FR2385283A1 - Digital touch-tone recognition circuit - derives PWM signal from analogue signal and compares data with stored value (NL 26.9.78) - Google Patents
Digital touch-tone recognition circuit - derives PWM signal from analogue signal and compares data with stored value (NL 26.9.78)Info
- Publication number
- FR2385283A1 FR2385283A1 FR7807117A FR7807117A FR2385283A1 FR 2385283 A1 FR2385283 A1 FR 2385283A1 FR 7807117 A FR7807117 A FR 7807117A FR 7807117 A FR7807117 A FR 7807117A FR 2385283 A1 FR2385283 A1 FR 2385283A1
- Authority
- FR
- France
- Prior art keywords
- analogue signal
- derives
- stored value
- recognition circuit
- 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.)
- Withdrawn
Links
- 239000002131 composite material Substances 0.000 abstract 1
- 238000001514 detection method Methods 0.000 abstract 1
- 238000000034 method Methods 0.000 abstract 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q1/00—Details of selecting apparatus or arrangements
- H04Q1/18—Electrical details
- H04Q1/30—Signalling arrangements; Manipulation of signalling currents
- H04Q1/44—Signalling arrangements; Manipulation of signalling currents using alternate current
- H04Q1/444—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies
- H04Q1/45—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using multi-frequency signalling
- H04Q1/457—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using multi-frequency signalling with conversion of multifrequency signals into digital signals
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Dc Digital Transmission (AREA)
- Mobile Radio Communication Systems (AREA)
- Radar Systems Or Details Thereof (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
Abstract
A digital processing technique is employed in telecommunications arrangements to eliminate costly steep-slope filters previously necessary for the detection of multitone control signals in the presence of speech signals. The composite analogue signal (a) derived from the individual code tones is converted to a constant amplitude pulse train of which individual pulse lengths correspond to the interval between successive corssing points of the analogue signal. The digital signals so obtained (b) are compared with fixed predetermined digital signals corresponding to the n frequency combinations in the full code range. Since the pulse trains exhibit mirror symmetry of the beat interval, it is necessary only to carry out the comparison for half of this period.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE2712831A DE2712831B2 (en) | 1977-03-23 | 1977-03-23 | Speech-protected, frequency-selective character receiver |
Publications (1)
Publication Number | Publication Date |
---|---|
FR2385283A1 true FR2385283A1 (en) | 1978-10-20 |
Family
ID=6004476
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
FR7807117A Withdrawn FR2385283A1 (en) | 1977-03-23 | 1978-03-13 | Digital touch-tone recognition circuit - derives PWM signal from analogue signal and compares data with stored value (NL 26.9.78) |
Country Status (6)
Country | Link |
---|---|
JP (1) | JPS53117903A (en) |
DE (1) | DE2712831B2 (en) |
FR (1) | FR2385283A1 (en) |
IT (1) | IT1093892B (en) |
NL (1) | NL7803090A (en) |
SE (1) | SE7803253L (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0081294A2 (en) * | 1981-11-06 | 1983-06-15 | Electronics Corporation Of Israel Limited | Tone detector |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DD259987A3 (en) * | 1986-07-07 | 1988-09-14 | Rft Nachrichtenelektronik Albe | METHOD AND ARRANGEMENT FOR LANGUAGE PROTECTION IN MFC-TASTWAHLMPFAENGERN |
DD266253A3 (en) * | 1987-06-22 | 1989-03-29 | Leipzig Rft Nachrichtenelekt | UNIVERSAL DIGITAL MFC RECEPTIONER |
-
1977
- 1977-03-23 DE DE2712831A patent/DE2712831B2/en active Granted
-
1978
- 1978-03-13 FR FR7807117A patent/FR2385283A1/en not_active Withdrawn
- 1978-03-21 SE SE7803253A patent/SE7803253L/en unknown
- 1978-03-22 NL NL7803090A patent/NL7803090A/en not_active Application Discontinuation
- 1978-03-22 IT IT21481/78A patent/IT1093892B/en active
- 1978-03-23 JP JP3356778A patent/JPS53117903A/en active Pending
Non-Patent Citations (1)
Title |
---|
EXBK/77 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0081294A2 (en) * | 1981-11-06 | 1983-06-15 | Electronics Corporation Of Israel Limited | Tone detector |
EP0081294A3 (en) * | 1981-11-06 | 1984-05-16 | Electronics Corporation Of Israel Limited | Tone detector |
Also Published As
Publication number | Publication date |
---|---|
DE2712831A1 (en) | 1978-10-05 |
NL7803090A (en) | 1978-09-26 |
IT1093892B (en) | 1985-07-26 |
JPS53117903A (en) | 1978-10-14 |
DE2712831C3 (en) | 1980-09-25 |
DE2712831B2 (en) | 1980-01-24 |
IT7821481A0 (en) | 1978-03-22 |
SE7803253L (en) | 1978-09-24 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
ST | Notification of lapse |