GB330642A - Improvements in or relating to electrical signalling systems - Google Patents
Improvements in or relating to electrical signalling systemsInfo
- Publication number
- GB330642A GB330642A GB858229A GB858229A GB330642A GB 330642 A GB330642 A GB 330642A GB 858229 A GB858229 A GB 858229A GB 858229 A GB858229 A GB 858229A GB 330642 A GB330642 A GB 330642A
- Authority
- GB
- United Kingdom
- Prior art keywords
- curve
- frequencies
- gives
- noise
- cable
- 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
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
- H04B3/02—Details
- H04B3/04—Control of transmission; Equalising
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
Abstract
330,642. Western Electric Co., Ltd., (Bell Telephone Laboratories, Inc.). March 16,1929. Amplifying systems; simultaneous telegraphy and telephony.-In a signalling system, particularly for telephony over a submarine cable, the signals are pre-distorted in such a manner that the amplitudes of the several components are rendered more nearly equal, at a point in the transmission channel e.g. at the receiving end, and at least equal to the amplitude of corresponding interfering or noise frequencies, the original relationship between the amplitudes of the signal components being restored at the receiving end. Fig. 1 shows a two-way terminal arrangement associating a land line 11 u'ith a submarine cable 18, and Figs. 2 and 3- show amplitude-frequency curves for various stages at the transmitting and receiving ends, respectively. Curve a represents the amplitude distribution in the air before exciting microphone 9 and curve b the distribution after passing through the line 11. A filter 13 suppresses all frequencies below 400 and above 2500 (curve b<1>), thus permitting more energy to be put into the remaining frequencies. Two attenuation equalizing amplifiers 14, Hi give respectively the curves c, c', the latter introducing the required distortion, and a uniform amplifier 16 then gives the curve d which represents the currents actually put into the cable. The unequal attenuation produced by the cable gives a reception curve e, Fig. 3, which owing to the pre-distortion is more nearly uniform and is at all points above the noise-distribution curve f by a minimum found necessary for intelligible reception. A uniform amplifier 19 and a distorting amplifier 21 produce too curves g, h, and i, k, the latter representing the currents actually put into the receiving telephone which gives acoustic waves represented by m, n. A filter 20 suppresses frequencies below 400 and <Lbove 2500 in the noise currents. The frequencyband below 400 may be used for simultaneous telegraphy. Specifications 151,140 and 202,284 are referred to.
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB858229A GB330642A (en) | 1929-03-16 | 1929-03-16 | Improvements in or relating to electrical signalling systems |
DEE39066D DE608530C (en) | 1929-03-16 | 1929-04-06 | Method for the transmission of signals over long, busy telephone lines |
FR673993D FR673993A (en) | 1929-03-16 | 1929-04-25 | Telephone transmission |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB858229A GB330642A (en) | 1929-03-16 | 1929-03-16 | Improvements in or relating to electrical signalling systems |
Publications (1)
Publication Number | Publication Date |
---|---|
GB330642A true GB330642A (en) | 1930-06-16 |
Family
ID=9855230
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB858229A Expired GB330642A (en) | 1929-03-16 | 1929-03-16 | Improvements in or relating to electrical signalling systems |
Country Status (3)
Country | Link |
---|---|
DE (1) | DE608530C (en) |
FR (1) | FR673993A (en) |
GB (1) | GB330642A (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE749876C (en) * | 1940-11-27 | 1944-12-07 | Carrier frequency system for the simultaneous transmission of frequency bands with high frequency-dependent and frequency-independent average energy distribution | |
DE3226279A1 (en) * | 1982-07-14 | 1984-01-19 | Neumann Elektronik GmbH, 4330 Mülheim | ARRANGEMENT FOR COMPENSATING DIFFERENT DAMPING BEHAVIOR OF TELECOMMUNICATION LINES |
-
1929
- 1929-03-16 GB GB858229A patent/GB330642A/en not_active Expired
- 1929-04-06 DE DEE39066D patent/DE608530C/en not_active Expired
- 1929-04-25 FR FR673993D patent/FR673993A/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
DE608530C (en) | 1935-01-25 |
FR673993A (en) | 1930-01-22 |
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