GB253152A - Improvements in or relating to wireless telegraphy and telephony - Google Patents
Improvements in or relating to wireless telegraphy and telephonyInfo
- Publication number
- GB253152A GB253152A GB14359/26A GB1435926A GB253152A GB 253152 A GB253152 A GB 253152A GB 14359/26 A GB14359/26 A GB 14359/26A GB 1435926 A GB1435926 A GB 1435926A GB 253152 A GB253152 A GB 253152A
- Authority
- GB
- United Kingdom
- Prior art keywords
- wave
- frequency
- aerial
- valve
- short
- 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
- H04B7/00—Radio transmission systems, i.e. using radiation field
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
Abstract
253,152. Marconi's Wireless Telegraph Co., Ltd., (Assignees of Peterson, H. O.). June 8, 1925, [Convention date]. Transmitting systems; heterodyne receiving systems.-In order to overcome the effects of fading, static, and other disturbances, the short carrier wave on which the signal is imposed is periodically varied in frequency, and at the receiver is heterodyned with a locally-produced wave having the same periodic frequency variations. The variation in frequency may be of the order of 1 in 3000, and these variations may occur 100 times per second. As shown in Fig. 2, a long-wave oscillator 57 at the transmitter station B has its frequency periodically varied by the rotation of the movable plates, of a small condenser 59 connected in parallel with the main condenser 58. The long wave is amplified and radiated bv the aerial 68 and is also combined with a short wave from the oscillator 44 in the grid circuit of a modulator 48. From the resultant frequencies in the output circuit 51, the sum frequency is selected and radiated by the aerial 52. The shorter radiated wave is broken up by a signal key 45 or modulated by a microphone in any usual way. At the receiving station C the shorter wave with its periodic frequency variations is picked up by the tuned aerial 20, and transferred to the detector valve 23. The longer wave with its periodic frequency variations is picked up by a second tuned aerial 27 and is combined in the modulator 36 with a local short wave of a steady frequency differing from that of the source 44. The resulting sum frequency is selected at 37 and passed into the grid circuit of the valve 23. The two inputs to this valve thus bear synchronous frequency variations,. and their difference is a steady frequency to which the output circuit 25 is tuned. This steady frequency is interrupted or modulated according to the signals imposed by the key 45 or equivalent microphone. In a modification shown in Fig. 1, the long wave with its periodic frequency variations is generated at a separate station A and is radiated to the transmitter station D where it is picked up by the aerial 11. From this long wave a short wave is generated by an harmonic-producer or frequency-multiplier 14 and is radiated from the aerial 18. At the. receiving station C, one aerial 27 picks up the long wave, and a second aerial 20 the short wave. The long wave is multiplied in frequency by an apparatus 31 similar to that at the station D and is then combined in the valve 36 with a steady frequency from a local source 35. The output of the valve 36 is combined in the valve 23 with the short wave received on the aerial 20, and from the output a wave of the steady difference frequency is selected by the tuned circuit 71, and passed to the detector 40. For multiple working, a single long-wave source may be used for imposing its frequency variations on a number of short-wave channels.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US35528A US1708518A (en) | 1925-06-08 | 1925-06-08 | Communication system |
Publications (1)
Publication Number | Publication Date |
---|---|
GB253152A true GB253152A (en) | 1926-10-14 |
Family
ID=21883260
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB14359/26A Expired GB253152A (en) | 1925-06-08 | 1926-06-07 | Improvements in or relating to wireless telegraphy and telephony |
Country Status (2)
Country | Link |
---|---|
US (1) | US1708518A (en) |
GB (1) | GB253152A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1022648B (en) * | 1955-11-26 | 1958-01-16 | Nordwestdeutscher Rundfunk Ans | Method for wireless transmission of messages with suppression of selective fading |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2416336A (en) * | 1942-05-21 | 1947-02-25 | Standard Telephones Cables Ltd | Radio receiver |
US2422664A (en) * | 1944-07-12 | 1947-06-24 | Bell Telephone Labor Inc | Wobbled radio carrier communication system |
US2530140A (en) * | 1944-08-11 | 1950-11-14 | Tung Sol Lamp Works Inc | Secret signaling system |
US2784311A (en) * | 1952-03-21 | 1957-03-05 | Crosby Lab Inc | Suppressed-carrier reception |
-
1925
- 1925-06-08 US US35528A patent/US1708518A/en not_active Expired - Lifetime
-
1926
- 1926-06-07 GB GB14359/26A patent/GB253152A/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1022648B (en) * | 1955-11-26 | 1958-01-16 | Nordwestdeutscher Rundfunk Ans | Method for wireless transmission of messages with suppression of selective fading |
Also Published As
Publication number | Publication date |
---|---|
US1708518A (en) | 1929-04-09 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
GB704221A (en) | Improvements in or relating to radio transmission systems for stereophonic signals and transmitters and receivers for use therein | |
GB551472A (en) | Improvements in modulated high frequency carrier wave signalling systems | |
US1744036A (en) | Process for radiotelegraphic or radiotelephonic communication | |
US2400133A (en) | Double modulation radio receiver | |
GB253152A (en) | Improvements in or relating to wireless telegraphy and telephony | |
GB548599A (en) | Improvements in frequency modulation systems for radio communication | |
GB454257A (en) | Improvements in or relating to modulated carrier wave receivers | |
US2687476A (en) | Means for and method of frequency conversion | |
US3370235A (en) | Dual pilot frequency-correcting terminal stations for satellite repeater system | |
GB242653A (en) | Improvements in radio signalling systems | |
GB320024A (en) | Improvements in or relating to multiplex communication systems | |
GB161580A (en) | Improvements relating to the reception of radio signals | |
US1797284A (en) | High-frequency signaling | |
US1771700A (en) | Method of and apparatus for multiplex signaling | |
GB448448A (en) | Improvements in or relating to modulated carrier wave receivers | |
US1748277A (en) | Radiant signaling system | |
US1954185A (en) | Method of transmitting signals on short radiowaves | |
US1674696A (en) | Radio receiving system | |
US1911091A (en) | Signaling | |
US2428010A (en) | Single carrier telephone and telegraph pulse multiplex system | |
US1478047A (en) | Radio receiving system | |
GB257294A (en) | Improvements in or relating to radio receivers | |
US1660072A (en) | Duplex transmission system | |
GB571580A (en) | Frequency modulation detector | |
US2712598A (en) | Wireless broadcasting systems |