GB642560A - Frequency modulation of electric oscillation generators - Google Patents
Frequency modulation of electric oscillation generatorsInfo
- Publication number
- GB642560A GB642560A GB9307/48A GB930748A GB642560A GB 642560 A GB642560 A GB 642560A GB 9307/48 A GB9307/48 A GB 9307/48A GB 930748 A GB930748 A GB 930748A GB 642560 A GB642560 A GB 642560A
- Authority
- GB
- United Kingdom
- Prior art keywords
- crystal
- grid
- capacity
- frequency
- tube
- 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
- H03C3/10—Angle modulation by means of variable impedance
- H03C3/12—Angle modulation by means of variable impedance by means of a variable reactive element
- H03C3/14—Angle modulation by means of variable impedance by means of a variable reactive element simulated by circuit comprising active element with at least three electrodes, e.g. reactance-tube circuit
Landscapes
- Oscillators With Electromechanical Resonators (AREA)
Abstract
642,560. Frequency modulation. STAN DARD TELEPHONES & CABLES, Ltd. April 2, 1948, No. 9307. Convention date, May 24, 1947. [Class 40 (v)] A crystal-controlled oscillator is modulated in frequency by applying the signal voltage to the grid of a modulator tube to vary its gridcathode capacity, which is connected across the crystal of the oscillator; and means are provided to neutralize the shunt capacity of the crystal and its holder in order to increase the frequency deviation obtainable. In Fig. 1 the oscillator tube 10 has the crystal 16 connected in its grid circuit, and the pentode modulator tube 18 has its grid-cathode circuit connected across the crystal. The grid-cathode capacity, and the frequency of the oscillations generated, are varied by applying the signal voltage from a source 19 to the grid of the tube 18, which has its anode circuit tuned to the crystal frequency. The shunt capacity across the crystal 16 is neutralized by a corresponding inductance coil 20. The modulating signals may be distorted by a network 33 favouring the higher signal frequencies, in order to obtain linear modulation. In Fig. 3, the tuned anode circuit of the modulator tube 18 is centretapped and a voltage of opposite phase to the anode voltage is fed to the grid through a condenser 34. The grid.cathode impedance of the valve 18 is then a negative capacity which is variable by the modulating signal 19, and at its mean value neutralizes the positive shunting capacity of the crystal 16.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US642560XA | 1947-05-24 | 1947-05-24 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB642560A true GB642560A (en) | 1950-09-06 |
Family
ID=22054643
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9307/48A Expired GB642560A (en) | 1947-05-24 | 1948-04-02 | Frequency modulation of electric oscillation generators |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB642560A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2741700A (en) * | 1953-01-29 | 1956-04-10 | Hall James William | Piezo-electric crystal controlled frequency selective apparatus |
-
1948
- 1948-04-02 GB GB9307/48A patent/GB642560A/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2741700A (en) * | 1953-01-29 | 1956-04-10 | Hall James William | Piezo-electric crystal controlled frequency selective apparatus |
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