequency multiplication and
frequency modulation are achieved during amplitude attenuation, same-frequency interference in transmission is avoided, the modulation circuit modulates a high-frequency carrier signal and a
baseband frequency signal through a
triode Q5, and finally
frequency selection is conducted through an LC tuning loop, that is,
pilot-frequency interference is avoided, and then the signals are output toa
transmitter.