GB628253A - Improvements relating to apparatus for controlling the frequency of an oscillator - Google Patents
Improvements relating to apparatus for controlling the frequency of an oscillatorInfo
- Publication number
- GB628253A GB628253A GB5931/46A GB593146A GB628253A GB 628253 A GB628253 A GB 628253A GB 5931/46 A GB5931/46 A GB 5931/46A GB 593146 A GB593146 A GB 593146A GB 628253 A GB628253 A GB 628253A
- Authority
- GB
- United Kingdom
- Prior art keywords
- pulses
- saw
- tooth
- tube
- synchronizing
- 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
- 230000000903 blocking effect Effects 0.000 abstract 2
- 239000002131 composite material Substances 0.000 abstract 2
- 230000008878 coupling Effects 0.000 abstract 2
- 238000010168 coupling process Methods 0.000 abstract 2
- 238000005859 coupling reaction Methods 0.000 abstract 2
- 230000001419 dependent effect Effects 0.000 abstract 1
- 230000000694 effects Effects 0.000 abstract 1
- 238000004804 winding Methods 0.000 abstract 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/04—Synchronising
- H04N5/12—Devices in which the synchronising signals are only operative if a phase difference occurs between synchronising and synchronised scanning devices, e.g. flywheel synchronising
- H04N5/126—Devices in which the synchronising signals are only operative if a phase difference occurs between synchronising and synchronised scanning devices, e.g. flywheel synchronising whereby the synchronisation signal indirectly commands a frequency generator
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
- Details Of Television Scanning (AREA)
Abstract
628,253. Automatic frequency-control systems. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Feb. 26, 1946, No. 5931. Convention date, July 29, 1944. [Class 38 (iv)] Apparatus for controlling the frequency of an oscillator or oscillators, as in the deflection circuits of television receivers, comprises means for generating a pair of saw-tooth waves having a definite time relation with respect to the frequency of the oscillator and having sloping portions which slope simultaneously in the same direction, a phase-inverting tube to which synchronizing pulses are fed to produce pulses of opposite polarity which are applied simultaneously to the saw-tooth voltages to produce a pair of resultant pulses such that a change in the phase relation of one saw-tooth wave and its superimposed synchronizing pulse causes the peak amplitude of the resultant pulse to increase, whilst a similar change in phase of the other saw-tooth and its superimposed synchronizing pulse effects a decrease in the peak amplitude of the resultant pulse, means for producing a control voltage having a value which changes in response to a change in the relative peak amplitudes of the resultant pulses, and means for controlling the frequency of the oscillator in accordance with the control voltage. In an example the input circuit comprise;' video amplifier 53 with anode connected to a peaking circuit 55 of known arrangement, and to an output point 58 to the control grid of a cathode-ray tube. A duplex type tube 59 functions as a D.C. restorer and synchronizing separator and amplifier, and feeds a synchronizing pulse through a differentiating circuit including a coupling condenser 134 to the grid of a phase-inverter tube 133 in the line timebase circuit, while the grid of a phase-inverter tube 141 in the frame time-base circuit is fed through a condenser 143 and a resistor 144 associated with a condenser 146 in an integrating circuit. Pulses appearing on the control grid 138 of tube 133 are applied in opposite phase by way of an anode connected condenser 124 and cathode connected condenser 126 to a phase detector comprising a duplex diode 159, or a pair of diodes. Coupling resistances 161 and 162 of the tube 133 are such that positive pulses provided on the plate and negative pulses on the cathode are substantially of equal amplitude. These synchronizing pulses . of opposite polarity are superimposed on a pair of saw-tooth waves derived from pulses fed over feed-back line 119 from an output tube 89 which has its anode connected to the primary winding of a transformer 86, the control grid of tube 89 being connected to a horizontal sawtooth generator circuit comprising a blocking oscillator portion of a double triode 88, and a saw-tooth generator portion with an anode 108 connected to a condenser 109. The frequencycontrol of the system is dependent on the degree of bias applied to the grid 183 of the blocking oscillator from a point 171 and over an amplifier 182. The pulses