GB564045A - Improvements in and relating to frequency modulation apparatus - Google Patents
Improvements in and relating to frequency modulation apparatusInfo
- Publication number
- GB564045A GB564045A GB8573/43A GB857343A GB564045A GB 564045 A GB564045 A GB 564045A GB 8573/43 A GB8573/43 A GB 8573/43A GB 857343 A GB857343 A GB 857343A GB 564045 A GB564045 A GB 564045A
- Authority
- GB
- United Kingdom
- Prior art keywords
- phase
- valve
- carrier
- resistance
- modulation
- 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
- H03C3/38—Angle modulation by converting amplitude modulation to angle modulation
- H03C3/40—Angle modulation by converting amplitude modulation to angle modulation using two signal paths the outputs of which have a predetermined phase difference and at least one output being amplitude-modulated
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03C—MODULATION
- H03C3/00—Angle modulation
- H03C3/02—Details
- H03C3/06—Means for changing frequency deviation
-
- 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
- Amplifiers (AREA)
- Amplitude Modulation (AREA)
- Control Of Ac Motors In General (AREA)
Abstract
564,045. Phase and frequency modulation. BRITISH THOMSON-HOUSTON CO., Ltd. May 28, 1943, No. 8573. Convention date, May 28, 1942. [Class 40 (v)] Relates to phase modulation systems in which two or more phase-displaced carrier voltages are amplitude modulated and combined vectorially to produce the phase-modulated wave ; and comprises means for obtaining a linear relation between signal voltage and phase deviation by deriving a voltage proportional to the amplitude modulation of the combined wave and applying it as an additional or correcting phase modulation voltage. As shown, the carrier from a source 10 is applied in phase opposition to the inner grids of the valves 11, 13 and in quadrature to the inner grid of the valve 12. The signal from a microphone 16 is applied in phase opposition to the screen grids of valves 11, 13, but the valve 12 is unmodulated,. The anodes of the three valves are connected to each other and to a tuned output circuit 43, 44 feeding a phase-modulated wave to the aerial 15 through an amplifier 14. Amplitude modulation also present in the carrier is rectified by the diode 71, the load resistance 72 being connected in the grid circuit of an amplifier 81, the anode resistance 50 of which is in the screen lead of the valve 12. A vapour discharge device 82 is connected between the cathode of valve 81 and earth. In this way, as the depth of modulation rises, the screen of valve 12 becomes less positive and the strength of its unmodulated carrier output is reduced. This applies a correction of phase angle to the carrier in the circuit 43, 44, and by adjustment of the resistance 50 a linear relation is obtained between the phase deviation and the modulating signal. The valve 81 may be omitted if the diode 71 is inverted and a portion of its load resistance 72 is included in the screen circuit of the valve 12, Fig. 9 (not shown). A condenser-resistance coupling may replace the direct connection to the.grid of the valve 81, and a resistance may be used in-place of the discharge device 82, Fig. 10 (not shown). A low-pass filter may be inserted between the rectifier 71 and the valve 81 for reducing the effect of the higher frequency components of the modulating signal, Fig. 8 (not shown). The system permits a large phase shift of the carrier wave and reduces the amount of frequency multiplication necessary to produce a suitable frequency deviation. Specification 562,432 is referred to.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US440172A US2347458A (en) | 1942-04-23 | 1942-04-23 | Frequency modulation system |
US444843A US2347459A (en) | 1942-04-23 | 1942-05-28 | Frequency modulation apparatus |
Publications (1)
Publication Number | Publication Date |
---|---|
GB564045A true GB564045A (en) | 1944-09-11 |
Family
ID=27032333
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB6244/43A Expired GB562432A (en) | 1942-04-23 | 1943-04-19 | Improvements in and relating to frequency modulation system |
GB8573/43A Expired GB564045A (en) | 1942-04-23 | 1943-05-28 | Improvements in and relating to frequency modulation apparatus |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB6244/43A Expired GB562432A (en) | 1942-04-23 | 1943-04-19 | Improvements in and relating to frequency modulation system |
Country Status (4)
Country | Link |
---|---|
US (1) | US2347459A (en) |
BE (2) | BE477900A (en) |
FR (2) | FR926719A (en) |
GB (2) | GB562432A (en) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2551348A (en) * | 1945-03-28 | 1951-05-01 | Philco Corp | Electrical apparatus |
US2460965A (en) * | 1945-09-10 | 1949-02-08 | Zenith Radio Corp | Phase modulation system |
US2645710A (en) * | 1948-03-12 | 1953-07-14 | Hartz Julius | Radio transmission and carrier wave modulation |
US2590784A (en) * | 1948-11-26 | 1952-03-25 | Philco Corp | Heterodyne frequency modulator with automatic deviation control |
US2659813A (en) * | 1950-02-11 | 1953-11-17 | Bell Telephone Labor Inc | Frequency modulation repeater |
-
0
- BE BE466324D patent/BE466324A/xx unknown
- BE BE477900D patent/BE477900A/xx unknown
-
1942
- 1942-05-28 US US444843A patent/US2347459A/en not_active Expired - Lifetime
-
1943
- 1943-04-19 GB GB6244/43A patent/GB562432A/en not_active Expired
- 1943-05-28 GB GB8573/43A patent/GB564045A/en not_active Expired
-
1946
- 1946-05-09 FR FR926719D patent/FR926719A/en not_active Expired
- 1946-10-15 FR FR55048D patent/FR55048E/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
FR55048E (en) | 1951-06-05 |
US2347459A (en) | 1944-04-25 |
GB562432A (en) | 1944-06-30 |
FR926719A (en) | 1947-10-09 |
BE466324A (en) | |
BE477900A (en) |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US2282714A (en) | Method and means for the linear transmission or amplification of amplitude-modulatedcarrier waves | |
Price | The circuit development of the ampliphase broadcasting transmitter | |
US2294800A (en) | Modulation system | |
US2682640A (en) | Arrangement for modulating electric carrier wave oscillations | |
GB564045A (en) | Improvements in and relating to frequency modulation apparatus | |
GB1022542A (en) | Improvements relating to frequency modulators | |
GB627693A (en) | Improvements in valve modulators | |
US2539952A (en) | Frequency modulation | |
GB534723A (en) | Improvements in or relating to receivers for frequency or phase modulated oscillations | |
US2027044A (en) | Modulating means | |
US2315050A (en) | Frequency modulation system | |
GB947306A (en) | Improvements in and relating to signal modulating apparatus | |
US2784909A (en) | Electronic multiplier | |
US2120800A (en) | Transmitter | |
Villard | A high-level single-sideband transmitter | |
US2130172A (en) | Radio transmitting system | |
US2163719A (en) | Modulation | |
US2439661A (en) | System for true amplitude modulation of radio waves | |
GB515106A (en) | Improvements in or relating to modulator carrier wave transmitters | |
GB413647A (en) | Improvements in or relating to carrier wave transmission systems | |
GB641543A (en) | Improvements in or relating to frequency-modulation circuits | |
US2588302A (en) | Method of and device for transforming amplitude modulation into phase modulation | |
US2161851A (en) | Carrier wave modulator arrangement | |
US2238255A (en) | Modulated carrier wave transmitter | |
GB546132A (en) | Improvements relating to the generation of frequency modulated electrical oscillations |