GB535927A - Improvements in telegraphones - Google Patents
Improvements in telegraphonesInfo
- Publication number
- GB535927A GB535927A GB9003/40A GB900340A GB535927A GB 535927 A GB535927 A GB 535927A GB 9003/40 A GB9003/40 A GB 9003/40A GB 900340 A GB900340 A GB 900340A GB 535927 A GB535927 A GB 535927A
- Authority
- GB
- United Kingdom
- Prior art keywords
- coil
- condenser
- oscillator
- pole pieces
- frequency
- 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
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/02—Recording, reproducing, or erasing methods; Read, write or erase circuits therefor
- G11B5/027—Analogue recording
- G11B5/03—Biasing
Landscapes
- Recording Or Reproducing By Magnetic Means (AREA)
Abstract
535,927. Telegraphones. ELECTRICAL RESEARCH PRODUCTS, Inc. May 21, 1940, No. 9003. Convention date, July 29, 1939. [Class 40 (ii)] In making a telegraphone record, the record strip 1 is first subjected by pole pieces 2 to an erasing alternating magnetic flux of frequency higher than any to be recorded and then by other pole pieces 3, to the recording magnetic flux accompanied by an alternating magnetic flux of higher frequency than the erasing flux but of lower intensity. As shown, the. alternating fluxes are produced by alternating currents derived from a single thermionic oscillator 7 rich in harmonics. The fundamental frequency of this oscillator is fed through a condenser 10 to the coil 9 of the pole pieces 2, the condenser and the coil being tuned to accept this frequency. The third harmonic is supplied to the coil 15 of the pole pieces 3 through a condenser 17, an,adjustable resistance 16, the coil and the condenser being tuned to accept this harmonic, and a coil 22 and condenser 23 tuned to the fundamental being interposed between the oscillator and the condenser 17 to choke off the fundamental. These devices can be connected for recording or reproducing by means of a switch 4. In the recording position, power from source 5 is fed through choke 24 to oscillator 7, and microphone 11 is connected through amplifier 12 to coil 15. In the reproducing position of the switch 4, the microphone and the oscillator 7 are cut off, and the coil 15 is connected through equalizing circuit 18 to amplifier 12, the output of which is then connected to a loudspeaker 19.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US535927XA | 1939-07-29 | 1939-07-29 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB535927A true GB535927A (en) | 1941-04-25 |
Family
ID=21985309
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9003/40A Expired GB535927A (en) | 1939-07-29 | 1940-05-21 | Improvements in telegraphones |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB535927A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS52109917A (en) * | 1976-03-11 | 1977-09-14 | Victor Co Of Japan Ltd | Magnetic erasing and recording system |
-
1940
- 1940-05-21 GB GB9003/40A patent/GB535927A/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS52109917A (en) * | 1976-03-11 | 1977-09-14 | Victor Co Of Japan Ltd | Magnetic erasing and recording system |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US2119584A (en) | Pick-up device for electrical musical instruments | |
GB1334179A (en) | Apparatus for producing a low distortion pulse width modulated inverter output | |
GB535927A (en) | Improvements in telegraphones | |
GB684626A (en) | Improvements in or relating to electric amplifier arrangements of the kind which includes a magnetic amplifier | |
GB429987A (en) | Improvements in or relating to sound recording and reproduction devices | |
US2697756A (en) | Magnetic recording apparatus | |
GB800392A (en) | Improvements in or relating to logic "not" circuits | |
US2258990A (en) | Electric piano | |
US1532513A (en) | Telephone circuit | |
GB782572A (en) | Improvements in and relating to reproduction from magnetic records | |
US2189161A (en) | Sound reproducing apparatus and a wiring circuit therefor | |
GB306044A (en) | Improvements in and relating to sound reproducing apparatus | |
GB498986A (en) | Improvements in or relating to electric current converters | |
GB487488A (en) | Improvements in signal receiving apparatus for telephone systems | |
GB195879A (en) | Improvements in electro-magnetic sound-boxes for phonographs and the like | |
GB473512A (en) | Improvements relating to electric amplifiers | |
JPS5217011A (en) | Magnetic circuit of the speaker | |
GB474898A (en) | Improvements relating to apparatus for use in the recording and reproduction of sound | |
GB538058A (en) | Improvements in or relating to moving coil pickups | |
FR2446043A1 (en) | Electric string instrument pick=up - uses current induced in strings by vibration in transversal magnetic field and supplied to amplifier | |
GB490225A (en) | Improvements in and relating to electrical pick-ups | |
GB594083A (en) | Improvement in amplifiers for audio frequencies and method of deriving feedback voltages, useful for making sound records and other purposes | |
GB209345A (en) | Transformers for audio frequency amplifiers and the like | |
GB480318A (en) | Improvements in and relating to electric transformers | |
GB675435A (en) | Improvements in or relating to magnetic sound recording methods |