GB1164386A - Frequency Separation. - Google Patents
Frequency Separation.Info
- Publication number
- GB1164386A GB1164386A GB2457667A GB2457667A GB1164386A GB 1164386 A GB1164386 A GB 1164386A GB 2457667 A GB2457667 A GB 2457667A GB 2457667 A GB2457667 A GB 2457667A GB 1164386 A GB1164386 A GB 1164386A
- Authority
- GB
- United Kingdom
- Prior art keywords
- frequency
- group
- frequencies
- zero
- separated
- 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
- 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
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/10—Frequency-modulated carrier systems, i.e. using frequency-shift keying
- H04L27/14—Demodulator circuits; Receiver circuits
- H04L27/144—Demodulator circuits; Receiver circuits with demodulation using spectral properties of the received signal, e.g. by using frequency selective- or frequency sensitive elements
- H04L27/148—Demodulator circuits; Receiver circuits with demodulation using spectral properties of the received signal, e.g. by using frequency selective- or frequency sensitive elements using filters, including PLL-type filters
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/10—Frequency-modulated carrier systems, i.e. using frequency-shift keying
- H04L27/14—Demodulator circuits; Receiver circuits
- H04L27/156—Demodulator circuits; Receiver circuits with demodulation using temporal properties of the received signal, e.g. detecting pulse width
- H04L27/1563—Demodulator circuits; Receiver circuits with demodulation using temporal properties of the received signal, e.g. detecting pulse width using transition or level detection
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
Abstract
1,164,386. Automatic exchange systems; voice frequency signalling. STANDARD TELEPHONES & CABLES Ltd. 26 May, 1967, No. 24576/67. Headings H4K and H4R. To detect a frequency combination comprising one frequency from a higher frequency group and one from a lower frequency group each frequency is emphasized with respect to the other to obtain the frequencies in separate channels, the presence of such a frequency in each channel being determined by counting the number of zero-crossings or by measuring the distances between zero-crossing points. The arrangement is suited to production as a solid state circuit. The frequencies of one group are separated from the frequencies of the other group by attenuation of each group relative to the other. The separated signals may be amplitude limited before the zero-crossing patterns are investigated.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2457667A GB1164386A (en) | 1967-05-26 | 1967-05-26 | Frequency Separation. |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2457667A GB1164386A (en) | 1967-05-26 | 1967-05-26 | Frequency Separation. |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1164386A true GB1164386A (en) | 1969-09-17 |
Family
ID=10213828
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB2457667A Expired GB1164386A (en) | 1967-05-26 | 1967-05-26 | Frequency Separation. |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB1164386A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4061885A (en) * | 1975-12-17 | 1977-12-06 | Motorola, Inc. | Digital tone decoder |
FR2478901A1 (en) * | 1980-03-18 | 1981-09-25 | Jeumont Schneider | HIGHER AMPLITUDE ALTERNATING SIGNAL SELECTION STAGE AMONG TWO DIFFERENT FREQUENCY SIGNALS |
-
1967
- 1967-05-26 GB GB2457667A patent/GB1164386A/en not_active Expired
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4061885A (en) * | 1975-12-17 | 1977-12-06 | Motorola, Inc. | Digital tone decoder |
FR2478901A1 (en) * | 1980-03-18 | 1981-09-25 | Jeumont Schneider | HIGHER AMPLITUDE ALTERNATING SIGNAL SELECTION STAGE AMONG TWO DIFFERENT FREQUENCY SIGNALS |
WO1981002714A1 (en) * | 1980-03-18 | 1981-10-01 | Jeumont Schneider | Selection stage of the ac signal having the greater amplitude |
DE3140626C1 (en) * | 1980-03-18 | 1984-03-08 | Jeumont-Schneider, 92811 Puteaux | Circuit arrangement for the selection of an electrical alternating signal |
US4488238A (en) * | 1980-03-18 | 1984-12-11 | Jeumont-Schneider Corporation | Selection stage of the AC signal of greater amplitude between two signals of different frequencies |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
435 | Patent endorsed 'licences of right' on the date specified (sect. 35/1949) | ||
PCNP | Patent ceased through non-payment of renewal fee |