US2190436A - Receiver arrangement - Google Patents

Description

. Feb. 13, 1940.

HANS-WERNER STEINHAUSEN 2,190,436

RECEIVER ARRANGEMENT Filed June 8, 1938 Egi INVENTOR HAA/S-A ERIVIE'IQ y/mmusz-w ATTORNEYS Patented Feb. 1940 um n stares Hans-Werner Steinhausen, BerIimGermany, as-

signor to Tclefunken Gesellschaft fiir Drahtlose Telegraphic m. b. H., Berlin, Germany,

'"j I a corporation of Germany ,Application June 8, 1938, Serial No. 212,423 i I In Germany June 9, 1937 signedtothe same assignee as the present application, his proposed in connection with a receiving arrangement to'terminate the double wire line connected to the antenna with a resistor having the-value" of the wave resistance, ifel,

surge impedance and across a "filter .pervious only to' 'high frequencies,- whereby said resistor'is chosen for the high frequencies for which the capacitive resistance of the double" wire lineis lower than-its wave resistance. Furthermore, in this case the antenna is matched with a resistance that is higher thanthe wave resistance,

case of broadcast waves and long waves since the matching i. e.'the proportion between the re- 5 sistance of the cable or double wire line and the antenna resistance is a poorone. The an tenna resistance being primarily a capacitive resistance, will then be higher than in the case of short" waves so that it is 'high' ascompared with the wave resistance whereby only a small part of the total antenna voltage appears there.- at. For this reason according to the patent the terminal resistor is rendered ineffective in the case of broadcast waves and long waves and 'for these wave ranges the antenna is accurately or approximately matched with the capacitive resistance of the cable. .Sincein this case both the antenna resistance and the cable resistance are capacitive. the proportion between both and hence the matching has always the mostfavorable value throughout the broadcast wave range and long wave range.

With the present invention the short wave reception in such a receiving "arrangement is improved. in a simple manner. Herein lies an advantage in view of the fact that in the receiver as well as in an antenna amplifier eventually present the short waves are detrimentally resistor is efiective and whose secondary winding then differ appreciably from the ratio 1:1.

4 Claims. (01. 178-44) According -to U. 's; Patent No. 2.112320, as-" 'terminal resistor and the filter are joined, while has one end connected to the point at which the with the double wire line Lacross a transformer more especially withthe capacitive resistance of the double wire line. The terminal resistance whose value is that of the wave resistance of the line is designatedby W. This terminal resistor is connected in series with a condenser C which in this caseassumes the task of the filter-since K. 'On the other wave ranges the main voltage is developed across the condenserC so that the series connection'of the primary and secondary.

winding of the transformer K solelyhas' the 7 effect of a lead-in. In fact the" short wave transformer has buta few windings The output is connected either to one or several receivers,

or to an antenna amplifier from which the energy is passed to the receivers across a second double wire line.

In the example of construction according to Figure 2 no transformer is provided between the antenna and the double Wireline. This condition exists when using the principle of the above patent in the casein which the capacity of the cable is of the order of the antenna capacity because in this case a transformer is no longer required since its transformation ratio does not This condition exists if for instance a rod antenna has a capacity of mi. while a rather short cable need simply be used for instance of a length of 7 m. and having a capacity of 200 mi.

when figuring with a capacity of 30 mi. per

meter. Since such a cable still has a length requiring termination of the cable onthe short wave range 0/; of a wave of 28 m. being equal to the length of the cable), it would be necessary to provide an antenna transformer for the broadcast waves and long waves unless the idea of the above patent is used. In fact, if at a wavelength of 60 m. the capacitive resistance of thiscable is ohms so that as regards value it does not differ from the usual value of the wave resistance of ohms, the capacitive resistance of this cable is already 50 ohms at a wavelength of 200 m., and 5000 ohms at a Wavelength of 2000 m. Therefore, in case of a fixedly connected. terminal resistor and without the use of an antenna transformer, i. e., without utilizing the idea of'the above patent there would be obtained in the range between 200 m. and 2000m. a voltage division and hence a loss of 1:3 up" to 1:30.

In the case of the short cable length assumed and in the circuit according to Figure 2 considered more especially for arrangements. with antenna amplifiers, there is obtained a more uni;

form efficiency than without short wave transformer, since the difference is. then especially large' between the capacitive resistance of the cable on the broadcast wave rangeand long. Wave range and the Wave resistance or match ing with the input of the amplifier in casewof In fact, an additional voltagein-' so thatan additional transformer betweencable and antenna amplifier would for these wave ranges not bring about'a particular advantage. Nevertheless itwould be possible'inFigure 2 and especially in Figure. Iito place in parallel to the output terminals one or several parallel transformers: for the broadcast waves and long waves eventually by connecting chokes aheadthereto.

1. In a receiving system for receiving waves over longandshort wave ranges, an'energy collector; a: two. conductor transmission lineconnected-at one end tothe: collector, said transmission line having. a: length which is at leastcomparable-to awavelength at a short wave range,- awtransformer having a primary winding and-asecondary. winding, a condenser and an impecb ance meansconnected in series across'the other endoi the. line, said impedance 1 means including; said primary winding and having substantially the same value as. the surge; impedance of the line, a pair of terminals for connecting the 'line to a utilization device, and means including the secondary of said transformer and said con-' denser in series for connecting said two. termi-' nals together. 2. A receiving'system for receiving waves over awid'erange of frequencies;comprisjing ian energy j collector, a two-conductor transmission line coupled at one end to the collector, said transmis- I sion line having av length comparable to a wave length having the range but small in length compared to a wave length corresponding to the lowest frequency of said range, a terminating resistance and a con- I I,

denser connected in series across the line, said terminating resistance having substantially the highest frequency of said same-svalue as'th'e surge impedanceof the line,.

a short wave transformer having a primary windinganda secondary winding, a pair of termi-,

nals adapted to be connected to a utilization de vice, meansjfor connecting thepri-maryawinding' of said transformer across I saidterminatingrre 'sistor, and: a connection between said two terminals, said connection including the secondary. of said. transformer andgsaid condenser m series..

. 3. Anqinput'circui-t for a shortwave'andglong wave receiver-comprisingi,an: antenna; a: trans-v ission line having one .end coupled. to the antenna; the other 1 end of the transmissionvline having a-- filter: constituted by a resistance and a capacity connected across the lineandi awhigh frequency transformer, the primary of which is connected across the filterresistance andthe secondary of which togetherwi-ththe filter conev adapted to be ceiver 4; A circuit for-coupling ashort wave'and long Wave receiver to anantenna, comprising a trans-. mission. linehaving one end coupled to the- -an.- tenna, a filter constituted by a. series resistance andacapacity connected across the transmission line at thaother end, a high'frequencytranse former ha ing its primary connectedacross. the filter resistance, a pair. of output terminals adapt ed. to be connected; to. the inputfof the receiver; said output terminals having connectedbetween them the secondary ,otjthe highfrequentyiransformerand the capacity ofthe'terminating filter.

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