BE388125A

BE388125A -

Info

Publication number: BE388125A
Authority: BE

Description

       

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  Perfectionnements aux montages de   T.S.F.   



   La présente invention concerne les montages employas en T.S.F. et dénommés d'une façon générale .superhétérodynes' 
Ainsi que celà est bien connu, dans les montages de ce genre, on se heurte à l'inconvénient que les stations locales produisent des sifflements qui gênent la réception d'autres stations. Cet inconvénient peut être considéra- blement atténué en augmentant la fréquence de battement entre l'hétérodyne et la station reçue. 



   Conformément à l'invention, cette condition est satisfaite enmunissant l'appareil de plusieurs fréquences de battement appropriées chacune à la gamme de fréquences à recevoir. 



   A titre   d'exemple ,   s'il   s'agit   d'un appareil éta- bli de façon' à recevoir deux gammes de longueurs d'ondes, chaque étage de moyenne fréquence sera muni soit de deux cir- cuits, transformateurs, autotransformateurs ou filtres à 

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 bande différents accordés chacun sur la fréquence appropriée et commutés en même temps que les circuits oscillants de réception, soit d'un seul circuit, transformateur, auto- transformateur ou filtre à bande dans lequel des changements de connexion permettront d'obtenir les deux fréquences en même temps que la commutation des circuits oscillants le réception. 



   Semblables montages et modes de commutation étant de pratique courante, il est superflu d'en donner de plus amples détails.



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  Improvements to T.S.F.



   The present invention relates to assemblies employed in T.S.F. and generally referred to as superheterodynes'
As is well known, in arrangements of this kind, one comes up against the drawback that local stations produce whistles which interfere with the reception of other stations. This drawback can be considerably alleviated by increasing the beat frequency between the heterodyne and the received station.



   According to the invention, this condition is satisfied by providing the apparatus with several beat frequencies each appropriate to the frequency range to be received.



   By way of example, if it is a question of an apparatus established so as to receive two ranges of wavelengths, each medium frequency stage will be provided either with two circuits, transformers, autotransformers or filters

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 different band, each tuned to the appropriate frequency and switched at the same time as the receiving oscillating circuits, either of a single circuit, transformer, autotransformer or band filter in which connection changes will obtain the two frequencies in the same time as the switching of the oscillating circuits the reception.



   As such assemblies and switching modes are common practice, it is unnecessary to give further details.

Claims

ABSTRACT. EMI2.1

= 4. = + = - t <= -) <=. Tes4 <! ' The subject of the invention is: 1) An assembly method for reducing whistling in so-called devices. superheterodynes., characterized by the application of several beat frequencies each appropriate to the range of frequencies to be received.

2) Embodiment of the assembly method mentioned under 1, characterized in that each mid-frequency stage comprises two circuits, transformers, autotransformers or different band filters, each tuned to the frequency appropriate to the receiving frequency range .

3) Embodiment of the assembly method mentioned under 1, characterized in that each medium frequency stage comprises a single circuit, transformer, autotransformer or band filter provided with connections making it possible to obtain two different frequencies appropriate to the frequencies. - reception frequencies.

4) Embodiment of the devices mentioned under 1 to 3, characterized in that the switching of the oscillating receiving circuits is carried out simultaneously with the switching of the circuits, transformers, autotransformers or band filters of each medium frequency stage.