US2300436A - Phase modulation - Google Patents

Phase modulation Download PDF

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Publication number
US2300436A
US2300436A US423744A US42374441A US2300436A US 2300436 A US2300436 A US 2300436A US 423744 A US423744 A US 423744A US 42374441 A US42374441 A US 42374441A US 2300436 A US2300436 A US 2300436A
Authority
US
United States
Prior art keywords
grid
phase
anode
carrier
deflecting
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 - Lifetime
Application number
US423744A
Other languages
English (en)
Inventor
Albert M Skellett
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.)
AT&T Corp
Original Assignee
Bell Telephone Laboratories Inc
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 BE475489D priority Critical patent/BE475489A/xx
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US423744A priority patent/US2300436A/en
Application granted granted Critical
Publication of US2300436A publication Critical patent/US2300436A/en
Priority to FR950443D priority patent/FR950443A/fr
Priority to GB21765/47A priority patent/GB625530A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K7/00—Modulating pulses with a continuously-variable modulating signal
    • H03K7/04—Position modulation, i.e. PPM

Definitions

  • the modulating device of the invention consists of a focussed cathode ray or electron beam tube in which there is interposed in the path of the beam a shield plate having a narrow slot like aperture so placed that the beam can pass to the target anode only when it is in its undeflected position.
  • the tube is provided also with beam deflecting means upon which the input oscillations, carrier and signal, may be impressed.
  • the deflecting means is subject to the influence of a high frequency sinusoidal oscillation the beam is caused to swing laterally in synchronism with the oscillation so that it traverses the aperture in the shield plate at the instants of zero intensity of the oscillation.
  • FIG. 1 is a circuit schematic of a modulating system embodying the invention.
  • ill is a cathode ray or electron beam tube the electrodes of which comprise an indirectly heated cathode II, the heater circuit of which is not shown, an apertured anode l2, 9. target anode l3, a shield l8 having a single narrow aperture running parallel to the axis of the cathode, a grid l5 located between shield It and target 13, and electrostatic deflecting plates l6 and I1. Focussing of the electron stream is effected by means of a magnet l8 so disposed in relation to the tube that the field between its iii poles is parallel to the central axis of the electrodes. I
  • Cathode II is grounded and is connected to anode l2 through battery l9, or other convenient source of direct current, which establishes an electron stream directed generally towards target l3.
  • An output circuit connected to target l3 comprises a tuned transformer 20 and a direct current source 2
  • Deflecting plates l6 and I1 constitute the input electrodes of the vacuum tube' and are connected to the input circuit by leads 22 and 23.
  • the input circuit which is balanced with respect to ground potential, includes a tuned high frequency transformer comprising a primary winding 24, to
  • Grid I5 is coupled to one side of the input circuit through a phase shifting network comprising condenser 34 and resistance 35, one terminal of which is grounded.
  • the purpose of this phase shifter is to ensure that the carrier frequency potential between grid l5 and ground is substantially in quadrature with the carrier frequency potential between the deflecting plates or between either plate and ground.
  • condenser 34 should have a substantially higher impedance than resistance 35. at the carrier frequency and should be of sufliciently low capacity so that the balance of the input circuit is not seriously disturbed. If need be the circuit.
  • balance may be maintained by the connection of a similar condenser and resistance combina- 7 tion between plate I! and ground.
  • the method 01' phase modulation which comprises producing a complex omillation by the superposition of signal oscillations upon high frequency sinusoidal oscillations of substantially greater amplitude, controlling the deflection of a iocussed beam of electrons in accordance with the complex oscillation, deriving a train of cur-' rent impulses synchronous with the instants of zero intensity of the complex oscillation by intercepting the swinging electron beam at its undeflected position, and periodically retarding the tions on high frequency sinusoidal rscillations of 4 substantially greater amplitude, means producing a foscussed electron beam, an anode disposed in the path of the beam so as to receive electrons only when thebeam is in its undeflected position, an output circuit connected to said anode means for deflecting the beam in accordance with the complex oscillation whereby current impulses synchronous with the instants of zero value of the complex oscillation are produced in said output circuit, and means for periodically retarding the electrons of the beam to suppress alternate current impulses.
  • Phase modulating apparatus comprising mean producing a focussed electron beam, means for deflecting the beam from a central path in accordance with the instantaneous value or superposed carrier and signal oscillations, an anode located in the central path of the beam, an output circuit connected to said anode, a shield plate in front of said anode, said shield plate having an aperture therein so located that the beam can pass to the anode only in its undeflected position, a grid interposed between said shield and" said anode, and means for energizing said grid with a potential substantially in phase quadrature with the deflection o1 thebeam.

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  • Particle Accelerators (AREA)
US423744A 1941-12-20 1941-12-20 Phase modulation Expired - Lifetime US2300436A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE475489D BE475489A (en:Method) 1941-12-20
US423744A US2300436A (en) 1941-12-20 1941-12-20 Phase modulation
FR950443D FR950443A (fr) 1941-12-20 1947-07-29 Modulation de phase
GB21765/47A GB625530A (en) 1941-12-20 1947-08-07 Improvements in or relating to phase modulating apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US423744A US2300436A (en) 1941-12-20 1941-12-20 Phase modulation

Publications (1)

Publication Number Publication Date
US2300436A true US2300436A (en) 1942-11-03

Family

ID=23680016

Family Applications (1)

Application Number Title Priority Date Filing Date
US423744A Expired - Lifetime US2300436A (en) 1941-12-20 1941-12-20 Phase modulation

Country Status (4)

Country Link
US (1) US2300436A (en:Method)
BE (1) BE475489A (en:Method)
FR (1) FR950443A (en:Method)
GB (1) GB625530A (en:Method)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2460966A (en) * 1945-02-05 1949-02-08 Zenith Radio Corp Communications system
US2550772A (en) * 1947-12-23 1951-05-01 Radio Electr Soc Fr Frequency-modulated wave generator
US2553566A (en) * 1946-10-07 1951-05-22 Farnsworth Res Corp Phase modulated wave generator
US2565410A (en) * 1944-09-20 1951-08-21 Philco Corp Controllable electrical delay means
US2638539A (en) * 1949-05-28 1953-05-12 Rca Corp Apparatus for converting electrical frequency variations into amplitude variations
US2684449A (en) * 1946-03-19 1954-07-20 Raytheon Mfg Co Commutator tube
US2821632A (en) * 1944-09-25 1958-01-28 Byron T Wright Apparatus for producing ions of vaporizable materials
US2975359A (en) * 1957-12-04 1961-03-14 Friedrich M O Foerster Electrical apparatus

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2565410A (en) * 1944-09-20 1951-08-21 Philco Corp Controllable electrical delay means
US2821632A (en) * 1944-09-25 1958-01-28 Byron T Wright Apparatus for producing ions of vaporizable materials
US2460966A (en) * 1945-02-05 1949-02-08 Zenith Radio Corp Communications system
US2684449A (en) * 1946-03-19 1954-07-20 Raytheon Mfg Co Commutator tube
US2553566A (en) * 1946-10-07 1951-05-22 Farnsworth Res Corp Phase modulated wave generator
US2550772A (en) * 1947-12-23 1951-05-01 Radio Electr Soc Fr Frequency-modulated wave generator
US2638539A (en) * 1949-05-28 1953-05-12 Rca Corp Apparatus for converting electrical frequency variations into amplitude variations
US2975359A (en) * 1957-12-04 1961-03-14 Friedrich M O Foerster Electrical apparatus

Also Published As

Publication number Publication date
BE475489A (en:Method)
FR950443A (fr) 1949-09-27
GB625530A (en) 1949-06-29

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