JPS55100774A - Tone detection circuit - Google Patents
Tone detection circuitInfo
- Publication number
- JPS55100774A JPS55100774A JP896379A JP896379A JPS55100774A JP S55100774 A JPS55100774 A JP S55100774A JP 896379 A JP896379 A JP 896379A JP 896379 A JP896379 A JP 896379A JP S55100774 A JPS55100774 A JP S55100774A
- Authority
- JP
- Japan
- Prior art keywords
- inputted
- tone detection
- shift register
- sampled data
- detection circuit
- 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.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
- Data Exchanges In Wide-Area Networks (AREA)
Abstract
PURPOSE:To simplify a tone detection circuit by digitizing, by using ROM for a communication system using a tone signal. CONSTITUTION:Tone signal 1 is inputted to comparator 2 to obtain a binary zero- cross wave. This is sampled by sampling clock 4 from sampling clock generator 9 and its output is inputted to shift register 5. The length of this shift register 5 is the number of samples for finding power. Parallel output 6 of respective bits of shift register 5, namely, a series of sampled data is inputted to the address input terminal of ROM7. Corresponding to all combinations of sampled data serieses, ROM7 is stored with data of ''1'' and ''0'' showing the existence of tone detection and every time one series of sampled data is inputted, corresponding tone detection output 8 is sent out.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP896379A JPS55100774A (en) | 1979-01-29 | 1979-01-29 | Tone detection circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP896379A JPS55100774A (en) | 1979-01-29 | 1979-01-29 | Tone detection circuit |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS55100774A true JPS55100774A (en) | 1980-07-31 |
Family
ID=11707320
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP896379A Pending JPS55100774A (en) | 1979-01-29 | 1979-01-29 | Tone detection circuit |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS55100774A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH04120840A (en) * | 1990-09-12 | 1992-04-21 | Nec Corp | Tone signal detecting circuit |
WO1993015580A1 (en) * | 1992-01-29 | 1993-08-05 | Fujitsu Limited | Circuit for detecting object signal from input signal |
US5406975A (en) * | 1993-03-12 | 1995-04-18 | Aisan Kogyo Kabushiki Kaisha | Flow rate control valve |
-
1979
- 1979-01-29 JP JP896379A patent/JPS55100774A/en active Pending
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH04120840A (en) * | 1990-09-12 | 1992-04-21 | Nec Corp | Tone signal detecting circuit |
WO1993015580A1 (en) * | 1992-01-29 | 1993-08-05 | Fujitsu Limited | Circuit for detecting object signal from input signal |
US5471507A (en) * | 1992-01-29 | 1995-11-28 | Fujitsu Limited | Circuit for detecting object signal from input signal |
US5406975A (en) * | 1993-03-12 | 1995-04-18 | Aisan Kogyo Kabushiki Kaisha | Flow rate control valve |
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