GB1498672A - Monitoring device for a signal transmission system - Google Patents
Monitoring device for a signal transmission systemInfo
- Publication number
- GB1498672A GB1498672A GB1421475A GB1421475A GB1498672A GB 1498672 A GB1498672 A GB 1498672A GB 1421475 A GB1421475 A GB 1421475A GB 1421475 A GB1421475 A GB 1421475A GB 1498672 A GB1498672 A GB 1498672A
- Authority
- GB
- United Kingdom
- Prior art keywords
- fault
- gates
- channel
- gate
- faulty
- 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
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/74—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for increasing reliability, e.g. using redundant or spare channels or apparatus
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Safety Devices In Control Systems (AREA)
- Electronic Switches (AREA)
Abstract
1498672 Measuring voltage VEREINIGTE FLUGTECHNISCHE WERKE-FOKKER GmbH 7 April 1975 [5 April 1974] 14214/75 Heading G1U A monitoring device for a transmission system having a plurality of channels nominally carrying the same information comprises a number of comparators connected to every possible combination of pairs of channels and providing outputs whenever the difference therebetween exceeds a specified level to operate devices to block the faulty channel, wherein the comparators re-connect any blocked channel if the fault lasts for less than a predetermined time. Comparator circuit, Fig. 2 The input circuit 56 connects the input signals U E1 , U E2 to two operational amplifiers 50, 51 such that any difference between them greater than a level determined by the voltage at the tapping point of the voltage divider 53 connected to the inverting inputs causes a positive voltage to immediately turn on transistor 63 via either diode 62, 69. This causes a low input to NAND gate 60, providing a high level 'fault' output, if the excessive difference disappears after a short time, the output reverts to a low level. However if the amplifier output lasts long enough to charge one of capacitors 64, 70 to a high enough level, thyristor 66 is fired providing a low signal to the other NAND gate input. Even if the difference now returns to zero, the thyristor continues to conduct, storing the 'fault' signal until a voltage is applied to the clear input. This turns on transistor 68, shorting the thyristor current, reducing it below its holding value and the thyristor becomes blocked. Monitor system, Fig. 1 Each information channel E 1 -E 4 in e.g. a flight control system is passed via summing amplifiers V 1 -V 4 and gates S 11 -S 43 to a combining network R 1 -R 16 which produces four signals A 1 -A 4 representing the arithmetic mean of the input signals E 1 -E 4 . Each amplifier V 1 -V 4 output is compared with each other output in six comparators M 1 -M 6 of the type shown in Fig. 1. Groups of AND gates e.g. G 11 -G 13 or G 21 -G 23 determine from the comparator outputs which channel is faulty and operate respective switches e.g. S 11 -S 13 to disconnect that channel, ensuring that the mean signals A 1 -A 4 are formed only from valid information. Associated with each de-coding group e.g. G 11 -G 13 is an OR gate e.g. G 14 which passes any single fault signal to a further OR gate G 38 (also receiving signals from all the other de-coding groups) to turn off a transistor, releasing a relay RL 1 and completing a circuit to a fault indicator L 1 . If all three de-coding gates indicate a fault i.e. the fault is in the information channel rather than a failure in one part of the monitor system, an AND gate e.g. G 15 provides a high signal to a group of NAND gates G 16 -G 37 . Since only one fault is so far detected the outputs of these gates are still high. If a second channel fails, the relevant de-coding group will block that channel, a further signal will be sent to gate G 38 as well as gates G 39 and G48, G 46 and G 47 which release two further relays RL 21 , RL22 completing circuits to two indicator lights L 2 . At the occurrence of the second fault, one gate in each of the remaining two de-coder groups will also indicate a fault and the associated switches in the non- faulty channels will begin to respond. However, a further signal is sent via e.g. AND gate G 25 to the gates G 1 6 -G 37 which determine which two channels are faulty and block the incorrectly indicating gates e.g. G 31 , G 41 . Since the gates respond more quickly than the switches, the non-faulty channels are not blocked. Facilities are provided for inserting test signals via the summing amplifiers V 1 -V 4 and monitoring the de-coder group responses as well as the relay contact changes.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19742416602 DE2416602C3 (en) | 1974-04-05 | 1974-04-05 | Redundant signal transmission system |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1498672A true GB1498672A (en) | 1978-01-25 |
Family
ID=5912228
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1421475A Expired GB1498672A (en) | 1974-04-05 | 1975-04-07 | Monitoring device for a signal transmission system |
Country Status (3)
Country | Link |
---|---|
DE (1) | DE2416602C3 (en) |
FR (1) | FR2266924B3 (en) |
GB (1) | GB1498672A (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4370745A (en) * | 1980-11-14 | 1983-01-25 | Bell Telephone Laboratories, Incorporated | Fail-safe transmission system |
JPS59215884A (en) * | 1983-05-24 | 1984-12-05 | Canon Inc | Printer |
DE3420365A1 (en) * | 1984-06-01 | 1985-12-05 | Brown, Boveri & Cie Ag, 6800 Mannheim | METHOD FOR SWITCHING BETWEEN REDUNDANT TRANSMISSION PATHS |
-
1974
- 1974-04-05 DE DE19742416602 patent/DE2416602C3/en not_active Expired
-
1975
- 1975-04-07 FR FR7510798A patent/FR2266924B3/fr not_active Expired
- 1975-04-07 GB GB1421475A patent/GB1498672A/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
DE2416602B2 (en) | 1979-03-15 |
DE2416602C3 (en) | 1979-10-31 |
DE2416602A1 (en) | 1975-10-09 |
FR2266924A1 (en) | 1975-10-31 |
FR2266924B3 (en) | 1977-12-16 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PCNP | Patent ceased through non-payment of renewal fee |