US2085424A - Synchronization system - Google Patents

Synchronization system Download PDF

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Publication number
US2085424A
US2085424A US63473A US6347336A US2085424A US 2085424 A US2085424 A US 2085424A US 63473 A US63473 A US 63473A US 6347336 A US6347336 A US 6347336A US 2085424 A US2085424 A US 2085424A
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United States
Prior art keywords
anode
grid
phase
current
positive
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Expired - Lifetime
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US63473A
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English (en)
Inventor
Goddard De Witt Rugg
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RCA Corp
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RCA Corp
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Filing date
Publication date
Priority to BE419954D priority Critical patent/BE419954A/xx
Application filed by RCA Corp filed Critical RCA Corp
Priority to US63473A priority patent/US2085424A/en
Priority to DER98571D priority patent/DE714083C/de
Application granted granted Critical
Publication of US2085424A publication Critical patent/US2085424A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
    • H04H20/65—Arrangements characterised by transmission systems for broadcast
    • H04H20/67—Common-wave systems, i.e. using separate transmitters operating on substantially the same frequency
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
    • H03L7/00—Automatic control of frequency or phase; Synchronisation
    • H03L7/06—Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop

Definitions

  • AREA a /4.5% AREA b 50% AREA 85.5% AREA 0 /00% mo ⁇ : 75% 50% 25% a 1 i +a+ H 6 m0 S T 4 75 w & 5 7055 g. 7085M v E: 0 D
  • the present invention relates to synchronizing circuits, and more particularly to an arrangement for maintaining synchronism of frequency and/or phase between a plurality of broadcasting stations.
  • the present invention provides an improved circuit arrangement which is sensitive to the phase difference between the carriers of two transmitting stations to maintain the carriers at the same frequency and approximately in phase.
  • the invention consists in separately receiving at the control station the two carrier frequencies of the stations it is desired to synchronize and individually beating each of the received waves with locally generated oscillations to produce conveniently low tonal oscillations, and comparing the two locally produced tones by a phase detector to control the phase of the oscillations generated at one transmitter with respect to that of the other.
  • a feature of the invention is the grid controlled glow discharge device phase detector employed for determining phase differences in the received waves.
  • Fig. 1 shows a schematic drawing of two transmitting stations A and B whose transmitted carriers are accurately synchronized by means of control station C;
  • Fig. 2 illustrates schematically the circuit arrangement for control station 0;
  • Figs. 3-8 inclusive, are graphs illustrating the relation between anode current and phase displacement of the phase detector of the system of Fig. 2, and will be referred to in explaining the operation of the phase detector;
  • Fig. 9 illustrates another type of phase detector which can be used to replace the special type of phase detector of Fig. 2.
  • Fig. 1 there are shown schematically two transmitting stations A and B whose carrier oscillations it is desired to synchronize with respect to one another as to phase and frequency.
  • Each station is provided with an antenna for radiating the carrier oscillations.
  • the apparatus at both of these stations may take any well 5 known form, and is herein shown conventionally in box form.
  • Station C is the control station employing two receivers E and F, each of which has a directive antenna, as illustrated, for separately picking up the radiations from one of the transmitters, either A or B.
  • These receivers pass the received energy to a phase detector, and the latter controls the frequency adjusting mechanism of transmitter B over a transmission line D.
  • station C comprises two receivers E and F which have respectively directive antennae E and F.
  • Directive antenna E is pointed at one of the stations A and B and directive antenna F is pointed at the other station for respectively collecting only the energy radiated from that one station toward which it is pointed.
  • the receivers E and F are both fed by a local oscillator O of suitable frequency for producing in their respective outputs a beat signal of suitable low frequency, such as 500 cycles.
  • transformers H and K which are in circuit with a special phase detector comprising two gaseous conduction tubes M and N, each of which is provided with a grid GR, an anode AN, and a cathode CA suitably arranged to keep the carrier oscillations of the two transmitters A and B in phase, as will appear more fully hereinafter.
  • Transformers H and K in the outputs of receivers E and F are each provided with two secondary coils, one feeding the grid circuit of one of the grid controlled glow discharge devices while the other coil feeds the anode circuit of the other grid controlled glow discharge device.
  • Thyratron devices are known in the art by the trade-name Thyratron and are characterized by the fact that the grid acts as a trigger when supplied with a suitable positive potential, after which the grid loses control and the device continues to produce a flow of current in the anode circuit until such time as the anode current is either cut off or reduced to a potential below a critical value.
