GB290642A - Improvements in radio telephone signalling - Google Patents
Improvements in radio telephone signallingInfo
- Publication number
- GB290642A GB290642A GB14590/28A GB1459028A GB290642A GB 290642 A GB290642 A GB 290642A GB 14590/28 A GB14590/28 A GB 14590/28A GB 1459028 A GB1459028 A GB 1459028A GB 290642 A GB290642 A GB 290642A
- Authority
- GB
- United Kingdom
- Prior art keywords
- variations
- frequency
- amplifier
- amplitude
- valve
- 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
- H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
- H03D3/00—Demodulation of angle-, frequency- or phase- modulated oscillations
- H03D3/02—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal
- H03D3/06—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal by combining signals additively or in product demodulators
- H03D3/12—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal by combining signals additively or in product demodulators by means of discharge tubes having more than two electrodes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
- B03C3/34—Constructional details or accessories or operation thereof
- B03C3/74—Cleaning the electrodes
- B03C3/78—Cleaning the electrodes by washing
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Noise Elimination (AREA)
Abstract
290,642. Armstrong, E. H. May 18, 1937, [Convention date]. Transmitting and receiving systems; thermionic modulating systems ; fading, preventing. -In order to eliminate fading and reduce the effect of static interference, signalling is effected by varying the frequency but not the amplitude of the carrier wave. In reception, different impedance branches are used to convert the frequency variations back into corresponding voltage variations, whilst limiting devices are interposed at the transmitting and receiving ends for maintaining the amplitude constant. In transmitting, Fig. 1, the frequency of the tuned oscillator circuit 1, 3 is varied at speechfrequency by the changing reactance of the closely-coupled valve circuit 6, 7 under the influence of the microphone 10. The resulting oscillations are fed through a coupling-coil 12 to an amplifier 13, and then pass through a limiting valve 16 of the screened-grid type in which any existing amplitude-variations are smoothed out. Before the outgoing signals reach the aerial 25 they are passed through a band filter 20 and power amplifier 23. At the receiving end, Fig. 2, the incoming signals are passed through band filters 32, 35, amplifier 33, and a currentlimiter 34 to eliminate amplitude variations. They are then applied to an input circuit 39, 40, 41, which is so adjusted that the portion BC, across the amplifier 42, is non-reactive for the lowest frequency of the signal band, whilst the portion AC across the amplifier 43 is non- reactive for the highest received frequency. The circuit as a whole is made substantially aperiodic by adjusting the resistance 37, so as to balance out any residual amplitude-variations. In these circumstances the output from the detectors 48, 49 will vary in a straight-line law with the input frequency-variations, but will be indifferent to amplitude variations and will therefore reproduce the original signal in the phones 54. At the same time the effect of static interference is reduced. Instead of the arrangement shown in Fig. 1, frequency modulation may be effected by coupling a push-pull valve amplifier across capacitative and inductive reactions arranged on the input circuit of the oscillator valve. In order to reduce damping in the receiver circuits, a valve 63, Fig. 4, may be applied across a resistance 62 in the input branches A B C so as to introduce a negativeresistance effect through a tapping from the plate resistance 64.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US290642XA | 1927-05-18 | 1927-05-18 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB290642A true GB290642A (en) | 1929-07-18 |
Family
ID=21847022
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB14590/28A Expired GB290642A (en) | 1927-05-18 | 1928-05-18 | Improvements in radio telephone signalling |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB290642A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE924809C (en) * | 1933-01-24 | 1955-03-07 | Esther Marion Armstrong | Method for reducing spectrum-like interference during wireless transmission of the listening frequency band by means of frequency-modulated high-frequency oscillations |
-
1928
- 1928-05-18 GB GB14590/28A patent/GB290642A/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE924809C (en) * | 1933-01-24 | 1955-03-07 | Esther Marion Armstrong | Method for reducing spectrum-like interference during wireless transmission of the listening frequency band by means of frequency-modulated high-frequency oscillations |
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