Apparatus for electrical signal transmission; Apparatus for electronic image transmission; Apparatus for information transmission; Apparatus for sound transmission; Apparatus for television transmission; Apparatus for the transmission of data; Apparatus for the transmission of electrical signals; Apparatus for the transmission of images; Apparatus for the transmission of sound; Apparatus for the transmission of sound or images; Apparatus for use in digital communication transmission; Apparatus for use in high-frequency transmission; Electric apparatus for the transmission of analogue signals; Electric apparatus for the transmission of digital signals; Electrical apparatus for the transmission of audio signals; Image transmission apparatus; Pulse code modulation apparatus for transmission via cable; Pulse code modulation apparatus for transmission via microwave; Pulse code modulation apparatus for transmission via optical fibres; Pulse code modulation apparatus for transmission via radio; Pulse code modulation apparatus for transmission via satellite; Pulse code modulation instruments for transmission via cable; Pulse code modulation instruments for transmission via microwave; Pulse code modulation instruments for transmission via radio; Pulse code modulation instruments for transmission via satellite; Secure transmission apparatus; Secure transmission instruments; Television signal transmission apparatus; Transmitters for use in the transmission of television programmes; Video cameras for use in television transmission suites