US2248975A - Electrical oscillation generator - Google Patents
Electrical oscillation generator Download PDFInfo
- Publication number
- US2248975A US2248975A US255795A US25579539A US2248975A US 2248975 A US2248975 A US 2248975A US 255795 A US255795 A US 255795A US 25579539 A US25579539 A US 25579539A US 2248975 A US2248975 A US 2248975A
- Authority
- US
- United States
- Prior art keywords
- valve
- grid
- anode
- condenser
- cathode
- 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 - Lifetime
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Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K4/00—Generating pulses having essentially a finite slope or stepped portions
- H03K4/06—Generating pulses having essentially a finite slope or stepped portions having triangular shape
- H03K4/08—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape
- H03K4/10—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements vacuum tubes only
- H03K4/26—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements vacuum tubes only in which a sawtooth current is produced through an inductor
- H03K4/39—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements vacuum tubes only in which a sawtooth current is produced through an inductor using a tube operating as an amplifier
- H03K4/43—Generating pulses having essentially a finite slope or stepped portions having triangular shape having sawtooth shape using as active elements vacuum tubes only in which a sawtooth current is produced through an inductor using a tube operating as an amplifier combined with means for generating the driving pulses
Definitions
- This invention relates to electrical oscillation generators and more particularly to electrical oscillation generators for generating saw-tooth or substantially saw-tooth electrical waves suitable for scanning deflections in television and like apparatus.
- relaxation oscillation generator say, for example, a blocking oscillator, as employed for the production of saw-tooth electrical waves the output is usually insufficient to deflect the scanning beam, for instance, of a cathode ray tube, to the required degree and it has been the normal practice to connect.
- a thermionic amplifier or output stage after the oscilla tion generator in order to increase the output has been proposed to apply negative feedback to such an output stage both to straighten the amplifying characteristic and to linearize the charging curve of the condenser of the relaxation oscillation generator.
- a saw-tooth oscilvalve for supplying a substantially saw-tooth electrical waveform to.an output circuit, said output valve being provided with negative feedback for improving said waveform, the output circuit of said output valve being coupled back to the grid-cathode circuit of the thermionic valve used for discharging said condenser for the purpose of producing blocking oscillations.
- the anodes of the two triode thermionic valves illand 5 are joined by a charging condenser 3, and the anode of valve It is connected to a source of positivepotential through the charging resistance i, the. anode of valve 5 being connected to the same source by means of an output transformer 6 to which the deflecting coil ll of a cathode ray tube is connected.
- the cathode of valve is connected to the negative side of the potential source, to which is connected the grid of the valve it by means of grid resistance 2.
- the grid of valve It is connected to the anode of valve 5 via condenser l and the anode of valve it is connected to the grid of valve 5 via condenser 8.
- the resistance i3 and condenser i l form the self-biasing circuit for the cathode of valve 5, the resistance 9 being the grid resistance.
- condenser I should be appreciably smaller than condenser 3.
- the short flank of the saw-tooth wave may be further improved if desired, by inserting a suitable resistance in series with condenser 3 or a low-pass filter may be associated with the feedback path for the same purpose.
- the frequency of the saw-tooth oscillations is controlled by varying the resistance [2, and the amplitude of the oscillations is controlled either by varying the resistance 4 or, preferably, by varying the potential applied to the resistance. It is found that variation of amplitude tends to vary the frequency, for example, as the amplitude is increased, the frequency is lowered. This effect may be largely overcome by returning the grid leak resistance l2 to the anode of valve H1 or to a tapping on resistance 4, instead of to the cathode of valve 10. By this means an increase in amplitude will also cause an increase in the positive potential on the grid leak I2 and thereby shortening the time of recovery to the critical grid potential. When using this method the time constant of the condenser l and resistance l2 can be increased.
- synchronising signals may be applied in a positive sense to the grid of valve II] or to the anode of valve 5.
- synchronising signals in the negative sense may be applied to the grid of valve 5 or to the anode of valve In. In the latter case the synchronising pulse will be amplified by valve 5 before being fed to the grid of valve l0.
