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Sending pictures by radio .. Electronics

Sending pictures by radio

Images can be sent all over the world using radio signals. This is done by placing the image on a rotating cylinder and scanning it electronically and sending it in the form of adjacent lines (244). Then the radio signals corresponding to the light and dark areas are sent to a receiver that includes another cylinder that rotates at the same speed as the first cylinder, and on the recording head a writer moves along the cylinder drawing marks and lines whose degree of darkness and lightness is proportional to the transmitted lines. Thus, after several cycles, an image identical to the transmitted image is formed on the cylinder. It is possible to record the signals related to the image on a magnetic tape to save it or to resend it when the conditions for sending short waves over long distances become suitable. To ensure this synchronization process, the tape contains two tracks, one for the information related to the image and the other for a crystal oscillator. Then this signal is amplified and passes through an audio engine whose speed depends on the frequency of the signal itself (245). Another motor receives the amplified crystal oscillator signals and operates an intermediate gear in its cycles that indicates the difference between the speeds of the two motors and is connected to a circuit whose task is to correct the speed of the tape on which the image was recorded, which ensures the synchronization process between transmission and reception. Remote measurement is the transfer of information from some devices to other recording devices far away from them, such as transferring information from satellites to the ground. This is done by converting the "information" into an audio signal that in turn is converted into transmitted data. An example of this is the dual-channel diode that produces a voltage proportional to the temperature and then takes it to an oscillator whose frequency changes with this voltage. The audio signal is also sent and a ground station picks it up and decodes it (246).

243 - Determining the distance of the target and navigation by sounding.

244 - Sending images by radio.

245 - The process of synchronizing the image tape sent by radio.

246 - Measuring temperatures from a distance by radio.