GB638911A - Improvements in or relating to privacy equipment for telephone and other communication systems - Google Patents
Improvements in or relating to privacy equipment for telephone and other communication systemsInfo
- Publication number
- GB638911A GB638911A GB629447A GB629447A GB638911A GB 638911 A GB638911 A GB 638911A GB 629447 A GB629447 A GB 629447A GB 629447 A GB629447 A GB 629447A GB 638911 A GB638911 A GB 638911A
- Authority
- GB
- United Kingdom
- Prior art keywords
- band
- bands
- class
- signal band
- width
- 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
- 230000005540 biological transmission Effects 0.000 abstract 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
- H04K1/00—Secret communication
- H04K1/04—Secret communication by frequency scrambling, i.e. by transposing or inverting parts of the frequency band or by inverting the whole band
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
638,911. Scrambling. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. March 5,1947, No. 6294. [Class 40 (iv)] In a secret transmission system in which parts of the signal band are scrambled and inverted, the whole of the signal band of frequency width x is fed in parallel to n paths comprising modulators AM1 ... CM1 each producing adjacent side-bands, the pairs of side-bands being displaced relatively to each other by x/n, band-pass filters AF1 ... CF1 having a common pass-band of width x/n, modulators AM2 ... CM2, supplied with one of a number of groups of predetermined carrier frequencies either directly from variable oscillators AO2 ... CO2 or indirectly by switching in various fixed frequency oscillators, and each producing two side-bands of width x/n, one only of which is within the original signal band, and band-pass filters AF2 ... CF2 arranged to pass the whole of the original signal band. Specifications 299,915, [Class 40 (iv)], and 309,063, [Class 40 (v)], are referred to.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR962063D FR962063A (en) | 1947-03-05 | ||
| GB629447A GB638911A (en) | 1947-03-05 | 1947-03-05 | Improvements in or relating to privacy equipment for telephone and other communication systems |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB629447A GB638911A (en) | 1947-03-05 | 1947-03-05 | Improvements in or relating to privacy equipment for telephone and other communication systems |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB638911A true GB638911A (en) | 1950-06-21 |
Family
ID=9811872
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB629447A Expired GB638911A (en) | 1947-03-05 | 1947-03-05 | Improvements in or relating to privacy equipment for telephone and other communication systems |
Country Status (2)
| Country | Link |
|---|---|
| FR (1) | FR962063A (en) |
| GB (1) | GB638911A (en) |
-
0
- FR FR962063D patent/FR962063A/fr not_active Expired
-
1947
- 1947-03-05 GB GB629447A patent/GB638911A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| FR962063A (en) | 1950-05-31 |
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