[go: up one dir, main page]

GB580738A - Improvements in or relating to signal transmission systems employing phase or frequency modulation - Google Patents

Improvements in or relating to signal transmission systems employing phase or frequency modulation

Info

Publication number
GB580738A
GB580738A GB658943A GB658943A GB580738A GB 580738 A GB580738 A GB 580738A GB 658943 A GB658943 A GB 658943A GB 658943 A GB658943 A GB 658943A GB 580738 A GB580738 A GB 580738A
Authority
GB
United Kingdom
Prior art keywords
signal
pulses
frequency
amplifier
modulation
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
GB658943A
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
Priority to BE469241D priority Critical patent/BE469241A/xx
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to GB658943A priority patent/GB580738A/en
Priority to FR933084D priority patent/FR933084A/en
Publication of GB580738A publication Critical patent/GB580738A/en
Priority to ES0176098A priority patent/ES176098A1/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K7/00—Modulating pulses with a continuously-variable modulating signal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B14/00—Transmission systems not characterised by the medium used for transmission
    • H04B14/02—Transmission systems not characterised by the medium used for transmission characterised by the use of pulse modulation

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Amplitude Modulation (AREA)
  • Transmitters (AREA)

Abstract

580,738. Frequency and phase modulation. STANDARD TELEPHONES & CABLES, Ltd., and SCULLY, C. T. April 23, 1943, No. 6589. [Class 40 (v)] A phase or frequency modulated carrier wave is generated by first applying the signal to modulate unsymmetrically the duration of repetitive pulses, and then extracting (e.g. by filtering) one of the harmonics of the pulse train to serve as the modulated' carrier, amplitude modulation being removed by controlling the gain of an amplifier. Preferably, the asymmetry of modulation is effected by maintaining either the leading or lagging edge of the pulses unaffected by the signal. Amplitude modulation present in the carrier is removed by automatic control of amplification ; but the amount of such amplitude modulation may be reduced by suitable choice of the width ratio, i.e. the ratio of normal pulse duration to the repetitive period of the pulses. In Fig. 4, the signal source SS is coupled through a network SN to a pulse generator PG from which modulated pulses are fed through an amplifier A to a filter F by which a desired harmonic is selected. The signal is also applied through a rectifier R to increase the gain of the amplifier A as the signal amplitude rises. The amplifier may be placed after the filter and its gain regulated by rectifying the filter output. The network SN is omitted when phase modulation is desired, but for a frequency-modulated output the network should be designed to attenuate signal voltages of higher frequency. The pulse generator may comprise a cascade pair of valves V1, V2 with the signal applied to the grid of V1 in series with a saw-tooth voltage from the source RO, the grid being back-biassed by a source B1. The valve V1 is thus opened for periods depending on the signal voltage, and substantially square-topped pulses are derived from the anode of the valve V2, the pulses being of varying duration with one edge fixed. Preferably, a high harmonic of the pulse frequency is chosen, as it then contains a deeper phase modulation ; moreover, less multiplication of frequency is required.
GB658943A 1943-04-23 1943-04-23 Improvements in or relating to signal transmission systems employing phase or frequency modulation Expired GB580738A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE469241D BE469241A (en) 1943-04-23
GB658943A GB580738A (en) 1943-04-23 1943-04-23 Improvements in or relating to signal transmission systems employing phase or frequency modulation
FR933084D FR933084A (en) 1943-04-23 1946-08-29 Improvements to electric pulse transmission systems
ES0176098A ES176098A1 (en) 1943-04-23 1946-12-14 IMPROVEMENTS OR IN RELATED TO ELECTRICAL IMPLUSES TRANSMISSION SYSTEMS

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB658943A GB580738A (en) 1943-04-23 1943-04-23 Improvements in or relating to signal transmission systems employing phase or frequency modulation

Publications (1)

Publication Number Publication Date
GB580738A true GB580738A (en) 1946-09-18

Family

ID=9817238

Family Applications (1)

Application Number Title Priority Date Filing Date
GB658943A Expired GB580738A (en) 1943-04-23 1943-04-23 Improvements in or relating to signal transmission systems employing phase or frequency modulation

Country Status (4)

Country Link
BE (1) BE469241A (en)
ES (1) ES176098A1 (en)
FR (1) FR933084A (en)
GB (1) GB580738A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2867763A (en) * 1954-08-03 1959-01-06 Siemens Ag System for controlling or regulating an electric motor by pulses of variable pulsing ratio

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2867763A (en) * 1954-08-03 1959-01-06 Siemens Ag System for controlling or regulating an electric motor by pulses of variable pulsing ratio

Also Published As

Publication number Publication date
BE469241A (en)
ES176098A1 (en) 1947-01-16
FR933084A (en) 1948-04-09

Similar Documents

Publication Publication Date Title
ES483999A1 (en) Switched-mode voltage converter
GB592414A (en) Pulse modulation system
GB1468750A (en) Regulation and stabilizing in a switching power supply
GB596078A (en) Improvements in or relating to arrangements for demodulating time modulated electricpulses
GB984567A (en) Inverter system
GB1187491A (en) Improvements in Correlators
GB600244A (en) Push pull pulse modulation system
GB580738A (en) Improvements in or relating to signal transmission systems employing phase or frequency modulation
GB601135A (en) Electric pulse modulating systems
GB628555A (en) Improvements in or relating to signalling systems employing pulse-width modulation
GB819647A (en) Improvements in or relating to circuit-arrangements for automatic frequency stabilization of an oscillator relative to the frequency of a pilot wave
GB745115A (en) Improvements in or relating to frequency-modulation radio-wave transmission systems
GB611392A (en) Improvements in and relating to pulse generators
GB1294940A (en)
GB1505829A (en) Pulse modulated amplifiers
GB1248209A (en) Improvements in or relating to modulation systems
GB938382A (en) F.m. modulator with a.f.c.
GB586098A (en) Improvements in or relating to electric full-wave rectifiers
GB592584A (en) Improvements in pulse modulation systems
SE320727B (en)
JPS57111121A (en) Pulse width modulating method and its circuit by negative feedback circuit configuration
GB596638A (en) Improvements in or relating to the generation of electric pulses
GB606780A (en) Frequency modulation system for electric signalling
GB503443A (en) Modulating arrangements for high frequency signalling systems
JPS5531328A (en) Modulator