US2208916A - Wired radio transmitting system - Google Patents

Wired radio transmitting system Download PDF

Info

Publication number
US2208916A
US2208916A US174379A US17437937A US2208916A US 2208916 A US2208916 A US 2208916A US 174379 A US174379 A US 174379A US 17437937 A US17437937 A US 17437937A US 2208916 A US2208916 A US 2208916A
Authority
US
United States
Prior art keywords
lines
group
attenuation
groups
transformer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US174379A
Other languages
English (en)
Inventor
Wiessner Alfred
Spang Wolfgang
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Alcatel Lucent Deutschland AG
C Lorenz AG
Original Assignee
Standard Elektrik Lorenz AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Standard Elektrik Lorenz AG filed Critical Standard Elektrik Lorenz AG
Application granted granted Critical
Publication of US2208916A publication Critical patent/US2208916A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
    • H04H20/65—Arrangements characterised by transmission systems for broadcast
    • H04H20/76—Wired systems
    • H04H20/77—Wired systems using carrier waves
    • H04H20/81—Wired systems using carrier waves combined with telephone network over which the broadcast is continuously available

Definitions

  • broadcast performances, alarm signals and the like may be transmitted over wire lines, such as telephone networks, by means of high frequency carrier currents.
  • wire lines such as telephone networks
  • a transmitter has to be matched to a plurality of subscribers lines, e. g., 1,000 lines, each of which has an electric separating filter that serves to convey the high connection.
  • the attenuation of the lines may,
  • the lines are arranged in groups in accordance with their attenuation, for instance in groups of 16 units each, and to each of these groups is added the resistance of one unit of the next group of greater line attenuation.
  • a resistance adaptation must be effected in accordance with the square root of the number of connected members. In the example here assumed a resistance adaptation according to ⁇ /16 will thus be necessary.
  • the decrease in the voltage in direction away from the transmitter is inversely proportional to the resistance transformation, that is to say, is pro- ,2 portional to Since the number of the lines comprised in a group determines the voltage transformation, a further feature of the invention provides that the grouping, effected in accordance with thev attenuation of the lines, should be such that the voltage at the line ends be the same in the various groups.
  • the attenuation difference between the groups must be proportional to the natural logarithm of the voltage transformation ratio, that is, proportional'to the natural logarithm of the square root of the number which indicates how many lines are comprised in a group. In the present example this attenuation difference must be proportional to log. nat. ⁇ /16.
  • I denotes a transmitter which is arranged, for instance, as a wide-band amplifier for a plurality of high frequency waves, or which consists of a group of cooperating transmitters which are 45 all of symmetrical construction.
  • groups 3, 5. l of electric separating filters A are connected by high frequency transformers 2, 4, 6.
  • the filters A of group 3 are connected in parallel to transformer 2, and those of groups 5 are connected in parallel to transformer 4, while the filters A of group I are similarly connected to transformer 6.
  • To each filter A a two-wire line L is joined that belongsto one or several subscribers stations R, such as broadcast rer DCvers or the like. For simplicity only a few of the stations R are shown.
  • Transformer t takes the place of a filter A of group 3, while transformer 6 replaces a filter A of the group 5.
  • 16 units are connected to each transformer, the filters A of group 3 together with transformer 4 being connected to transformer 2, and the filters A of group 5 and transformer 6 being connected to transformer 4 while to transformer 6 the filters A of group 'i are joined.
  • the lines L of group I have a smaller attenuation resistance than those of group 5, while the lines L of group 5 have a smallerattenuatio-n resistance than those of group 3.
  • transmitter l to be matched to a load resistance of 150 ohms.
  • the resistance of each filter A is likewise 150' ohms.
  • the transformer 2 In order to match the IB members of the group 3' to the transmitter I the transformer 2 must have a transformation ratio of V16, that is, a transformation ratio of 4:1.
  • the filters A of group 5 being connected in parallel are effective only as the sixteenth part of the resistance of 150 ohms.
  • transformer 4 In order to give them the resistance of each filter A of the group 3, transformer 4 must effect a voltage transformation that according to the said number 16 is likewise defined by the ratio 4:1. Since such resistance-transfer causes the voltage to be decreased by the same value the filters.
  • a of group 5 will receive only the fourth part of the voltage applied to the filters A of the group 3.
  • the construction of transformer 6 and the requisite adaptation of voltage and resistances are accomplished in the same manner.
  • the groups 3, 5, I thus are alike inasmuch as all the filters A have the same input resistance, and they are different from each other inasmuch as in group 3 the attenuation of the lines L is greater than in group 5 while in this group the line attenuation is greater than in group i which thus has the least line attenuation.
  • To group 7 a voltage equal to the fourth part of the voltage of group 5 is applied while the voltage applied to group 5 is equal to the fourth part of the voltageprevailing in group 3.
  • the attenuation resistances between the groups are so' chosen that the voltage applied to each group will be one-fourth of the voltage applied to the preceding group, i. e., sufficient to ensure that approximately the same tension shall be available at all the subscribers stationsv R.
  • a group of filters which is associated with lines of correspondingly less attenuation may be arranged.
  • a filter A of group 5 may be replaced by an additional transformer associated with groups of lines, thus being replaced by an arrangement of the kindshown at 6, l. The manner of accomplishing this depends upon economical and technical considerations which are different depending upon the nature of the networks to be fed.
  • the output lines are fed perfectly symmetrically, means being provided to prevent the output lines from receiving any energy whatsoever over any leakage capacities or constructional asymmetries. It is known per se to provide for a symmetrical construction of the circuit arrangements of carrier. systems. In prior devices, however, the object ofsuch symmetrical construction was not to feed the lines symmetrically but to suppress in these modulated lines the carrier. No attention has been paid to feeding the lines symmetrically because there is no relation between feeding and modulation. However, experiments have shown that it is just the mode of feeding the output lines which requires consideration especially in the case of cables employed for transmitting communications at high frequency.
  • the described arrangement has the special advantage that by commingling lines of different attenuation the whole of the network can be advantageously matched to a communication trans: mitter.
  • An advantage feature of the described arrangement is that all the lines are fed perfectly symmetrically.
  • these lines are telephone cables over which also low frequency communications may be transmitted. Feeding the lines symmetrically insures that there shall be no influence upon lines not fed with high frequency energy and that therefore high frequency energy can merely be taken from the lines fed therewith.
  • the novel arrangement of the high frequency transformers enables arrangement of the high frequency transformers enables a network to be fed from transmitters or amplifiers without additional high frequency ampli- Y bombs having to be provided even in the case of line groups of very different attenuation.
  • the low frequency portion of the system is shown, the low frequency portion being omitted for clearness.
  • the arrangement of the low frequency portion is such that the low frequency energy is conveyed to the subscribers lines directly and at a point in advance of the filters A, and that means for separating low frequency from high frequency energy is provided in the subscribers stations too.
  • a wired-radio transmitting arrangement comprising a high frequency transmitter, a plurality of successive stages each comprising a group of wire lines associated with the transmitter in successive stages, each stage having greater attenuation than the succeeding stage, and means for matching the resistance of each stage to the succeeding stage, whereby the input amplitude of each stage will be in proportion with its attenuation.
  • the impedance matching means comprises a high frequency transformer for each group.
  • the impedance matching means comprises a high frequency transformer for each group symmetrically connected with respect to the units thereof.
  • An arrangement according to claim 1 having a plurality of lines connected in parallel in each group, each preceded by an electric separating filter so as to offer the same input impedance, a transformer interconnecting said transmitter and one of said groups, and transformers and transmission lines interconnecting said other groups comprising said successive stages.
  • each of said stages includes a plurality of transformers, and additional transmission lines for interconnecting said successive stages.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
US174379A 1936-11-27 1937-11-13 Wired radio transmitting system Expired - Lifetime US2208916A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE498627X 1936-11-27

