PURPOSE: To from an IC through mounting of the converter onto one chip to convert the video and aural signals of the base band into the VHF signal which can be received through the TV picture receiver, by forming the converter with the differential double balanced modulator, the carrier oscillating differential amplifier and FM differential oscillator.

CONSTITUTION: The converter to be formed into an IC consists of 2-input differential double balanced modulator circuit part A, differential amplifier circuit part B for carrier oscillation, FM differential oscillator circuit part C, and bias voltage generator circuit part D each. At part A the video signal is inserted to terminal 9 via capacitor C1 with application of DC bias VB3 via diode D1, and the aural FM signal is inserted to terminal 10 to carry out both the modulation of the video signal and the frequency conversion of the aural FM signal at one time. Part B uses the external coil and capacitor and decides the oscillation frequency via the parallel resonance. At part C the variable capacity is changed to vary the frequency and then obtain the FM signal. In such way, the IC formation is possible by adding a small number of parts to outside, thus realizing a low-cost converter featuring an easy control.