Novel frequency modulation circuit

Abstract

The invention discloses a novel frequency modulation circuit. The novel frequency modulation circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor, a first inductor, a second inductor, a diode, a first triode and a second triode, wherein the first end of the first capacitor is a signal input end, the second end of the first capacitor is respectively connected with the first end of the second capacitor and the first end of the first resistor, and the second end of the second capacitor is grounded. The novel frequency modulation circuit has the advantages that modulation signals are used to change the base bias of an oscillator to change inter-electrode capacitance so as to change frequency, the capacity of the fourth capacitor and the fifth capacitor is quite small and output through the second triode, influence of impedance change on an oscillating circuit is reduced, the interference resistance of the circuit can be enhanced effectively, and frequency modulation of ultrahigh frequency signals can be achieved.

Description

technical field [0001] The invention relates to a frequency modulation circuit, in particular to a novel frequency modulation circuit. Background technique [0002] Frequency modulation means that the frequency of the high-frequency carrier is not a constant, it is a modulation method that changes within a certain range with the modulation signal, and its amplitude is a constant. Correspondingly, amplitude modulation means that the frequency of the carrier frequency is constant, and its amplitude The value changes with the modulating signal, and the general interference signal is always superimposed on the signal, changing its amplitude. Therefore, although the amplitude of the FM wave will change after being interfered, the amplitude limiter can be used at the receiving end to cut off the change in the signal amplitude. The traditional FM circuit has a low ability to modulate the frequency of the UHF carrier signal, and the frequency is too high. After that, it will reduce...

AI Technical Summary

Problems solved by technology

Therefore, although the amplitude of the FM wave will change after being interfered, the amplitude limiter can be used at the receiving end to cut off the change in the signal amplitude. The traditional FM circuit has a low ability to modulate the frequency of the UHF carrier signal, and the frequency is too high. After that, it will reduce its anti-interference ability

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