GB1537267A - Carrier-frequency communications transmission systems - Google Patents
Carrier-frequency communications transmission systemsInfo
- Publication number
- GB1537267A GB1537267A GB48160/75A GB4816075A GB1537267A GB 1537267 A GB1537267 A GB 1537267A GB 48160/75 A GB48160/75 A GB 48160/75A GB 4816075 A GB4816075 A GB 4816075A GB 1537267 A GB1537267 A GB 1537267A
- Authority
- GB
- United Kingdom
- Prior art keywords
- band
- khz
- transposition
- super
- modulation
- 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
- H04J—MULTIPLEX COMMUNICATION
- H04J1/00—Frequency-division multiplex systems
- H04J1/02—Details
- H04J1/04—Frequency-transposition arrangements
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Transmitters (AREA)
Abstract
1537267 FDM transposition arrangements SIEMENS AG 25 Nov 1975 [15 Jan 1975] 48160/75 Heading H4M In a carrier frequency communications system in which a first super-group of FDM channels in the frequency band 312-552 kHz is transmitted without transposition while at least one further super-group in the same band is transposed to an adjacent band, either 60-300 kHz or 564 to 804 kHz, the transposition is effected in two stages of modulation, firstly to an intermediate highfrequency band and from there to the required band, so that filter design problems are simplified. Following the first modulation stage 1, the transposed super-group is passed through a band pass filter 2, which has a blocking attenuation for the 312-552 kHz band which is less than the necessary 54 db. (because there will be attenuation in the second modulation stage) and an upper band limit above the lower of the two side bands resulting from the first modulation step (in fact for easy filter design, this limit is above both side bands but is such as to block higher harmonic bands). The second modulation stage 3 is followed by a low pass filter 4 which blocks the frequency band resulting from the second transposition of the higher (and unwanted) of the two sidebands. Design of such a filter is straightforward due to the improved percentage separation of the two sidebands. The procedure is used in a CCITT 4 MHz system in which 16 super-groups are established and the carrier used (2968 kHz and 2356 kHz) may be developed from any of those available in the system.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2501421A DE2501421C2 (en) | 1975-01-15 | 1975-01-15 | CARRIER FREQUENCY MESSAGE TRANSMISSION SYSTEM |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1537267A true GB1537267A (en) | 1978-12-29 |
Family
ID=5936503
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB48160/75A Expired GB1537267A (en) | 1975-01-15 | 1975-11-24 | Carrier-frequency communications transmission systems |
Country Status (16)
| Country | Link |
|---|---|
| JP (1) | JPS5196207A (en) |
| AT (1) | AT351078B (en) |
| AU (1) | AU501143B2 (en) |
| BE (1) | BE837591A (en) |
| BR (1) | BR7600190A (en) |
| CH (1) | CH607504A5 (en) |
| DE (1) | DE2501421C2 (en) |
| DK (1) | DK13776A (en) |
| FR (1) | FR2298238A1 (en) |
| GB (1) | GB1537267A (en) |
| IE (1) | IE41957B1 (en) |
| IL (1) | IL48594A (en) |
| IT (1) | IT1059566B (en) |
| LU (1) | LU73763A1 (en) |
| NL (1) | NL7600407A (en) |
| SE (1) | SE7600164L (en) |
-
1975
- 1975-01-15 DE DE2501421A patent/DE2501421C2/en not_active Expired
- 1975-11-07 LU LU73763A patent/LU73763A1/xx unknown
- 1975-11-24 GB GB48160/75A patent/GB1537267A/en not_active Expired
- 1975-11-25 AT AT894275A patent/AT351078B/en not_active IP Right Cessation
- 1975-12-01 IE IE2611/75A patent/IE41957B1/en unknown
- 1975-12-02 IL IL48594A patent/IL48594A/en unknown
- 1975-12-04 AU AU87263/75A patent/AU501143B2/en not_active Expired
- 1975-12-05 CH CH1582575A patent/CH607504A5/xx not_active IP Right Cessation
-
1976
- 1976-01-09 SE SE7600164A patent/SE7600164L/en unknown
- 1976-01-09 FR FR7600480A patent/FR2298238A1/en not_active Withdrawn
- 1976-01-13 JP JP51003137A patent/JPS5196207A/ja active Pending
- 1976-01-14 BR BR7600190A patent/BR7600190A/en unknown
- 1976-01-14 DK DK13776*#A patent/DK13776A/en unknown
- 1976-01-14 IT IT19237/76A patent/IT1059566B/en active
- 1976-01-15 BE BE163533A patent/BE837591A/en unknown
- 1976-01-15 NL NL7600407A patent/NL7600407A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| SE7600164L (en) | 1976-07-16 |
| LU73763A1 (en) | 1976-06-11 |
| AU501143B2 (en) | 1979-06-14 |
| IT1059566B (en) | 1982-06-21 |
| BE837591A (en) | 1976-05-03 |
| AT351078B (en) | 1979-07-10 |
| JPS5196207A (en) | 1976-08-24 |
| NL7600407A (en) | 1976-07-19 |
| BR7600190A (en) | 1976-08-31 |
| IL48594A (en) | 1977-12-30 |
| CH607504A5 (en) | 1978-12-29 |
| AU8726375A (en) | 1977-06-09 |
| IE41957L (en) | 1976-07-15 |
| DE2501421B1 (en) | 1976-05-06 |
| FR2298238A1 (en) | 1976-08-13 |
| ATA894275A (en) | 1978-12-15 |
| DK13776A (en) | 1976-07-16 |
| DE2501421C2 (en) | 1979-11-22 |
| IL48594A0 (en) | 1976-02-29 |
| IE41957B1 (en) | 1980-05-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PCNP | Patent ceased through non-payment of renewal fee |