Abstract: This invention relates to a modulator circuit (2) for a video system such as a VCR. The modulator circuit (2) is selectably operable in any one of a plurality of modes of operation in order to comply with the operating standard of the video system. The modulator circuit comprises oscillator circuit (4, 10) for generating a carrier signal having a selectably variable frequency, and a modulating circuit (3) coupled to receive the carrier signal and having an audio input (24) for receiving an audio signal and a video input (26) for receiving a video signal, the modulating circuit using the video and audio signals to generate a modulated output signal on the carrier signal, the generation of the modulated output signal depending on selectably variable operating parameters of the modulating circuit.