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
Application number
GB2457667A
Inventor
Robert Walter Alister Scarr
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
STC PLC
Original Assignee
Standard Telephone and Cables PLC
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to GB2457667A priority Critical patent/GB1164386A/en
Publication of GB1164386A publication Critical patent/GB1164386A/en
Expired legal-status Critical Current

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.
GB2457667A 1967-05-26 1967-05-26 Frequency Separation. Expired GB1164386A (en)

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)

* Cited by examiner, † Cited by third party
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

Cited By (5)

* Cited by examiner, † Cited by third party
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

Similar Documents

Publication Publication Date Title
GB1221890A (en) Multifrequency tone detector
ES398233A1 (en) Multi frequency receiver
GB1164386A (en) Frequency Separation.
GB1105427A (en)
ATA798572A (en) CIRCUIT ARRANGEMENT FOR THE TRANSMISSION OF PCM SIGNALS OF A PCM TIME MULTIPLEX REMOTE NETWORK UNDER RUN TIME EQUIPMENT
JPS52136503A (en) Noise suppession circuit
IT956223B (en) CIRCUIT ARRANGEMENT FOR TELEPHONE SYSTEMS WITH INDUCTIVE COUPLING OF ACOUSTIC SIGNALS
JPS51113518A (en) Multifrequency signal receiver
BE763497A (en) COMMUNICATION FOR THE TRANSMISSION OF A WIDEBAND SIGNAL FROM A TRANSMITTER TO A RECEIVER
JPS5235503A (en) Stop ring circuit for telephone bell ring
GB701738A (en) Improvements in or relating to telecommunication exchange systems
FR2268406A1 (en) Double frequency telephone signalling - recognises signal for set frequency voltage relationship
GB1176448A (en) Improvements in or relating to Voice Frequency Signalling Systems
JPS5250143A (en) Multi-stage focusing equipment
AU163006B2 (en) Voice frequency signaling circuit
ZA706171B (en) Frequency-selective signal receiver
JPS523318A (en) Howler circuit
CA812953A (en) Amplitude discriminator circuit arrangements
JPS5224427A (en) Frequency converter circuit
AU1582453A (en) Voice frequency signaling circuit
SE397461B (en) FREQUENCY SELECTIVE SIGNAL RECEIVER FOR TELECOMMUNICATIONS
JPS51123504A (en) Signal identification circuit
JPS51113519A (en) Multifrequency signal receiver
JPS5422101A (en) Stereo modulation equipment
CA499774A (en) Voice frequency signaling circuit

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