CA2171902A1 - Infra red communication systems - Google Patents
Infra red communication systemsInfo
- Publication number
- CA2171902A1 CA2171902A1 CA002171902A CA2171902A CA2171902A1 CA 2171902 A1 CA2171902 A1 CA 2171902A1 CA 002171902 A CA002171902 A CA 002171902A CA 2171902 A CA2171902 A CA 2171902A CA 2171902 A1 CA2171902 A1 CA 2171902A1
- Authority
- CA
- Canada
- Prior art keywords
- channel
- photodetector
- infra red
- receiving
- transmitter
- 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.)
- Abandoned
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M1/00—Substation equipment, e.g. for use by subscribers
- H04M1/02—Constructional features of telephone sets
- H04M1/04—Supports for telephone transmitters or receivers
- H04M1/05—Supports for telephone transmitters or receivers specially adapted for use on head, throat or breast
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R5/00—Stereophonic arrangements
- H04R5/033—Headphones for stereophonic communication
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2420/00—Details of connection covered by H04R, not provided for in its groups
- H04R2420/07—Applications of wireless loudspeakers or wireless microphones
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Health & Medical Sciences (AREA)
- Otolaryngology (AREA)
- Optical Communication System (AREA)
Abstract
A transmitter (10) and one or more receivers (12) are linked by infra red transmission via LED (14) and photodiode (16). In normal use, in-flight entertainment is modulated on left and right channels to give stereo sound on a user's earphones (28a, 28b). Transmitter public address signal on one channel and a code signal on the other channel. At the receiver (12), the code is detected (at 36) to operate receiver switching means (38) which disable the user's volume controls (30), thus ensuring that the public address message is heard at full volume. Also described are improved infrared signal receiving arrangements mitigating the effects of ambient light interference.
Claims (11)
1. A communication system comprising a master station including a transmitter, and a plurality of receiving stations, each receiving station having a respective individual volume control; and the master station includes means for overriding the volume controls of the receiving stations.
2. A system according to claim 1, which uses infra red transmission between the transmitter and the receiving stations.
3. A system according to claim 1 or claim 2, which is a stereo system having two channels and the overriding means comprises:
means in the master station for transmitting a code signal on one channel, and means in each receiving station responsive to said code signal to disable said one channel and to bypass the volume control of the other channel.
means in the master station for transmitting a code signal on one channel, and means in each receiving station responsive to said code signal to disable said one channel and to bypass the volume control of the other channel.
4. A system according to claim 3, in which the code signal is a continuous monotone.
5. A receiving apparatus for use in an infra red communication system, the apparatus being in the form of a head set having left and right earpieces joined by a head band, the apparatus including a plurality of photodetectors positioned on the head set and facing in different directions.
6. Apparatus according to claim 5, in which there are four photodetectors positioned one at the front and one at the rear of each earpiece.
7. Apparatus according to claim 5 or claim 6, including circuit means operating to reduce the signal from a given photodetector as the light incident thereon increases.
8. Apparatus according to claim 7, in which the circuit means comprises a feed-forward system.
9. Apparatus according to claim 8, in which the feed forward system, for each photodetector, includes a load element which provides a load resistance which varies inversely with the output current of the photodetector.
10. Apparatus according to claim 9, in which the load element is a bipolar transistor.
11. Apparatus according to claim 10, including a constant current source connected in parallel with the photodetector to the transistor emitter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002171902A CA2171902A1 (en) | 1996-03-15 | 1996-03-15 | Infra red communication systems |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002171902A CA2171902A1 (en) | 1996-03-15 | 1996-03-15 | Infra red communication systems |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2171902A1 true CA2171902A1 (en) | 1997-09-16 |
Family
ID=4157756
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002171902A Abandoned CA2171902A1 (en) | 1996-03-15 | 1996-03-15 | Infra red communication systems |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2171902A1 (en) |
-
1996
- 1996-03-15 CA CA002171902A patent/CA2171902A1/en not_active Abandoned
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |