CA1218746A - Detecting the presence of a first varying signal in the presence of a second varying signal - Google Patents
Detecting the presence of a first varying signal in the presence of a second varying signalInfo
- Publication number
- CA1218746A CA1218746A CA000466644A CA466644A CA1218746A CA 1218746 A CA1218746 A CA 1218746A CA 000466644 A CA000466644 A CA 000466644A CA 466644 A CA466644 A CA 466644A CA 1218746 A CA1218746 A CA 1218746A
- Authority
- CA
- Canada
- Prior art keywords
- signal
- level
- components
- detecting
- output signal
- 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
- 230000003247 decreasing effect Effects 0.000 claims abstract 3
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
- G10L25/00—Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00
- G10L25/78—Detection of presence or absence of voice signals
Landscapes
- Engineering & Computer Science (AREA)
- Computational Linguistics (AREA)
- Signal Processing (AREA)
- Health & Medical Sciences (AREA)
- Audiology, Speech & Language Pathology (AREA)
- Human Computer Interaction (AREA)
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Noise Elimination (AREA)
Abstract
Abstract of the Disclosure A technique is disclosed for detecting the presence of larger amplitude signals in a signal having both smaller and larger amplitudes. The signal is peak detected, after which the valleys of the peak detected signal are valley detected to provide a valley detected signal. The level of the basic signal relative to the valley detected signal is altered by decreasing the former or increasing the latter, e.g., by a ratio of 1:2 or 2:1 respectively, and the resulting signals are compared to produce an output when the level of the former exceeds the level of the latter. The technique can be used in a hands-free communication system to detect voice signals in a signal containing both noise and voice signals.
Claims (6)
1. Apparatus for processing a signal containing first and second components the amplitudes of which both vary, the first components from time-to-time having greater amplitudes than that of the second components, to detect the presence of the first components comprising means for peak detecting said signal, said peak detecting means having an output terminal and providing at said output terminal a peak detected output signal having a level proportional to the maximum level of said signal; means connected to said output terminal for valley detecting the valleys of said peak detected output signal to produce a valley detected output signal having a level proportional to the lowest level of said peak detected output signal; means for relatively decreasing the level of said signal containing said first and second components relative to the level of said valley detected output signal; and means for comparing the levels of the two last-mentioned signals to produce an output signal when the level of the first of the two last-mentioned signals exceeds the level of the second of the two last-mentioned signals.
2. Apparatus according to claim 1 wherein said means for relatively decreasing comprises means for attenuating said signal containing said first and second components.
3. Apparatus according to claim 1 wherein said means for attenuating attenuates said signal containing said first and second components by about one half.
4. Apparatus according to claim 1 wherein said means for comparing is a comparator.
5. Apparatus according to claim 1 wherein said detecting means each include an operational amplifier.
6. Apparatus according to claim 5 wherein each said operational amplifier is connected to function essentially as an ideal diode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000466644A CA1218746A (en) | 1984-10-30 | 1984-10-30 | Detecting the presence of a first varying signal in the presence of a second varying signal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000466644A CA1218746A (en) | 1984-10-30 | 1984-10-30 | Detecting the presence of a first varying signal in the presence of a second varying signal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1218746A true CA1218746A (en) | 1987-03-03 |
Family
ID=4129037
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000466644A Expired CA1218746A (en) | 1984-10-30 | 1984-10-30 | Detecting the presence of a first varying signal in the presence of a second varying signal |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1218746A (en) |
-
1984
- 1984-10-30 CA CA000466644A patent/CA1218746A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |