US2462078A - Oscillation generator - Google Patents

Oscillation generator Download PDF

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Publication number
US2462078A
US2462078A US615417A US61541745A US2462078A US 2462078 A US2462078 A US 2462078A US 615417 A US615417 A US 615417A US 61541745 A US61541745 A US 61541745A US 2462078 A US2462078 A US 2462078A
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Prior art keywords
pulses
valve
grid
multivibrator
cathode
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Expired - Lifetime
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US615417A
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English (en)
Inventor
Earp Charles William
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International Standard Electric Corp
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International Standard Electric Corp
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
    • H03K3/02—Generators characterised by the type of circuit or by the means used for producing pulses
    • H03K3/04—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of vacuum tubes only, with positive feedback
    • H03K3/05—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of vacuum tubes only, with positive feedback using means other than a transformer for feedback
    • H03K3/06—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of vacuum tubes only, with positive feedback using means other than a transformer for feedback using at least two tubes so coupled that the input of one is derived from the output of another, e.g. multivibrator
    • H03K3/08—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of vacuum tubes only, with positive feedback using means other than a transformer for feedback using at least two tubes so coupled that the input of one is derived from the output of another, e.g. multivibrator astable

Definitions

  • OS 0 ILLATION GENERATOR Filed Sept. 10, 1945 2 Sheets-Sheet 2 2.
  • 0 II is 2 l/Lrlwamrom L2 may 3/ 32 usr mm l8 3 v V O 0/9 3 many/5mm? Inventor CNHRLES. ⁇ MLLmM.EnRP.
  • the present invention relates to oscillation generators of the electrical multivibrator type, utilising a single multi-grid electron discharge device or valve having the electrodes intercoupled to perform the function of the two valves normally present in the well known orthodox multivibrator circuit.
  • the circuit arrangement oscillates between two conditions in which the relative potential difierences of two electrodes are reversed the one with respect to the other, the reversal being brought about by the application to an electrode of a voltage of opposite polarity to the biassing voltage already existing on that electrode.
  • Such an applied voltage may take the form of a voltage pulse generated in another part of the circuit so that the circuit functions continuously as an oscillator.
  • Such an oscillator may be synchronised to a train of pulses of suitable voltage polarity applied to an electrode so as to switch the circuit from one condition to the other, the timing of the synchronising pulse and of the generated pulse being suitably chosen.
  • the single valve type of multivibrator is inherently more stable in frequency than the plural valve version, particularly with regard to power supply fluctuations, but for certain purposes such as for producing pulses which are employed for opening a gating circuit, for example, for the selection of a particularly desired pulse train in a received signal to the exclusion of other pulse trains of the same or different frequencies and interferences, or for frequency dividing, the stability of the single valve type is still not sufiiciently good. It is the object of this invention to increase the stability of a single Valve continuously running multivibrator circuit of the type specified.
  • a stabilised electric multivibrator comprising a thermionic valve having in the order named, a cathode, first, second and third grid electrodes and an anode; an operating source therefore having a substantially constant unidirectional potential; first and second resistances connecting the positive terminal of the said source to the anode and first grid electrodes, respectively; a third resistance connecting the cathode to the negative terminal of the said source; a condenser connecting the anode to the first grid electrode; means for applying a constant positive potential to the third grid electrode with respect tothe negative terminal of the said source; a resonant circuit connected in series with the cathode; and means for deriving output pulses from the second grid electrode.
  • Fig. 1 shows a schematic circuit diagram of a multivibrator according to the invention
  • Figs. 2 and 3 show waveform diagrams used in explaining the action of Fig. 1;
  • Figs. 4 and 5 show respectively two examples of self-gated multivibrators according to the invention.
  • the multivibrator according to the invention shown in Fig. 1 comprises a pentode valve l energised by a high tension source intended to be connected to the terminals 2 and 3, the latter being the negative terminal which is preferably connected to ground.
  • the anode and screen grid of the valve I are connected to the positive terminal 2 through resistances 4 and 5 respectively.
  • the cathode is connected to ground through a resistance 6 and a parallel resonant circuit consisting of an inductance I and a condenser 8.
  • a resistance 9 is connected in series with a resistance potentiometer [0 between the terminals 2 and 3, and a by-pass condenser ll shunts the resistance 9.
  • the suppressor grid of the valve I is connected directly to the junction point of the resistances 9 and It.
  • the control grid is connected to the anode through a condenser l2- and to the moving contact of the potentiometer ill through a resistance l3. It is also connected to the anode of a diode M, the cathode of which is connected to the junction point of elements 9 and it.
  • An output terminal I5 is connected to the terminal I? is connected to the junction point of the elements 6 and 1 for applying synchronising pulses.
  • I8 is an additional ground terminal which may be used with IE or ll.
  • a terminal l9 connected to the anode is provided to enable synchronisin'g pulses to be applied, if desired, to the anode instead of to the cathode.
  • the action starts-at zero time, when'the-screen currentis large, andzthe anode voltage has its maximumvalue. Since the resistance i is several times larger than the resistance 5, the anode current will be small compared with the screen current, and the potential of the cathode will be determined mainly by the screen current. This cathoderpotential.should. beva little higher than the-suppressor grid potential: which isindicated.
  • nant circuit 1,. 8 is.inc1uded in series with the cathodethe. sharp downstrokes b of the cathode potential will. excite, theresonant circuit and will cause it to-ring.
  • the naturalfrequency oftheresonant circuit should preferably be from; five to tentimes the frequency of repetition desired for the pulses.
  • An alternating. voltage will be superposed on the cathodevoltage as shown in Fig. 3. Then the time at which the cathode volt-. age exceeds. the. suppressor gridvoltage at the. endof the cycleis precisely determined by the steep up-stroke at e: in Fig. 3 of the superposed.
  • the time interval between the. cathode. pulses is veryv accurately determined by the resonant circuit i; 8 audit the circuit'constants are chosen. so that a very short cathode pulse is produced a .very stable oscillation is. obtained.
  • the output pulses are preferably derived from the screen grid, and if very short'pulses' are “required, the pulsesfrom" the" screen grid may "be differentiated in knownmanner;
  • the potentiometer IO' provides acone venient fineadjustment of the multivibrator" frequency:
  • synchronising pulses Thee various possible methods of applying the synchronising pulses in either sense to any suitable valve electrode will be understood by those skilled in the art; but the preferred method is to apply the synchronising pulses in positive sense to terminal ll and thence to the cathode.
  • the synchronising pulses do not appreciably excite the resonant circuit, and if the repetition frequency of the oscillation when controlled is slightly lower than that of the synchronising pulse train, synchronisation takes place by the exact determination of the leading edges of the cathode pulses, the timing being slightly advanced.
  • An oscillator according to Fig. 1 may be used to remove moderate interference from a particular signal pulse train by adding a gating pentode valve to the suppressor grid to which are applied in positive sense short gating pulses derived by differentiation from the screen grid of the valve in Fig. 1.
  • the signal pulse train is applied to terminal ll of Fig.
  • the signal pulses are applied to the gating valve after a slight delay in order to ensure that the gate will always open in time.
  • the duration of the gating pulse may be adjusted by known methods so that the signal pulses will not be curtailed.
  • Fig. 4- shows a multivibrator of the kind described with reference to Figs. 1 to 3 to which has been added a self-gating arrangement by means of which false operation due to strong interference accompanying the synchronising pulses may be prevented.
  • the multivibrator is shown by the block 28 which comprises the elements shown in Fig. 1. Only the terminals which are used for connection to the gating circuit are shown, and are given the same designations as in Fig. 1.
  • has its anode connected to the positive high tension terminal 22 through an anode load resistance 23. It will be understood, of course, that a common high tension supply may be used, if desired, for the valve 2
  • the screen grid is connected directly to the terminal 22, and the cathods is suitably biassed positively by connection to the junction point of 'two resistances 24 and 25 connected in series between terminal 22 and the earth terminal 26.
  • a cathode by-pass condenser 21 shunts the resistance 25.
  • the synchronising pulses are applied to the input terminal 28 and thence through a blocking condenser 29 to the control grid of the valve 2
  • the pulses from the screen grid of the valve of the multivibrator 28 are applied through the terminal l5 and through a transformer 3
  • a suitable terminating resistance 33 is provided.
  • is connected through a blocking condenser 34 and terminal l9 to the anode of the valve I of the multivibrator 20 (see Fig. 1).
  • the elements 5 and I6 should be chosen to produce suitable short differentiated pulses which are inverted by the transformer 3
  • the positive pulses are suitably delayed (for example by about 100 microseconds) and are applied to the suppressor grid of the valve 2
  • Positive synchronising signals applied at the terminal 28 are amplified and inverted by the valve 2
  • is biassed so that it is normally blocked, but is unblocked by the pulses derived from the multivibrator itself.
  • the delay introduced by the network 32 should be such that when a synchronising pulse is due to arrive, the valve 2
  • the valve (Fig. 1) cannot be afiected by pulses or by any interfering signals except during the specified 10 microseconds interval. In this way interfering signals of large amplitude are practically prevented from pro ducing false operation and accurate synchronisation by the desired pulse train is ensured.
  • Fig. 4 which is shown in Fig. 5 is adapted for synchronising the multivibrator to a train of pulses, or for selecting a given train of pulses from other trains by automatic frequency control without directly controlling the times of emission of the generated pulses.
  • Fig. 5 which are the same as elements of Fig. 4 have been given the same designation numbers and will not be again described.
  • and the delay network -32 are not required in the case of Fig. 5 and have been omitted, the output terminal l5 of the multivibrator 20 being connected directly to the suppressor grid of the valve 2
