DE2813973A1 - SYSTEM FOR TRANSMISSION OF TELEVISION IMAGES WITH SLOW SCANNING - Google Patents

Description

The invention relates to a system for the transmission of Slow scan television images using a unit for recording or storing Images and / or the generation of image signals with a first coupling device, a communication channel, a second coupling device and with a playback r or storage unit for reproducing or storing the image signals. Such a system is for punk amateur traffic has been developed.

In the Punkamateur Techniques (SSTV) described above, a system for recording and reproducing television images used in both the number of images per unit of time and the resolution, that is, the number of Image lines, to limit the bandwidth required for transmission, are greatly reduced, to one Value that is compatible with the language, for example 3 kHz. The following numerical values can be given as examples be: During the presentation with such an SSTV procedure the number of frames can be, for example, one per six or seven seconds, with the resolution being 120 lines per frame is limited.

These slow scan television pictures can, for example by light point scanners or flying spot scanners or Vidicon tubes are recorded while the video information then on a separate auxiliary or auxiliary or Sub-carrier of, for example, 2 kHz is modulated. Both amplitude and frequency modulation are possible, with the modulated signal thus obtained having a bandwidth that is less than 3 kHz.

The image information obtained by slow scanning can also be transferred to a conventional cassette or tape recorder

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recorded and used by this tape or cassette in the usual way, i.e. played back. This image information can be transmitted by licensed radio amateur devices on the assigned amateur frequency bands. After reception, the slowly scanned television signals can be converted in a picture display unit in order to generate an image ; as an alternative to this, these signals can also be stored in a normal sound recording device for later display. The image signals can be used, for example, to generate an image by means of a cathode ray tube with extended afterglow or extended afterglow duration; As an alternative to this, the image signals can also be used for an image storage tube or a conventional television set (monitor) which has been equipped with an image and memory scanning converter.

It is an object of the present invention to improve the system described above in such a way that it can be used for can be used in many, essential areas of application in industry or in society in general.

This is done in the above-described system according to the present invention Invention achieved in that an existing audio channel is used as the communication channel, such as a telephone, radio or voice radio channel.

Due to the reduced bandwidth of the slowly scanned television channel, normal telephone lines can be used for transmission or radio channels are used, so that many applications are possible, in particular for the Control and transmission of information.

According to a further, expedient embodiment of the system, the first coupling device consists of an electroacoustic one Converter, such as a loudspeaker,

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and the electro-acoustic converter that is relevant for the Audio communication channel, such as a microphone. The second coupling device consists of the electroacoustic one Transducer relevant to the audio communication channel, such as a Telion receiver, as well as a acoustoelectric transducer, such as a microphone.

As an alternative to this, according to a second, expedient embodiment, the first and second coupling devices in the system each consist of an electrical connection, whereby the video signal is sent directly to the telephone line or coupled to the input of the transmitter of the radio channel or from the telephone line or the receiver output of the radio-r channel is removed.

The invention is illustrated below with the aid of exemplary embodiments for. some application models explained in more detail with reference to the accompanying schematic drawings. Show it

1 shows a conventional recording device with a flying spot scanner or a video tube,

2 shows a conventional display unit with a cathode ray tube or a storage tube,

Fig. 3 shows the system according to the present invention, in which the slowly sampled television signals through a normal telephone line can be transmitted, and

Fig. 4 shows a system according to the present invention at which transmitted the slowly sampled television signals through a normal radio communication channel will.

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FIG. 1 shows a conventional circuit arrangement for the recording of slowly scanned images; here are a luminous point scanner or flying spot scanner or a vidicon tube 1, a sawtooth or tilt generator 2, a synchronization circuit 3, an amplifier 4, a 2 kHz oscillator 5 and a modulator 6 are provided. The output signal the circuit arrangement is indicated at 7a, where the video information is in the form of a slowly scanned Television signal is supplied.

