GB675439A - Improvements in or relating to phase modulators for electric carrier waves - Google Patents
Improvements in or relating to phase modulators for electric carrier wavesInfo
- Publication number
- GB675439A GB675439A GB1745550A GB1745550A GB675439A GB 675439 A GB675439 A GB 675439A GB 1745550 A GB1745550 A GB 1745550A GB 1745550 A GB1745550 A GB 1745550A GB 675439 A GB675439 A GB 675439A
- Authority
- GB
- United Kingdom
- Prior art keywords
- valves
- valve
- phase
- signal
- output
- 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
- H03C3/08—Modifications of modulator to linearise modulation, e.g. by feedback, and clearly applicable to more than one type of modulator
Landscapes
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
Abstract
675,439. Phase modulation. STANDARD TELEPHONES & CABLES, Ltd. July 12, 1950, No. 17455/50. Class 40 (v). A phase modulator, of the kind in which phase-shifted versions of the carrier wave are amplitude-modulated in opposed senses by the signal and then re-combined, employs a pair of principal modulator valves 1, 2 and a pair of auxiliary modulator valves 22, 23 with the object of securing linear relation between carrier phase-shift and signal voltage. The carrier is applied at terminal 6 to the grids of both pairs of valves, the lead to valve 1 including a phaseretarding coil 7 and the lead to valve 2 a phaseadvancing condenser 8. The leads to valves 22, 23 include coupling capacities 28, 29 large enough to avoid substantial phase shift. The modulating signal is applied through a transformer 15 in push-pull to the grids of both valve pairs. The valves 1, 2 are so biased that they operate as linear amplitude modulators and their combined anode output is fed to one section of a tapped primary coil 3, the secondary of which is connected to output terminals 16, 17. The other section of the coil 3 is connected to the anodes of both auxiliary valves 22, 23, the grids of which are biased to near cut-off so that the valves are non-effective except when substantial positive signal voltages are applied from the transformer 15. Thus for signal peaks of one polarity, the phase-shifted wave at the output terminals 16, 17 resulting from the combined output from the valves 1, 2 is given a supplementary phase shift by the output from valve 22, and the valve 23 is ineffective. For peaks of the other polarity, the supplementary phase shift is provided by the valve 23. Bias adjustments by the cathode resistors 20, 21, 25, 27 enable modulation distortion to be substantially eliminated. The triode valves shown are preferably replaced by pentodes.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1745550A GB675439A (en) | 1950-07-12 | 1950-07-12 | Improvements in or relating to phase modulators for electric carrier waves |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1745550A GB675439A (en) | 1950-07-12 | 1950-07-12 | Improvements in or relating to phase modulators for electric carrier waves |
Publications (1)
Publication Number | Publication Date |
---|---|
GB675439A true GB675439A (en) | 1952-07-09 |
Family
ID=10095475
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1745550A Expired GB675439A (en) | 1950-07-12 | 1950-07-12 | Improvements in or relating to phase modulators for electric carrier waves |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB675439A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3118117A (en) * | 1959-10-30 | 1964-01-14 | Int Standard Electric Corp | Modulators for carrier communication systems |
-
1950
- 1950-07-12 GB GB1745550A patent/GB675439A/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3118117A (en) * | 1959-10-30 | 1964-01-14 | Int Standard Electric Corp | Modulators for carrier communication systems |
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