- a cathode follower type of circuit is one in which .negative feedback is obtained by the provision of an impedance in the cathode lead of a valve, which impedance is large compared with the inverse of the mutual conductance of the valve, so that the potential of the cathode follows substantially potential variations of the grid of the valve.
- the main point of difference between the cathode follower and other negative feedback circuits lies in the fact that the former will reproduce the input wave form almost exactly provided that the load circuit is effectively resistive.
- the output load comprises a transformer nonlinearity due to low primary inductance is successfully compensated.
- Another useful feature is that where the load is partly inductive, as during the short flank period, a larger negative bias than usual can be applied to the valve thus economising in anode current.
- the primary winding of the transformer is wound with a suitable D. C. resistance for automatically biasing the valve.
- the circuit of Figure 2 combines a discharging valve In with a cathode follower valve to form an oscillating circuit. In operation it is'similar to the circuit of Figure 1, except that a non-linear input waveform of the valve 5 is not linearised.
- the blocking condenser I is connected between the cathodes of the two valves Ill and 5 and the resistance I2 is used to produce the cathode bias of valve Ill.
- the output to the deflecting coil H is taken from transformer 6 in the cathode circuit of valve 5, the anode of which is taken directly to the positive potential source.
- the grid of valve I0 is connected directly to the negative potential source.
- the frequency of oscillation is controlled by the time constant of resistance l2 and condenser 7.
- a resistance and condenser l5 may be connected between the grid of tube l0 and the resistance [2 for controlling the frequency of oscillation.
- synchronising signals can be applied in a negative sense to the grid of valve 5 or to the anode of valve l0.
- the synchronising signals may be applied in a positive sense to the grid of valve l 0.
- the combined picture and synchronising potentials may be applied to the grid without separation if the D. 0. component of the signals is present, and a low pass filter is used to cut off frequencies higher than the frame frequency, assuming that the oscillation generator is being used for frame scanning.
- the circuit of Figure 2 may be modified by the inclusion of an impedance in the anode circuit of valve 5 and by connecting the condenser 3 between the anode of valve I0 and the anode of valve 5 thus forming a negative feedback circuit which has the effect of linearising the charging curve of condenser 3.
- This anode impedance may consist of an additional winding on the transformer 6. It will be apparent in the circuit of Figure 1 that transformer 6 may have an additional winding connected in the cathode circuit of valve 5 in place of resistance I3 and condenser I4 for the purpose of additional negative feedback.
- circuits described are particularly useful for the production of frame scanning oscillations in a television recciver or in other circuits where the resistive component of the output circuit, as, for example, the scanning coils, is greater than the reactive component, at least during the long flank of the saw-tooth waveform.
- a sawtooth oscillation generator comprising a first thermionic tube having a cathode, grid and anode, a variable resistor connected between said cathode and grid, a second thermionic tube having a cathode, grid, anode and an electron path between the cathode and anode of said second thermionic tube, at least one source of direct current supply voltage, a serially connected resistor and condenser, said serially connected resistor being connected to the positive terminal of said source, a connection from the junction point of said serially connected resistor and said condenser to the anode of said first thermionic tube, a capacity coupling from said junction to the grid of said second thermionic tube, a resistor connected between the grid of said second thermionic tube and the negative terminal of said source, an impedance connected in series with said source and said electron path, a direct connection between said condenser and said impedance, means to supply output energy from said impedance, and capacit