FIG. 2 shows a conventional circuit arrangement for the reproduction of slowly sampled television signals 7b an amplifier 8, a filter circuit 9, a synchronization circuit 10, a sawtooth or Tilt generator. 11 and a cathode ray tube with extended afterglow time or a storage tube 12 is provided. In order to increase the afterglow time, phosphors or phosphors of the P7 type can be used, for example.

Figure 3 shows the system according to the present invention. From a camera 1 or a cassette or tape recorder 13 becomes the slowly sampled signal of a unit 14, which can form part of the circuit arrangement according to FIG. The output signal 7a of the unit

14 is placed on a first coupling device 15, which consists of a loudspeaker 16 and a microphone 17, which is part of a common telephone line 18. At the end of the telephone line 18 the signal goes to the second coupling device 19 passed through the listener 20 to the microphone input 21 of the playback or recording part of the system. The signal 7b is sent to the reproduction unit 12 or a recording device 13 via an amplifier 22. As an alternative to this, the first coupling device

15 and / or the second coupling device 19 from a

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direct electrical connection 24, 25 exist, which is connected directly to the telephone line.

Figure 4 shows a further embodiment of the invention, in which the slowly sampled signals do not pass a telephone line, but instead through a radiotelephone or walky-talky unit 26. Even here can again the first coupling device 15 from a Loudspeaker 16 and a microphone 17 or a direct one There are electrical connection 24 to the signal 7a the input of the transmitter 27 of the radio telephone or the radiotelephone or the device for wireless telephony. The second coupling device can then off the speaker output 20 of the receiver 28 and the microphone input 21 of the rest: part of the circuit arrangement or from a direct connection 25 between the receiver output and the input of the remaining part of the circuit arrangement. Especially with high signal / noise ratios A direct connection in the image information can be useful.

It is also possible, for example by means of a luminous point scanner or a flying spot scanner, by using three color filters (red-green-blue) on both the Transmitter and receive color information to be transmitted, creating three consecutive individual images can be transmitted with different color filters.

The system described above can work for many different Applications in the field of control and / or monitoring as well as the transmission of information. For example, all types of drawings, Photographs, "life" pictures of damage, security monitoring, industrial processes, etc. through normal telephone lines or voice radio connections are transmitted. For the purposes of seafaring, pictures of storm damage can be used

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of technical defects or destruction as well as the effects of illness can be transmitted to patients on board a ship for diagnosis on land using the marine radiotelephone. Use cases for aviation include hijacking attempts, security on board aircraft, test flights, technical defects or malfunctions, etc., which can be transmitted to the ground using the usual radio communication channels, and conversely, documents can be transmitted from the ground to the aircraft.

Many applications are also possible in the field of improving the technical equipment of the police. Patrol cars or separate crime prevention units can use slow-scanned television images exchange through existing telephone or radio communication channels.

And finally, such a system can also be used for private purposes can be used, whereby instead of the more expensive broadband lines for the exchange of images already Existing telephone lines are used.

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Claims (3)

Claims \\ J System for the transmission of television images with slow scanning by means of a recording or storage unit for recording and / or generating the image signals with a first coupling device, with a communication channel, with a second coupling device and with a playback or storage unit for playback or
Storage of the bi] & 5 signals, characterized in that the communication channel is an existing audio channel, such as a conventional telephone or radio connection. 809840 / 1O90 ORIGINAL INSPECTED 2. System according to claim 1, characterized in that the first coupling device from an electroacoustic transducer, in particular a loudspeaker, and one for the existing sound channel relevant acoustoelectric transducer, in particular a microphone, and that the second coupling device from the electroacoustic transducer relevant for the existing sound channel, in particular a telephone receiver and an acousto-electric transducer, in particular a microphone. 3. System according to claim 1, characterized in that the first and / or second coupling device consists of a direct There is an electrical connection through which the television signal is sent directly to the telephone connection or the transmitter input of the Radio connection created or removed from the telephone connection or the receiver output of the radio connection will. 809840/1090