GB1529851A - Frequency-signalling circuit for a telephone - Google Patents

Frequency-signalling circuit for a telephone

Info

Publication number
GB1529851A
GB1529851A GB120375A GB120375A GB1529851A GB 1529851 A GB1529851 A GB 1529851A GB 120375 A GB120375 A GB 120375A GB 120375 A GB120375 A GB 120375A GB 1529851 A GB1529851 A GB 1529851A
Authority
GB
United Kingdom
Prior art keywords
frequencies
division
dividers
interleaved
pulse trains
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
GB120375A
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.)
GEN INSTR MICROELECT
Original Assignee
GEN INSTR MICROELECT
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 GEN INSTR MICROELECT filed Critical GEN INSTR MICROELECT
Priority to GB120375A priority Critical patent/GB1529851A/en
Priority to DE19762600606 priority patent/DE2600606C2/en
Priority to CA243,288A priority patent/CA1031462A/en
Priority to SE7600157A priority patent/SE416100B/en
Priority to FR7600633A priority patent/FR2297526A1/en
Publication of GB1529851A publication Critical patent/GB1529851A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/26—Devices for calling a subscriber
    • H04M1/30—Devices which can set up and transmit only one digit at a time
    • H04M1/50—Devices which can set up and transmit only one digit at a time by generating or selecting currents of predetermined frequencies or combinations of frequencies
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/26—Devices for calling a subscriber
    • H04M1/30—Devices which can set up and transmit only one digit at a time
    • H04M1/50—Devices which can set up and transmit only one digit at a time by generating or selecting currents of predetermined frequencies or combinations of frequencies
    • H04M1/505—Devices which can set up and transmit only one digit at a time by generating or selecting currents of predetermined frequencies or combinations of frequencies signals generated in digital form
    • 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
    • H04Q1/4575—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 which are transmitted in digital form

Abstract

1529851 Waveform generators GENERAL INSTRUMENT MICROELECTRONICS Ltd 8 Jan 1976 [10 Jan 1975] 1203/75 Heading H3H [Also in Division G4] In a 2 out of 8 tone generator, clock pulses are frequency divided in dividers 3A, 3B whose division ratios are set in accordance with respective ones of the 2 frequencies to be generated, the divided clock pulses are fed to stochastic conversion means which produces respective pulse trains whose repetition frequencies vary at the respective frequencies and these are then interleaved in time and filtered to produce the desired 2 out of 8 tone signal. In Figs. 1A, 1B, a keyboard (not shown) marks one of leads 13A and one of leads 13B to set the division ratios of dividers 3A, 3B. For some frequencies, non-integral division is used, this being achieved by varying an integral division factor by unity for alternate cycles, Fig. 3 (not shown). The outputs of the dividers are fed to respective sine-wave value generators 4A, 4B which produce sequences of 3-bit binary numbers: 6, 3, 1, 0, 1, 3, 6 and positive and negative half cycle signals to respective comparators 6A, 6B, receiving 4-bit pseudo-random signals from a noise generator 8, and outputting respective stochastic pulse trains whose instantaneous frequencies vary in an approximately sinusoidal manner at the desired 2 of 8 frequencies. These pulse trains are interleaved in circuit 9, Fig. 12 (not shown) which includes means for varying the proportions in which the trains are interleaved to provide adjustable preemphasis for the higher frequency. Details of all the circuit blocks and frequencies are given.
GB120375A 1975-01-10 1975-01-10 Frequency-signalling circuit for a telephone Expired GB1529851A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
GB120375A GB1529851A (en) 1975-01-10 1975-01-10 Frequency-signalling circuit for a telephone
DE19762600606 DE2600606C2 (en) 1975-01-10 1976-01-09 Circuit arrangement for generating multi-frequency dialing signals in telephone terminals
CA243,288A CA1031462A (en) 1975-01-10 1976-01-09 Frequency-signalling circuit for a telephone
SE7600157A SE416100B (en) 1975-01-10 1976-01-09 CIRCUIT FOR DIGITAL SYNTHETIZATION OF A SIGNAL CONSISTING OF M OVERLAYED WAVE FORMS WITH DIFFERENT FREQUENCIES
FR7600633A FR2297526A1 (en) 1975-01-10 1976-01-12 MULTI-FREQUENCY TELEPHONE CALL CIRCUIT

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB120375A GB1529851A (en) 1975-01-10 1975-01-10 Frequency-signalling circuit for a telephone

Publications (1)

Publication Number Publication Date
GB1529851A true GB1529851A (en) 1978-10-25

Family

ID=9717956

Family Applications (1)

Application Number Title Priority Date Filing Date
GB120375A Expired GB1529851A (en) 1975-01-10 1975-01-10 Frequency-signalling circuit for a telephone

Country Status (5)

Country Link
CA (1) CA1031462A (en)
DE (1) DE2600606C2 (en)
FR (1) FR2297526A1 (en)
GB (1) GB1529851A (en)
SE (1) SE416100B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2121627A (en) * 1982-06-02 1983-12-21 Plessey Co Plc Direct digital synthesiser

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2452823A1 (en) * 1979-03-30 1980-10-24 Texas Instruments France LF signal generator - is esp. for telephone systems and maintains HF stability by using ceramic oscillator
DE69610576T2 (en) * 1995-05-19 2001-05-31 Matsushita Electric Works Ltd Electric shaver cutting unit

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL7008014A (en) * 1969-06-02 1970-12-04
US3820028A (en) * 1971-08-27 1974-06-25 J Thomas Digital tone signal generator
NL160687C (en) * 1972-06-10 1979-11-15 Philips Nv TONE GENERATOR FOR GENERATING SELECTED FREQUENCIES.
US3787836A (en) * 1972-06-15 1974-01-22 Bell Telephone Labor Inc Multitone telephone dialing circuit employing digital-to-analog tone synthesis

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2121627A (en) * 1982-06-02 1983-12-21 Plessey Co Plc Direct digital synthesiser

Also Published As

Publication number Publication date
SE7600157L (en) 1976-07-11
CA1031462A (en) 1978-05-16
DE2600606C2 (en) 1985-06-20
FR2297526A1 (en) 1976-08-06
SE416100B (en) 1980-11-24
FR2297526B1 (en) 1978-05-12
DE2600606A1 (en) 1976-07-15

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Legal Events

Date Code Title Description
PS Patent sealed
PE20 Patent expired after termination of 20 years

Effective date: 19960107