FR548289A - Telephone microphones - Google Patents

Telephone microphones

Info

Publication number
FR548289A
FR548289A FR548289DA FR548289A FR 548289 A FR548289 A FR 548289A FR 548289D A FR548289D A FR 548289DA FR 548289 A FR548289 A FR 548289A
Authority
FR
France
Prior art keywords
telephone microphones
microphones
telephone
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
Application number
Other languages
French (fr)
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
DICTOGRAPH PRODUCTS CORP
Original Assignee
DICTOGRAPH PRODUCTS CORP
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by DICTOGRAPH PRODUCTS CORP filed Critical DICTOGRAPH PRODUCTS CORP
Application granted granted Critical
Publication of FR548289A publication Critical patent/FR548289A/en
Expired legal-status Critical Current

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
    • H04R21/00—Variable-resistance transducers
    • H04R21/02—Microphones
    • H04R21/021—Microphones with granular resistance material

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Details Of Audible-Bandwidth Transducers (AREA)
  • Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
  • Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
  • Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
FR548289D 1921-04-14 1922-03-07 Telephone microphones Expired FR548289A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US461283A US1551723A (en) 1921-04-14 1921-04-14 Transmitter

Publications (1)

Publication Number Publication Date
FR548289A true FR548289A (en) 1923-01-11

Family

ID=9738041

Family Applications (1)

Application Number Title Priority Date Filing Date
FR548289D Expired FR548289A (en) 1921-04-14 1922-03-07 Telephone microphones

Country Status (4)

Country Link
US (1) US1551723A (en)
DE (1) DE379111C (en)
FR (1) FR548289A (en)
GB (1) GB190655A (en)

Also Published As

Publication number Publication date
DE379111C (en) 1923-08-14
US1551723A (en) 1925-09-01
GB190655A (en) 1922-12-28

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