fed over the line 119 from tube 89 are received by a filter comprising a resistor 121 and condenser 122, thereby producing sawtooth waves which are applied to the anode 169 of one portion, and cathode 164 of the other portion of the duplex diode 159, these saw-tooth waves being in phase, and upon these waves are superimposed the synchronizing pulses, the synchronizing pulse applied to anode 169 being in the positive sense while that applied to cathode 164 is in the negative sense. The time relation is such that the synchronizing pulses are positioned on the return or re-trace portion of the saw-tooth, and any change in the phaserelation of the saw-tooth wave and synchronizing pulses causes an increase in the peak amplitude of one composite signal and a decrease in the peak amplitude of the other composite signal. The duplex diode 159 functions as a peak rectifier, and in the signal appearing at the point 171 the synchronizing pulses are effectively balanced out, leaving only the saw-tooth component, which is filtered out by a circuit comprising a resistor 130 and condensers 131, 132, leaving a D.C. control potential which is applied to the grid of amplifier 182. Specifications 562,513 and 589,327, [Group XL], are referred to.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US547230A US2458156A (en) | 1944-07-29 | 1944-07-29 | Automatic frequency control system |
Publications (1)
Publication Number | Publication Date |
---|---|
GB628253A true GB628253A (en) | 1949-08-25 |
Family
ID=24183848
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB5931/46A Expired GB628253A (en) | 1944-07-29 | 1946-02-26 | Improvements relating to apparatus for controlling the frequency of an oscillator |
Country Status (2)
Country | Link |
---|---|
US (1) | US2458156A (en) |
GB (1) | GB628253A (en) |
Families Citing this family (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2574946A (en) * | 1946-12-19 | 1951-11-13 | Emi Ltd | Scanning circuit |
US2543066A (en) * | 1947-02-01 | 1951-02-27 | Farnsworth Res Corp | Automatic picture phasing circuit |
US2633538A (en) * | 1947-10-31 | 1953-03-31 | Rca Corp | Beam deflection control |
US2610298A (en) * | 1947-12-26 | 1952-09-09 | Gen Electric | Stabilized saw tooth oscillator |
US2670438A (en) * | 1948-07-10 | 1954-02-23 | Motorola Inc | Automatic frequency control circuit |
US2559173A (en) * | 1948-08-26 | 1951-07-03 | Sun Oil Co | Selective circuits |
US2717959A (en) * | 1950-02-28 | 1955-09-13 | Du Mont Allen B Lab Inc | Automatic frequency control circuit |
US2594380A (en) * | 1950-04-01 | 1952-04-29 | Rca Corp | Synchronizing apparatus for color signal sampling oscillators |
US2632050A (en) * | 1950-04-03 | 1953-03-17 | Avco Mfg Corp | Keyed automatic frequency control system for television receivers |
US2866893A (en) * | 1950-09-18 | 1958-12-30 | Martin Co | Pulse time comparator |
US2672510A (en) * | 1950-09-28 | 1954-03-16 | Stromberg Carlson Co | Vertical synchronization circuit for television receivers |
US2772358A (en) * | 1951-02-16 | 1956-11-27 | Emi Ltd | Scanning circuits for cathode ray tubes |
US2869026A (en) * | 1952-01-02 | 1959-01-13 | Du Mont Allen B Lab Inc | Cathode ray sweep correction system |
US3030436A (en) * | 1952-01-05 | 1962-04-17 | Rca Corp | Color synchronizing apparatus |
US2779817A (en) * | 1952-11-25 | 1957-01-29 | Color Television Inc | Color television camera stabilizing circuit |
US2925466A (en) * | 1956-03-29 | 1960-02-16 | Sylvania Electric Prod | Television receiver |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2361255A (en) * | 1923-12-29 | 1944-10-24 | Westinghouse Electric & Mfg Co | Facsimile-transmission system |
US2132654A (en) * | 1934-10-18 | 1938-10-11 | Rca Corp | Electrical apparatus |
USRE22055E (en) * | 1936-07-08 | 1942-03-24 | Synchronization system fob | |
US2201978A (en) * | 1938-10-26 | 1940-05-28 | Rca Corp | Frequency control circuits |
US2250284A (en) * | 1938-10-26 | 1941-07-22 | Rca Corp | Frequency control circuits |
US2209507A (en) * | 1939-02-15 | 1940-07-30 | Du Mont Allen B Lab Inc | Synchronizing generator |
US2275460A (en) * | 1939-11-01 | 1942-03-10 | Robert M Page | Electron beam control apparatus |
US2339536A (en) * | 1941-06-28 | 1944-01-18 | Rca Corp | Television system |
US2358545A (en) * | 1941-07-31 | 1944-09-19 | Rca Corp | Television system |
-
1944
- 1944-07-29 US US547230A patent/US2458156A/en not_active Expired - Lifetime
-
1946
- 1946-02-26 GB GB5931/46A patent/GB628253A/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
US2458156A (en) | 1949-01-04 |
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