GB478605A - Improvements in and relating to circuit arrangements for filtering out a fluctuating frequency from a frequency mixture - Google Patents

Improvements in and relating to circuit arrangements for filtering out a fluctuating frequency from a frequency mixture

Info

Publication number
GB478605A
GB478605A GB24840/36A GB2484036A GB478605A GB 478605 A GB478605 A GB 478605A GB 24840/36 A GB24840/36 A GB 24840/36A GB 2484036 A GB2484036 A GB 2484036A GB 478605 A GB478605 A GB 478605A
Authority
GB
United Kingdom
Prior art keywords
current
echo
frequency
currents
noise
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
GB24840/36A
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.)
Siemens APP und Maschinen GmbH
Original Assignee
Siemens APP und Maschinen GmbH
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 Siemens APP und Maschinen GmbH filed Critical Siemens APP und Maschinen GmbH
Publication of GB478605A publication Critical patent/GB478605A/en
Expired legal-status Critical Current

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
    • H04B1/06—Receivers
    • H04B1/10—Means associated with receiver for limiting or suppressing noise or interference

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)

Abstract

478,605. Echo distance - measuring apparatus. SIEMENS APPARATE UND MASCHINEN GES. Sept. 11, 1936, No. 24840. Convention date, Oct. 9, 1935. [Class 118 (ii)] [Also in Groups XL and XXXIX] Apparatus for selecting a desired sound or other vibration out of a background of noise or other mixed vibrations comprises a set of filters 3 having contiguous pass bands and provided with current-limiting devices 4 for eliminating noise currents. The invention is applicable to depth-sounding from aeroplanes. In the latter instance the echo is received by a microphone 1 and the sound currents are transmitted through an amplifier 5 to a receiver 6. The pitch of the echo may vary as a result of the Doppler effect and for other reasons, and the total pass band is accordingly widened by tuning the filters 3 to have contiguous pass bands. Attenuating networks 4 are provided for eliminating noise currents, which are at a lower energy level than the current corresponding to the desired sound. In a modification, Fig. 2 (not shown), the threshold at which the current-limiting device acts is automatically varied in accordance with the noise level by means of rectified microphone current. Alternatively the threshold may be adjusted manually.
GB24840/36A 1935-10-09 1936-09-11 Improvements in and relating to circuit arrangements for filtering out a fluctuating frequency from a frequency mixture Expired GB478605A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE478605X 1935-10-09

Publications (1)

Publication Number Publication Date
GB478605A true GB478605A (en) 1938-01-21

Family

ID=6542275

Family Applications (1)

Application Number Title Priority Date Filing Date
GB24840/36A Expired GB478605A (en) 1935-10-09 1936-09-11 Improvements in and relating to circuit arrangements for filtering out a fluctuating frequency from a frequency mixture

Country Status (1)

Country Link
GB (1) GB478605A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2606286A (en) * 1948-12-08 1952-08-05 Rca Corp Interference reducing system
US2999905A (en) * 1958-01-09 1961-09-12 Paul J Malinaric Noise eliminator
FR2431779A1 (en) * 1978-07-07 1980-02-15 Siemens Ag AERIAL RADIO AMPLIFIER CAPABLE OF PROCESSING STRONG SIGNALS
US4540946A (en) * 1980-06-06 1985-09-10 National Research Development Corp. Variable characteristic filters

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2606286A (en) * 1948-12-08 1952-08-05 Rca Corp Interference reducing system
US2999905A (en) * 1958-01-09 1961-09-12 Paul J Malinaric Noise eliminator
FR2431779A1 (en) * 1978-07-07 1980-02-15 Siemens Ag AERIAL RADIO AMPLIFIER CAPABLE OF PROCESSING STRONG SIGNALS
US4540946A (en) * 1980-06-06 1985-09-10 National Research Development Corp. Variable characteristic filters

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