GB782878A - Improvements in or relating to automatically controlled variable frequency oscillators - Google Patents
Improvements in or relating to automatically controlled variable frequency oscillatorsInfo
- Publication number
- GB782878A GB782878A GB29057/55A GB2905755A GB782878A GB 782878 A GB782878 A GB 782878A GB 29057/55 A GB29057/55 A GB 29057/55A GB 2905755 A GB2905755 A GB 2905755A GB 782878 A GB782878 A GB 782878A
- Authority
- GB
- United Kingdom
- Prior art keywords
- frequency
- output
- discriminator
- oscillator
- sweep
- 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
Links
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03C—MODULATION
- H03C3/00—Angle modulation
- H03C3/02—Details
- H03C3/09—Modifications of modulator for regulating the mean frequency
Landscapes
- Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
- Apparatuses For Generation Of Mechanical Vibrations (AREA)
Abstract
782,878. Automatic frequency-control systems. SOC. FRANCAISE RADIO-ELECTRIQUE. Oct. 12, 1955 [Nov. 12, 1954], No. 29057/55. Class 38 (4). A frequency sweep oscillator 1 has its frequency sweep stabilized by a control loop, including a frequency discriminator 3 whose output is additively combined with the sweep voltage in a comparator circuit 4 as negative feed-back. Also, during intervals when the frequency sweep is inoperative, the discriminator output is corrected for each of two different voltages alternately applied at the control voltage input 15 so that the discriminator zero output and characteristic slop are both corrected as necessary. The oscillator output may first be transposed down in frequency by a stable heterodyne oscillator 7 and applied to each of two circuits having frequency discriminators 11, 20 tuned to centre frequencies fn, fm alternately with reference frequencies of these values fn, fm, from stable oscillators 10, 19, the change-over for each circuit being controlled by an electronic or other switch 26 at a frequency, e.g. 50 c/s. The outputs of discriminators 11, 20 will thus be rectangular pulses of amplitude and polarity depending on drift of the transposed frequency from the values fn, fm. The pulses are applied through gated amplifiers 12, 21 opened alternately by a gating control circuit 27 only during constant reference voltages Un, Um being applied at 15 (while the frequency sweep of oscillator 1 is inoperative), to one phase of two phase motors 13, 22 whose other phase inputs are the switching frequencies (50 c/s) of switch 26. The motor 13 opertaes a potentiometer slider 24 to vary a bias additively combined with the output of discriminator 3 to correct this output to the required value producing frequency fn at the output 16. Moreover, motor 22 drives the tapping point of the output potentiometer 28 fed by discriminator 3 so that the characteristic slope is controlled to give an output of correct value also at the frequency fm.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR782878X | 1954-11-12 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB782878A true GB782878A (en) | 1957-09-11 |
Family
ID=9213508
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB29057/55A Expired GB782878A (en) | 1954-11-12 | 1955-10-12 | Improvements in or relating to automatically controlled variable frequency oscillators |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB782878A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3136956A (en) * | 1961-09-29 | 1964-06-09 | Bell Telephone Labor Inc | Oscillator frequency control by phase null detection |
FR2616285A1 (en) * | 1987-06-05 | 1988-12-09 | Thomson Semiconducteurs | DEVICE FOR THE MINIMAL AND MAXIMUM FREQUENCY ADJUSTMENT OF A FREQUENCY MODULE VIDEO SIGNAL |
-
1955
- 1955-10-12 GB GB29057/55A patent/GB782878A/en not_active Expired
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3136956A (en) * | 1961-09-29 | 1964-06-09 | Bell Telephone Labor Inc | Oscillator frequency control by phase null detection |
FR2616285A1 (en) * | 1987-06-05 | 1988-12-09 | Thomson Semiconducteurs | DEVICE FOR THE MINIMAL AND MAXIMUM FREQUENCY ADJUSTMENT OF A FREQUENCY MODULE VIDEO SIGNAL |
EP0296989A1 (en) * | 1987-06-05 | 1988-12-28 | STMicroelectronics S.A. | Device for adjusting the minimal and maximal frequencies of a frequency modulated video signal |
US4918529A (en) * | 1987-06-05 | 1990-04-17 | Sgs-Thomson Microelectronics S.A. | Device for setting minimal and maximal frequencies of a frequency modulated video signal |
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