GB1342799A - Method of and device for enhancing marine navigational sound signals in the presence of acoustic noise - Google Patents
Method of and device for enhancing marine navigational sound signals in the presence of acoustic noiseInfo
- Publication number
- GB1342799A GB1342799A GB1737071A GB1737071A GB1342799A GB 1342799 A GB1342799 A GB 1342799A GB 1737071 A GB1737071 A GB 1737071A GB 1737071 A GB1737071 A GB 1737071A GB 1342799 A GB1342799 A GB 1342799A
- Authority
- GB
- United Kingdom
- Prior art keywords
- signals
- slope
- noise
- amplifier
- 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
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/001—Acoustic presence detection
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G9/00—Combinations of two or more types of control, e.g. gain control and tone control
- H03G9/02—Combinations of two or more types of control, e.g. gain control and tone control in untuned amplifiers
- H03G9/04—Combinations of two or more types of control, e.g. gain control and tone control in untuned amplifiers having discharge tubes
- H03G9/10—Combinations of two or more types of control, e.g. gain control and tone control in untuned amplifiers having discharge tubes for tone control and volume expansion or compression
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S367/00—Communications, electrical: acoustic wave systems and devices
- Y10S367/901—Noise or unwanted signal reduction in nonseismic receiving system
Abstract
1342799 Selective amplification of sound signals SPERRY RAND CORP 27 May 1971 [19 June 1970] 17370/71 Heading H4J Detection of information signals (e.g. fog signals) in the presence of noise signals (e.g. marine acoustic noise) is assisted by converting the information and noise signals into electrical signals and amplifying the electrical signals by an amplifier having a gain versus frequency characteristic adjusted to have a slope opposite to the slope of the amplitude versus frequency characteristic of the noise signal. The electrical noise signals of frequency lower than the lowest frequency of the information signals are filtered out and the remaining signals are utilized, e.g. by a recorder and headphones or a loud-speaker. A typical ship's background noise due to bow wake, ship's engine, machinery, &c. varies in a fairly regular manner from 31À5 to 4,000 Hz with a negative slope of 6 db. per octave (Fig. 1, not shown, the region between 31À5 and 125 Hz being of particularly high intensity. Fog warning sounds produced by ship's bells, horns and whistles are in the frequency range 125 to 4000 Hz (Fig. 3, not shown). A circuit (Fig. 4) makes use of these facts. A cardioid microphone 11 supplies a preamplifier 12 whose gain is adjustable by a control 13 but has a slope lying between 4 and 8 db. per octave, preferably 6 db. per octave. The output of the preamplifier is applied to a filter network 14 having a low frequency cut-off control 15 and a high frequency cut-off control 16. The response of the preamplifier 12 and filter network 14 is bounded by the curves 100 and 102 (Fig. 3) and is typically the curve 101 having a rising slope of 6 db. per octave in portion BC. The output of the filter network 14 is supplied to a compression amplifier 17, controlled in conventional manner by an amplifier 19 and rectifier 20. The negative and positive slopes of 6 db. per octave of the noise curve and of the preamplifier, combined with volume compression, allow the ship's lookout to hear all sounds within the information signal frequency range at about the same sound level. The 4 to 8 db. rising portion of the characteristic curve (Fig. 3) is beneficial in detecting navigational sounds emitted by distant sound sources. The lookout wears earphones or listens to a loud-speaker in the shelter of the pilot house, a power amplifier 22 being provided. The preamplifier 12 (Fig. 5) includes a matching transformer 31 and an operational amplifier 12a, having two double ended stages 34, 35 and 41, 42 and a single ended class AB output stage 46, 47. Transistors 48 and 49 respectively co-operate in the first and second stages in determining current flow levels. A damping network 60 having components 61, 62, 63, which may be adjustable, prevents high frequency oscillation. Feedback from the output 50 to the transistor 35 controls the slope gain of the amplifier 12a. Capacitors 51 and 55 are adjusted to give the desired (e.g. 6 db. per octave) increase in gain with frequency. Variable resistors 54 and 56 are overall gain-determining resistors, and may be gang controlled. Circuit 12b is an emitter-follower circuit.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US4943870A | 1970-06-19 | 1970-06-19 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1342799A true GB1342799A (en) | 1974-01-03 |
Family
ID=21959818
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1737071A Expired GB1342799A (en) | 1970-06-19 | 1971-05-27 | Method of and device for enhancing marine navigational sound signals in the presence of acoustic noise |
Country Status (4)
Country | Link |
---|---|
US (1) | US3685009A (en) |
JP (1) | JPS523318B1 (en) |
DE (1) | DE2130342A1 (en) |
GB (1) | GB1342799A (en) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3413561A1 (en) * | 1984-04-11 | 1985-10-24 | Fried. Krupp Gmbh, 4300 Essen | Device for intercepting received audible signals |
US6480610B1 (en) * | 1999-09-21 | 2002-11-12 | Sonic Innovations, Inc. | Subband acoustic feedback cancellation in hearing aids |
US6757395B1 (en) | 2000-01-12 | 2004-06-29 | Sonic Innovations, Inc. | Noise reduction apparatus and method |
US6706966B2 (en) | 2001-03-19 | 2004-03-16 | L-3 Communications Corporation | Hardened voyage data recorder |
US20060083110A1 (en) * | 2004-10-19 | 2006-04-20 | Tietjen Byron W | Ambient bistatic echo ranging system and method |
CN107154256B (en) * | 2017-06-27 | 2023-11-24 | 山东省计算中心(国家超级计算济南中心) | Sound masking system based on sound source positioning and self-adaptive adjusting method |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1987984A (en) * | 1931-11-06 | 1935-01-15 | Rca Corp | Adjacent channel selectivity |
US3588803A (en) * | 1969-03-12 | 1971-06-28 | Sperry Rand Corp | Ship's warning system |
-
1970
- 1970-06-19 US US49438A patent/US3685009A/en not_active Expired - Lifetime
-
1971
- 1971-05-27 GB GB1737071A patent/GB1342799A/en not_active Expired
- 1971-06-10 JP JP46041357A patent/JPS523318B1/ja active Pending
- 1971-06-18 DE DE19712130342 patent/DE2130342A1/en active Pending
Also Published As
Publication number | Publication date |
---|---|
US3685009A (en) | 1972-08-15 |
DE2130342A1 (en) | 1971-12-23 |
JPS523318B1 (en) | 1977-01-27 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed [section 19, patents act 1949] | ||
PLNP | Patent lapsed through nonpayment of renewal fees |