GB1339603A - Phase locked loops - Google Patents

Phase locked loops

Info

Publication number
GB1339603A
GB1339603A GB624071*[A GB1339603DA GB1339603A GB 1339603 A GB1339603 A GB 1339603A GB 1339603D A GB1339603D A GB 1339603DA GB 1339603 A GB1339603 A GB 1339603A
Authority
GB
United Kingdom
Prior art keywords
mixers
phase
frequency
oscillator
producing
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
GB624071*[A
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
Publication of GB1339603A publication Critical patent/GB1339603A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
    • H03L7/00—Automatic control of frequency or phase; Synchronisation
    • H03L7/06—Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop
    • H03L7/08—Details of the phase-locked loop
    • H03L7/10—Details of the phase-locked loop for assuring initial synchronisation or for broadening the capture range
    • H03L7/12—Details of the phase-locked loop for assuring initial synchronisation or for broadening the capture range using a scanning signal

Landscapes

  • Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)

Abstract

1339603 APC systems STANDARD TELEPHONES & CABLES Ltd 8 March 1971 6240/71 Heading H3A A variable frequency generator comprises a phase controlled loop including a voltage controlled oscillator 1, first and second mixers 4, 7, an arrangement including a low pass filter 12 and a frequency acquisition circuit 10 producing a control voltage for effecting initial frequency sweep of oscillator 1 and to effect phase synchronization, sources 5, 8 producing frequencies fb,fc and a further arrangement including a third mixer 11 and a phase shifter 13 for unambiguously choosing the output frequency fa to be one of two values fb+fc or fb-fc. The mixers 7, 11 are of the phase detecting type and a phase shifter 13 connected in series with the appropriate one of the mixers 7, 11 ensures that the output frequency fa has the desired value. The filter 9 includes a capacitor which is charged and discharged by the change over in states of a flip-flop included in circuit 10 for initiating the frequency sweep of oscillator 1.
GB624071*[A 1971-03-08 1971-03-08 Phase locked loops Expired GB1339603A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB624071 1971-03-08

Publications (1)

Publication Number Publication Date
GB1339603A true GB1339603A (en) 1973-12-05

Family

ID=9810957

Family Applications (1)

Application Number Title Priority Date Filing Date
GB624071*[A Expired GB1339603A (en) 1971-03-08 1971-03-08 Phase locked loops

Country Status (1)

Country Link
GB (1) GB1339603A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2155711A (en) * 1984-03-13 1985-09-25 Alcatel Thomson Faisceaux Ultrahigh frequency active filter

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2155711A (en) * 1984-03-13 1985-09-25 Alcatel Thomson Faisceaux Ultrahigh frequency active filter

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Legal Events

Date Code Title Description
PS Patent sealed [section 19, patents act 1949]
PCNP Patent ceased through non-payment of renewal fee