  • the anode is connected to the terminal 22 through a winding 35 which is inductively coupled with the inductance element '1 of the multivibrator 20 as indicated in Fig. 5.
  • the stabilising resonant circuit is in this case a tuned transformer.
  • the elements I and 8 may be connected in the same way as in Fig. 1.
  • the elements 23 and 34 of Fig. 1 are of course not required in Fig. 5 and'have been omitted.
  • the output pulses from the multivibrator are preferably differentiated to produce short positive pulses alternately with negative pulses which are not used.
  • unblock the valve for theduration of the input pulses which are applied at terminal 28 as before, together with any interfering signals which may be mixed therewith. Pulses which coincide with the unblocking pulses appear in the anode circuit and are applied-to the tuned transformer l, 35. According to the manner in which the connections to the windings have been poled, these will advance or retard the phase of the ringing of the resonant circuit, so synchronising the multivibrator to the applied pulse train.
  • the unblocking pulses 7 are positive, they will correspond with the trailing edges of the pulses generated by the: suppressor grid of the valve i in the multivibrator 20, and therefore with the trailing edges of the cathode pulses. These trailing edges correspond in. time with the extreme negative peaks of the ringing voltage waves of the resonantcircuit "I, 8
  • the trailing-edges of the gating pulses can be made to correspond closely with the initial instants. of zero voltage of the ringing oscillations,- so that pulsesarriving from the valve 2! at such instants cause a quadrature drive to the ringing. circuit, and therefore they exert a phase advancing or retarding influence.
  • tion frequency of the pulses generated by the multivibrator when uncontrolled is supposed to be slightly lower than that of the synchronising pulse trains, then the transformer 1', 35 should be poled so that when such synchronising pulse rides on the sloping: trailing edge of the corresponding unblock-ing pulse, a quadrature phase advancing drive is applied to the ringing circuit and therefore the oscillationperiod will be slightl y shortened to maintain the synchronism.
  • gated pulses may retard the phase of the ringing I! circuit-.-
  • a second gating valve (not shown) is preferably providedwith the. gating pulses applied to the suppressor grid through a network including a suitable delay so that the gate may be fully opened for the whole periods of the pulses.
  • a stabilised electric multivibrator comprising a thermionic valve having in the order named
  • a cathode, first, second, and third grid electrodes and an anode an operating. source therefor having a substantially constant unidirectional potential; first and second resistances connecting the positive terminal of the said source to the anode and. first grid electrode respectively; a third resi'stance connecting the cathode to the negative terminal of the said source; a condenser connecting the anode to the first grid electrode; means for applying. a constant positive potential to the third: grid electrode with reference to the negative terminal of the said source; a resonant circuit connected inseries with the cathode; and means for deriving output pulses from the second grid electrode.
  • a multivibrator according to claim l comprising means for preventing the potential of the first grid electrode from becoming positive with respect to that of the third grid electrode.
  • a multivibrator according to claim 4 in which the said means comprises a diode having its anode connected to the first grid electrode and its cathode connected to the third grid electrode.
  • a multivibrator according to claim 1v com-- prising means for applying synchronising pulses to the cathode circuit.
  • a multivibrator including an inductive winding coupled to the said inductance, and means for applying synchronising pulses to the inductive winding.
  • a multivibrator according to claim 1 in cluding means for applying synchronising pulses to the anode.
  • a multivibrator including a gating valve having a cathode, anode, control grid. and suppressor grid, means for applying a blocking bias to the said gating valve, means for applying a train of input pulses to the control grid of the gating valve, means for applying output pulses from the gating valve to synchronise the multivibrator, and means for applying output pulses from the multivibrator to unblock the gating valve to enable it to admit each input pulse when it is due to arrive.
  • a multivibrator in which. the means for applying the output pulses from the gating valve comprises means for conheating the anodes of the multivibrator andgat-- ing valves, and in. which the means for applying pulses to unblock the gating valve comprises a delay network connected between the second grid electrode of the multivibrator valve and the suppressor grid of. the gating valve.-
  • a multivibrator in which the means for applying the output pulses from the gating valve comprises means for inductively coupling the anode of the gating valve to the said resonant circuit, and in which the means for applying pulses to unblock the gating valve comprises means for connecting the second grid electrode of the multivibrator valve to the suppressor grid of the gating valve.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
US615417A 1944-09-15 1945-09-10 Oscillation generator Expired - Lifetime US2462078A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2610298A (en) * 1947-12-26 1952-09-09 Gen Electric Stabilized saw tooth oscillator
US2620443A (en) * 1948-05-01 1952-12-02 Emi Ltd Circuits for generating electrical oscillations of sawtooth waveform
US2653232A (en) * 1950-06-06 1953-09-22 Pierce W Siglin Range measuring apparatus
US2698400A (en) * 1947-06-03 1954-12-28 Sylvania Electric Prod Generator for dynamic focusing of cathode ray tubes
US2706247A (en) * 1949-10-14 1955-04-12 Jacobs Means and method for storing information in digital computers

