GB1533984A - Electrical circuit arrangements for generating modulation - Google Patents

Electrical circuit arrangements for generating modulation

Info

Publication number
GB1533984A
GB1533984A GB1765975A GB1765975A GB1533984A GB 1533984 A GB1533984 A GB 1533984A GB 1765975 A GB1765975 A GB 1765975A GB 1765975 A GB1765975 A GB 1765975A GB 1533984 A GB1533984 A GB 1533984A
Authority
GB
United Kingdom
Prior art keywords
signal
switch
frequency
modulation
modulating
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
GB1765975A
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.)
Racal Dana Instruments Ltd
Original Assignee
Racal Dana Instruments Ltd
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 Racal Dana Instruments Ltd filed Critical Racal Dana Instruments Ltd
Priority to GB1765975A priority Critical patent/GB1533984A/en
Publication of GB1533984A publication Critical patent/GB1533984A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C5/00—Amplitude modulation and angle modulation produced simultaneously or at will by the same modulating signal
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

1533984 Calibrating measuring instruments RACAL DANA INSTRUMENTS Ltd 7 Jan 1976 [29 April 1975 3 July 1975] 17659/75 and 27972/75 Heading G1U A modulation generating signal includes means for selectively providing an A. M. or F. M. modulated carrier signal, with a calibration means for selectively providing a time varying modulating signal or a fixed modulating signal. The arrangement shown provides a signal having precisely determined levels of frequency or amplitude modulation, for feeding to modulation measuring apparatus (e.g. as disclosed in Specification 1509913) for calibration. For amplitude modulation, the switches 15, 26 and 65 are set as shown. Oscillator 10 is set to a required modulating frequency by switch 12 and the switch 20 set to feed the negative peak signal via attenuator 21 (set at OdB) to the modulating input of amplitude modulator 66. Voltage controlled oscillator 28 is set by control 30 to produce a 0.6MHz signal which is converted in a phase-lock loop 42, 44, 46 to 10.6MHz the signal passing via switch 65 to the carrier input of modulator 66. By adjusting attenuator 14B, the peaks of the modulating signal is adjusted such that the D. C. applied to the modulator represents a level of 100% negative modulation and the output 70 is thus zero. By switching switch 20 to feed the modulating signal direct to attenuator 21, an amplitude modulated 10.6MHz signal is available at output 70, the level of modulation being precisely determined by attenuator 21 (OdB#100%). For frequency modulation, switch 15 is set to 14C, and switch 26 to its other position. Here, the phase-lock loop provides a carrier varying with the frequency of voltage controlled oscillator 28 which is fed with the modulating frequency signal via switch 26. By setting the switch 20 to select negative or positive peaks of the modulating signal, the maximum and minimum excursions of the carrier frequency are set by attenuator 14C and the centre frequency is set by switching 20 to its illustrated position. For either mode, switch 65 may be altered to provide a low value carrier frequency.
GB1765975A 1976-01-07 1976-01-07 Electrical circuit arrangements for generating modulation Expired GB1533984A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1765975A GB1533984A (en) 1976-01-07 1976-01-07 Electrical circuit arrangements for generating modulation

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1765975A GB1533984A (en) 1976-01-07 1976-01-07 Electrical circuit arrangements for generating modulation

Publications (1)

Publication Number Publication Date
GB1533984A true GB1533984A (en) 1978-11-29

Family

ID=10099003

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1765975A Expired GB1533984A (en) 1976-01-07 1976-01-07 Electrical circuit arrangements for generating modulation

Country Status (1)

Country Link
GB (1) GB1533984A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0654914A2 (en) * 1993-11-19 1995-05-24 Victor Company Of Japan, Limited Spread spectrum communication switchable between FSK and PSK
US5539770A (en) * 1993-11-19 1996-07-23 Victor Company Of Japan, Ltd. Spread spectrum modulating apparatus using either PSK or FSK primary modulation

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0654914A2 (en) * 1993-11-19 1995-05-24 Victor Company Of Japan, Limited Spread spectrum communication switchable between FSK and PSK
US5539770A (en) * 1993-11-19 1996-07-23 Victor Company Of Japan, Ltd. Spread spectrum modulating apparatus using either PSK or FSK primary modulation
EP0654914A3 (en) * 1993-11-19 1997-10-08 Victor Company Of Japan Spread spectrum communication switchable between FSK and PSK.

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee