V-F conversion-based 2FSK modulation circuit

The invention discloses a V-F conversion-based 2FSK modulation circuit. The V-F conversion-based 2FSK modulation circuit at least comprises an integrating circuit, a hysteresis comparator, a discharge switch circuit and a sine wave shaping circuit, wherein the integrating circuit is used for generating a triangular wave output which is in proportion to a first input control voltage; the hysteresis comparator is used for converting the triangular wave output by the integrating circuit into a square wave to control the discharge switch circuit; the discharge switch circuit is used for discharging to an integrating capacitor of the integrating circuit regularly under the control of the hysteresis comparator; the sine wave shaping circuit is used for converting the triangular wave into a continuous-phase sine wave. According to the V-F conversion-based 2FSK modulation circuit, continuous-phase 2FSK is realized without an additional frequency source by utilizing the characteristic that the oscillation frequency of an output rectangular wave is in direct proportion to the control voltage by V-F conversion, improving the circuit, adding series of waveform conversion circuits, and then outputting the sine wave which changes between two different frequencies according to the change of two levels of the control voltage.