- a sawtooth oscillation generator comprising a first thermionic tube having a cathode, grid and anode, a variable resistor connected between said cathode and grid, a second thermionic tube having a cathode, grid, anode and an electron path between the cathode and anode of said second thermionic tube, at least one source of direct current supply voltage, a serially connected resistor and condenser, said serially connected resistor being connected to the positive terminal of said source, a connection from the junction point of said serially connected resistor and said condenser to the anode of said first thermionic tube, a capacity coupling from said junction to the grid of said second thermionic tube, a resistor connected between the grid of said second thermionic tube and the negative terminal of said source, a transformer having a primary and secondary winding with said primary winding connected in series with said source and said electron path, a direct connection between said condenser and said primary winding, a, de
- a sawtooth oscillation generator comprising a first thermionic tube having a cathode, grid and anode, a variable resistor connected between said cathode and grid, a second thermionic tube having a cathode, grid, anode and an electron path between the cathode and anode of said second thermionic tube, a source of direct current supply voltage, a serially connected resistor and condenser, said serially connected resistor being connected to the positive terminal of said source,
- a sawtooth oscillation generator comprising a first thermionic tube having a cathode, grid and anode, a variable resistor connected between said cathode and grid, a second thermionic tube having a cathode, grid, anode and an electron path between the cathode and anode of said second thermionic tube, a source of direct current supply voltage, a serially connected resistor and condenser, said serially connected resistor being connected to the positive terminal of said source, a connection from the junction point of said serially connected resistor and said condenser to the anode of said first thermionic tube, a capacity coupling from said junction to the grid of said second thermionic tube, a resistor connected between the grid of said second thermionic tube and the negative terminal of said source, a transformer having a primary and secondary winding with said primary winding connected in series with said source and the cathode of said second thermionic tube, a direct connection between said condenser and
- a sawtooth oscillation generator comprising a first thermionic tube having a cathode, grid and anode, a variable resistor connected between said cathode and grid, a second thermionic tube having a cathode, grid, anode and an electron path between the cathode and anode of said second thermionic tube, a source of direct current supply voltage, a serially connected resistor and condenser, said serially connected resistor being connected to the positive terminal of said source, a connection from the junction point of said serially connected resistor and said condenser to the anode of said first thermionic tube, a capacity coupling from said junction to the grid of said second thermionic tube, a resistor connected between the grid of said second thermionic tube and the negative terminal of said source, a transformer having a primary and secondary winding with said primary winding connected in series with said source and said electron path, a direct connection between said condenser and said primary winding, a deflection
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- Details Of Television Scanning (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB5285/38A GB511847A (en) | 1938-02-19 | 1938-02-19 | Improvements in or relating to electrical oscillation generators |
Publications (1)
Publication Number | Publication Date |
---|---|
US2248975A true US2248975A (en) | 1941-07-15 |
Family
ID=9793231
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US255795A Expired - Lifetime US2248975A (en) | 1938-02-19 | 1939-02-11 | Electrical oscillation generator |
Country Status (3)
Country | Link |
---|---|
US (1) | US2248975A (de) |
DE (1) | DE944572C (de) |
GB (1) | GB511847A (de) |
Cited By (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2431766A (en) * | 1943-09-10 | 1947-12-02 | Rca Corp | Modified sweep circuit for cathode-ray tubes |