Publications (1)

Publication Number Publication Date
US2208916A true US2208916A (en) 1940-07-23

Family

ID=20310732

Family Applications (1)

Application Number Title Priority Date Filing Date
US174379A Expired - Lifetime US2208916A (en) 1936-11-27 1937-11-13 Wired radio transmitting system

Country Status (5)

Country Link
US (1) US2208916A (en(2012))
BE (1) BE424554A (en(2012))
FR (1) FR828734A (en(2012))
GB (1) GB498627A (en(2012))
NL (1) NL50604C (en(2012))

Also Published As

Publication number Publication date
GB498627A (en) 1939-01-11
FR828734A (fr) 1938-05-27
NL50604C (en(2012))
BE424554A (en(2012))

Similar Documents

Publication Publication Date Title
US3530260A (en) Transistor hybrid circuit
US2229078A (en) Radio relaying system
GB405026A (en) Carrier current transmission system
US2208916A (en) Wired radio transmitting system
US3535640A (en) Reduction of distortion and losses in cable television distribution systems
US1900045A (en) Two-way negative resistance repeater
US2352254A (en) Frequency modulated wave transmission
US2000190A (en) Radio receiving system
US1812624A (en) Telephone and telegraph signaling system
US1658337A (en) Carrier-wave signaling system
US1570770A (en) Means for and method of reducing interference
US1952411A (en) Transmission network
US1448408A (en) Duplex carrier wave system
US2140915A (en) Distortion correction in wave transmission
US1594454A (en) Transmission circuits
US2630493A (en) Carrier telegraph system
US1601074A (en) Multifrequency-current transmission
US1698777A (en) Radiorepeater
US1836114A (en) System of carrier current signaling on power lines
US1858307A (en) Means for compensating for nonlinear distortion in transmission circuits
US2370853A (en) Electrical carrier wave signaling system
US1675893A (en) Carrier-wave transmission
US2272389A (en) Unattended mechanical repeater
US1529801A (en) Multiplex submarine cable
US1548062A (en) Coupling arrangement for multiplex transmission