Pictures by Radio

Radio Record, Volume V, Issue 39, 8 April 1932, Unnumbered Page

Pictures by Radio

Apparatus for Christchurch

"THREE Fultograph due to arrive machines are shortly. in Christchurch They are primarily for the —

reception of pictures sent by wireless transmission. It is hoped to be able to adapt one machine for transmission purposes, and to use the others for reception. In appearance, each > machine is somewhat like an Edison gramophone, with a rotating cylinder, and a

threaded rod for carrying a stylus along the cylinder, which is covered with iodised. paper. The. incoming electrical impulses pass through the stylus and cause a brownish deposit, whose shade varies with the varying strength of the impulses. The impulses themselves owe their strength to the original black and white or

-, intermediate tones on the photograph being transmitted. The varying. currents at the transmitting end are amplified and made to modulate the carrier wave, an extra strong impulse being sent at each revolution as well. This trip signal operates the receiving end, which consists of a suitable receiver coupled to the Fultograph. A catch operates at each revolution of the Fultograph cylinder and holds it until the trip signal allows it to start each ‘revolution again. The clockwork which drives the cylinder is coupled through a magnetic clutch, a direct drive being out of the question. A delicate relay acts when the trip impulse arrives at each revolution and releases the catch on the Fultograph. It would be a difficult matter to synchronise each receiver with the transmitter cylinder, and so they are set to run just a shade faster than the transmitting one, giving time to be caught ready for the release impulse. A milliammeter is incorporated to sajast correct input, otherwise with too mu#h strength the relay would be functi ing with any strong impulse. A smudged picture would also result.