US2435598A (en) * | 1943-12-28 | 1948-02-10 | Bell Telephone Labor Inc | Electric pulse delay circuit |
US2512305A (en) * | 1945-12-15 | 1950-06-20 | Philco Corp | Electrical system |
US2559316A (en) * | 1948-03-22 | 1951-07-03 | Louis W Parker | Sweep circuit for television receivers |
US2589833A (en) * | 1945-05-03 | 1952-03-18 | Us Sec War | Pulse discriminator circuit |
US2591249A (en) * | 1946-06-28 | 1952-04-01 | Belmont Radio Corp | Transformerless saw-tooth current generator |
US2602896A (en) * | 1947-10-16 | 1952-07-08 | Marconi Wireless Telegraph Co | Saw-tooth wave generator |
US2603747A (en) * | 1944-04-24 | 1952-07-15 | Sperry Corp | Sweep circuit |
US2627031A (en) * | 1946-11-27 | 1953-01-27 | Rca Corp | Relaxation oscillator |
US2728028A (en) * | 1952-08-23 | 1955-12-20 | Rca Corp | Electron beam deflection apparatus |
US2729766A (en) * | 1951-02-07 | 1956-01-03 | Rca Corp | Electronic oscillator circuits |
US2764681A (en) * | 1953-08-19 | 1956-09-25 | Gen Electric | Frequency stabilized and controlled oscillatory system |
US2806176A (en) * | 1953-12-31 | 1957-09-10 | Rca Corp | Deflection circuit |
US2824230A (en) * | 1954-08-02 | 1958-02-18 | Thompson Prod Inc | Sweep circuit |
US2831917A (en) * | 1953-10-30 | 1958-04-22 | Westinghouse Electric Corp | Color phase alternation system |
US2873406A (en) * | 1954-02-12 | 1959-02-10 | Rca Corp | Color television switching circuits |
US2905868A (en) * | 1954-09-02 | 1959-09-22 | Gen Motors Corp | Self oscillating light controlled circuit |
US2923851A (en) * | 1956-12-26 | 1960-02-02 | Clayton A Washburn | Wave-form generator |
US3005183A (en) * | 1951-01-10 | 1961-10-17 | Fred M Mayes | Underwater transmitter |
US3222589A (en) * | 1956-03-14 | 1965-12-07 | Lloyd C Poole | Electrical control system for welding apparatus |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE648185C (de) * | 1937-07-24 | Banning A G J | Kuehlvorrichtung fuer die Laufzapfen der Walzen von Walzwerken |
-
1938
- 1938-02-19 GB GB5285/38A patent/GB511847A/en not_active Expired
-
1939
- 1939-02-11 US US255795A patent/US2248975A/en not_active Expired - Lifetime
- 1939-02-21 DE DEE2328D patent/DE944572C/de not_active Expired
Cited By (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2431766A (en) * | 1943-09-10 | 1947-12-02 | Rca Corp | Modified sweep circuit for cathode-ray tubes |
US2435598A (en) * | 1943-12-28 | 1948-02-10 | Bell Telephone Labor Inc | Electric pulse delay circuit |
US2603747A (en) * | 1944-04-24 | 1952-07-15 | Sperry Corp | Sweep circuit |
US2589833A (en) * | 1945-05-03 | 1952-03-18 | Us Sec War | Pulse discriminator circuit |
US2512305A (en) * | 1945-12-15 | 1950-06-20 | Philco Corp | Electrical system |
US2591249A (en) * | 1946-06-28 | 1952-04-01 | Belmont Radio Corp | Transformerless saw-tooth current generator |
US2627031A (en) * | 1946-11-27 | 1953-01-27 | Rca Corp | Relaxation oscillator |
US2602896A (en) * | 1947-10-16 | 1952-07-08 | Marconi Wireless Telegraph Co | Saw-tooth wave generator |
US2559316A (en) * | 1948-03-22 | 1951-07-03 | Louis W Parker | Sweep circuit for television receivers |
US3005183A (en) * | 1951-01-10 | 1961-10-17 | Fred M Mayes | Underwater transmitter |
US2729766A (en) * | 1951-02-07 | 1956-01-03 | Rca Corp | Electronic oscillator circuits |
US2728028A (en) * | 1952-08-23 | 1955-12-20 | Rca Corp | Electron beam deflection apparatus |
US2764681A (en) * | 1953-08-19 | 1956-09-25 | Gen Electric | Frequency stabilized and controlled oscillatory system |
US2831917A (en) * | 1953-10-30 | 1958-04-22 | Westinghouse Electric Corp | Color phase alternation system |
US2806176A (en) * | 1953-12-31 | 1957-09-10 | Rca Corp | Deflection circuit |
US2873406A (en) * | 1954-02-12 | 1959-02-10 | Rca Corp | Color television switching circuits |
US2824230A (en) * | 1954-08-02 | 1958-02-18 | Thompson Prod Inc | Sweep circuit |
US2905868A (en) * | 1954-09-02 | 1959-09-22 | Gen Motors Corp | Self oscillating light controlled circuit |
US3222589A (en) * | 1956-03-14 | 1965-12-07 | Lloyd C Poole | Electrical control system for welding apparatus |
US2923851A (en) * | 1956-12-26 | 1960-02-02 | Clayton A Washburn | Wave-form generator |
Also Published As
Publication number | Publication date |
---|---|
GB511847A (en) | 1939-08-25 |
DE944572C (de) | 1956-06-21 |
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