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2199278A (en) * 1936-11-16 1940-04-30 Western Electric Co Electron discharge device
US2235131A (en) * 1939-10-25 1941-03-18 Hazeltine Corp Saw-tooth wave generator
US2255403A (en) * 1939-03-30 1941-09-09 Hazeltine Corp Periodic wave repeater
US2277000A (en) * 1940-09-17 1942-03-17 Philco Radio & Television Corp Synchronizing system
US2288554A (en) * 1939-06-05 1942-06-30 Philco Radio & Television Corp Synchronizing system and method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2199278A (en) * 1936-11-16 1940-04-30 Western Electric Co Electron discharge device
US2255403A (en) * 1939-03-30 1941-09-09 Hazeltine Corp Periodic wave repeater
US2288554A (en) * 1939-06-05 1942-06-30 Philco Radio & Television Corp Synchronizing system and method
US2235131A (en) * 1939-10-25 1941-03-18 Hazeltine Corp Saw-tooth wave generator
US2277000A (en) * 1940-09-17 1942-03-17 Philco Radio & Television Corp Synchronizing system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2698400A (en) * 1947-06-03 1954-12-28 Sylvania Electric Prod Generator for dynamic focusing of cathode ray tubes
US2610298A (en) * 1947-12-26 1952-09-09 Gen Electric Stabilized saw tooth oscillator
US2620443A (en) * 1948-05-01 1952-12-02 Emi Ltd Circuits for generating electrical oscillations of sawtooth waveform
US2706247A (en) * 1949-10-14 1955-04-12 Jacobs Means and method for storing information in digital computers
US2653232A (en) * 1950-06-06 1953-09-22 Pierce W Siglin Range measuring apparatus

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CH273520A (fr) 1951-02-15

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