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 mixtureInfo
- 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
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.
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)
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 |
-
1936
- 1936-09-11 GB GB24840/36A patent/GB478605A/en not_active Expired
Cited By (4)
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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