FR2769156A1 - Radio information dissemination system - Google Patents

Abstract

The coupling between transmitters on different sites allows information to be transmitted in different languages to all sites without interference.

Description

 The present invention relates to a new, individual and multilingual device allowing tourists to receive tourist messages by radio on an almost infinite number of sites in the same region and this without interference thanks to a particular type of radiation.

 On each site is placed a transmission bay of 3 to 6 transmitters connected to a specially studied antenna whose radiation lobe is folded over 30 "towards the ground.

 Each transmitter bay broadcasts from 3 to 6 messages in different languages evoking the history of the site, using miniMisc players connected to the corresponding transmitters.

Messages are recorded digitally.

 Each tourist has a receiver whose frequency corresponds to his language, and allows him to listen to a text lasting 15 to 20 minutes.

 All the sites are on the same frequency which allows tourists to move from site to site with the same receiver with an autonomy of 40 to 50 hours.

 Plate 1, figure 1, the sites are only spaced 2km apart in certain places, tourists have the freedom to choose the site of their choice, for example from 1 to 6.

 The highly selective receivers R1, R2, R3 (plate 3, FIG. 3) receive their respective frequencies and receive messages A, B, C from the transmitters.

 The particularity of the system (Figure 3) requires us to different spacing between channels due to the intermodulation products.

 FIG. 2 represents a radiation diagram at 26 MHz antenna (horizontal polarization).

 FIG. 4 represents a block diagram 3 to 6 channels with separation of the 25 kHz channels, loss of insertion 4.5 dB, isolation between channels at 50 from -47 dB and an admissible power of 4 W.

 FIG. 5 represents the curve of the transmitter, the sensitivity and the adaptation.

 Figure 6 shows three lines L1, L2, L3, these three lines are LC series.

 The resistors are arranged in the same way.

Value of the elements: ZC = Ro \ / ZL = Ro \ / Ce = 3C
Advantages at low frequencies, much less bulky than the L / d coaxial and especially less losses.

 Disadvantage at high frequencies, LC become too small to be reproducible.

 The three outputs are in overall phase at 1/4 wave in Teflon coaxial arranged in a particular way as close as possible to B N C plugs which makes it efficient isolation.

 The invention relates to new, individual and multi-lingual radio devices enabling tourists to pick up and listen with their receiver, within a radius of 500 meters around the sites, historical and informative messages on an almost infinite number of transmitters in a same region, without interference, thanks to a particular type of radiation from the antennas, while knowing that the frequencies used are the same.

 The tourists are then provided with receivers with a minimum autonomy of 40 hours, portable around the neck, and small footprint ensuring perfect mobility around the site.

 Transmitter devices (Plate 1, Figure 1, site from 1 to 6) allowing the dissemination of multilingual A, B, C messages on an almost infinite number of emitters thanks to horizontal radiation of strongly folded antennas Lobe of folded radiation from Plate 2, Figure 2.

 Tourists with receivers R1, R2, R3 (Plate 1, Figure 1) can listen to tourist and cultural messages.

 Figure 3 explains that the device is provided with an antenna (Y), a coupler (10), supplied with power (12) of + 35 dbm by the transmitters (A, B, C).

 The readers (M2, M2, M3) provide the modulation (9) recorded in digital and broadcast in analog at levels of + 6 dbm in voltage.

The peculiarity of the system (11) (plate 3, figure 3) obliges us to space between different channels due to the intermodulation products. The receptors R1, R2,
R3, have been studied for an average sensitivity of the order of 1.5 micro volts / 20 db, to avoid receiving certain beats between transmitters.

 The type of modulation on transmission is phase, it allows analog broadcasting of the different messages A, B, C, on the same antenna Y (Plate 3, Figure 3).

 The device has a coupling (10) (plate 3, FIG. 3) HF resistive of unconventional type whose isolation obtained between channels is only 48 dB with 25 kHz channel spacing (11). The insertion losses are 4.5 db which gives a transmission power (12) of + 30 dbm per channel.

 The receivers R1, R2 or R3 (13) (plate 3, figure 3) have a sensitivity or noise ratio / ratio of the order of 20 db to 1.5 micro volts, which also allows them to be insensitive to carrier of the neighboring site.

 As we say on page 1 of the description, the radiation lobe of each antenna is folded down sharply, a real example of the horizontal radiation lobe (Plate 2, Figure 2).

 Each transmitting bay is equipped with a 3-way coupler (board 4, figure 4) representing 3 resistive circulators (1, 2, 3) followed by a specific manufacturing (4), it is based on a global phasing at the output regardless of the length of the input quarter wave. (plate 6, figure 6) we describe the theoretical principle of the coupler.

 On board 5, figure 5, (Ul) we describe the isolation between channels, (D2) the insertion loss, (D3) the impedance matching of the coupler

Claims (6)

 1) Radio devices with transmitters and with receivers, individual and multilingual allowing tourists to pick up and listen with their receiver, in a ravon of 500 meters around the sites, historical and informative messages on an almost infinite number of transmitters in a same region, without interference, thanks to a particular type of radiation from the antennas, while knowing that the frequencies used are the same.  2) Device according to claim 1 characterized in that the receivers have an autonomy of 40 hours minimum, are portable around the neck, and small in space ensuring perfect mobility around the site.  3) Device according to claims 1 or 2 characterized in that the transmitting devices (plate 1, Figure 1, site 1 to 6) allow the dissemination of messages A, B, C multilingual on an almost infinite number of transmitters thanks to horizontal radiation from the strongly folded antennas (Plate 2, Figure 2).  4) Device according to any one of the preceding claims, characterized in that each transmission bay is provided with an antenna (Y), with a coupler (10), supplied with power (12) of + 35 dbm by the transmitters (A, B, C).  5) Device according to claim 4 characterized in that compared to the transmitters (A, B, C), the readers (M2, M2, M3) provide the modulation (9) recorded in digital and broadcast in analog at levels of + 6 dbm in tension.  6) Device according to claims 4 or 5 characterized in that between each transmitters (A, B, C) there are spacings between different channels due to the intermodulation products, the receivers R1, R2, R3, being studied for an average sensitivity of the order of 1.5 micro volts / 20 db, to avoid receiving certain beats between transmitters.