GB218282A - Improvements in secret signalling systems - Google Patents
Improvements in secret signalling systemsInfo
- Publication number
- GB218282A GB218282A GB1495124A GB1495124A GB218282A GB 218282 A GB218282 A GB 218282A GB 1495124 A GB1495124 A GB 1495124A GB 1495124 A GB1495124 A GB 1495124A GB 218282 A GB218282 A GB 218282A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sub
- band
- frequencies
- bands
- inverted
- 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
- 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)
- Transceivers (AREA)
Abstract
218,282. Western Electric Co., Ltd., (Assignees of Mathes, R. C.). June 30, 1923, [Convention date]. Secret signalling systems; thermionic modulation systems.-Speech or other band frequencies are divided into a plurality of sub-bands, some or all of which, are inverted and are simultaneously impressed on the carrier wave. The Figure shows filters F<1> - - F<3> separating speech frequencies from the microphone circuit 11 into three sub-bands, which are inverted by modulators M<1>, M<3> by impressing on them frequencies from sources 15, 20, 22 equal in each case to the sum of the edge frequencies of the sub-band, and passing only the lower side band of the resultant by filters F<1> - - F3 to the balanced transmitting modulator TM. The antenna TA is preferably sharply tuned to discriminate in favour of one side band, but if a very high frequency carrier is employed other means of securing single side-band transmission may be employed. At the receiver, the carrier frequency is re-inserted, and the sub-bands are again separated and inverted as at the transmitting station and the combined resultant is applied to the receiver.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US648647A US1542565A (en) | 1923-06-30 | 1923-06-30 | Secret signaling |
| US654803A US1573924A (en) | 1923-07-31 | 1923-07-31 | Secret signaling |
| US681346A US1533311A (en) | 1923-12-18 | 1923-12-18 | Secret signaling |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB218282A true GB218282A (en) | 1925-03-05 |
Family
ID=27417815
Family Applications (3)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1495124A Expired GB218282A (en) | 1923-06-30 | 1924-06-20 | Improvements in secret signalling systems |
| GB1761324A Expired GB226488A (en) | 1923-06-30 | 1924-07-23 | Improvements in secret signalling systems |
| GB1821624A Expired GB219987A (en) | 1923-06-30 | 1924-07-30 | Improvements in secret signalling systems |
Family Applications After (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1761324A Expired GB226488A (en) | 1923-06-30 | 1924-07-23 | Improvements in secret signalling systems |
| GB1821624A Expired GB219987A (en) | 1923-06-30 | 1924-07-30 | Improvements in secret signalling systems |
Country Status (4)
| Country | Link |
|---|---|
| DE (1) | DE466687C (en) |
| FR (1) | FR585788A (en) |
| GB (3) | GB218282A (en) |
| NL (1) | NL16701C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2132205A (en) * | 1937-06-23 | 1938-10-04 | Bell Telephone Labor Inc | Secret transmission |
| DE1196713B (en) * | 1962-08-30 | 1965-07-15 | Deutsche Bundespost | Procedure for voice encryption |
-
0
- NL NL16701D patent/NL16701C/xx active
-
1924
- 1924-06-20 GB GB1495124A patent/GB218282A/en not_active Expired
- 1924-06-27 FR FR585788D patent/FR585788A/en not_active Expired
- 1924-06-29 DE DEI24920D patent/DE466687C/en not_active Expired
- 1924-07-23 GB GB1761324A patent/GB226488A/en not_active Expired
- 1924-07-30 GB GB1821624A patent/GB219987A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| NL16701C (en) | |
| GB219987A (en) | 1925-10-30 |
| GB226488A (en) | 1925-06-25 |
| DE466687C (en) | 1928-10-13 |
| FR585788A (en) | 1925-03-06 |
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