  • Winding G of the relay is in the anode circuit of device M and winding L in the anode circuit of device N. It should be observed at this time that there are no bias batteries provided for the grids and anodes of the thyratron tubes.
  • the grid resistors Z and W and the anode resistors Z and W prevent the grids and anodes from drawing excessive current during the positive portions of their voltage swings, as will appear more fully later. As long as equal currents flow through these windings, the armature or tongue T of relay R will remain centered, as shown, without engaging either of the two contacts.
  • tongue T will engage the contact associated with the winding drawing the greater amount of current, in this case L, thus sending a potential, either positive or negative, over the transmission line D, shown in dotted lines, to the frequency adjustment mechanism at the transmitting station B. In the example assumed, a negative potential would be sent over the line D. If, on the other hand, thyratron M has more current flowing in its output winding G than thyratron N, then tongue T will be attracted in the upper direction and a positive potential will flow out over the line D to station B.
  • thyratron M is subjected to an alternating anode voltage and an alternating grid voltage.
  • the instantaneous grid and anode voltages during one complete cycle of the 500 cycle beat notes. As the grid starts to swing from zero volts to ward its maximum negative value, the anode starts to swing from zero volts toward its maximum positive value. During this quarter cycle no anode current can flow as the grid remains negative thereby keeping the anode current cut off.
  • tube N The situation for tube N is different.
  • the grid leads the anode in its phase by a small amount so that as the anode starts from zero voltage towards its positive swing, the grid has already become negative, with the result that no current flows in the anode circuit.
  • the grid passes through its negative swing and comes back to zero before the anode has quite completed its positive swing. Therefore, anode current flows for the remainder of its positive swing.
  • the negative swing of the anode it, of course, passes no current.
  • the total result of this is to make arelatively large average current flow through relay winding G and a relatively small current flow through relay winding L. This would raise the armature R causing it to engage the upper contact sending a voltage of such polarity to the controlled transmitter as to bring it back in phase with the master transmitter.
  • Fig. 3 shows the behavior of tube M with varying phase displacements between the two transmitters.
  • the abscissa indicates degrees of lead (-1-) or lag of the signal picked up on antenna E with respect to the sign-a1 picked up on antenna F.
  • the ordinate represents the percent of each positive half cycle of the 500 cycle beat note that anode current flows. For instance, suppose the signal picked up on antenna E lags F by 270, then the 500 cycle voltage in-H lags that in K by 270.
  • the anode of this tube M starts upward on its positive swing, its grid being 270 behind in phase is at the maximum of its negative swing, therefore the tube cannot pass anode current until 90 later or when the grid passes through zero.
  • Tube M has been treated with some detail to show how various phase relations of the grid and anode voltages affect the anode current.
  • Tube N is subjected to similar conditions. Due to the fact that the grid and anode voltages are exact-' ly out of phase with the corresponding elements of tube M, the curve of time of flow of plate current versus phase difference of antenna signals assumes a different shape. This curve is shown in Fig. 4. In order to check this curve, let us assume one condition in which E and F are out of phase and trace the behavior of the anode current.
  • Fig. 5 shows both curves superimposed. It is evident from this figure that there are two values of phase displacement that can be used to control the adjustable transmitter. One is at zero degrees and the other is at 180. The 180 setting has been assumed as the more desirable as the greater the phase displacement from this value, the greater the correcting force on the relay GL. If this setting is used, then the setting at zero phase displacement will give reverse control. This offers no handicap as the controlled transmitter would merely be kept off exact synchronism until the phases once more passed through 180 relation at which point the control would take hold again.
  • Fig. 8 shows a composite curve comprising the anode current characteristic of both thyratrons with respect to phase displacement of the twoincoming signals.
  • the anode may swing a few volts positive without anode current flowing assists in correcting the first erroneous assumption, for under certain conditions described above, it allows the grid to assume a negative potential of suflicient magnitude to prevent anode current from flowing before the anode voltage has reached a high enough voltage to start anode current.
  • the polarity sensitive frequency corrector for station E is merely illustrative of any type of apparatus which may be used for effecting the frequency adjustment.
  • a motor Q which may be operated in either of two directions, depending upon the application of the polarity to the line D to adjust a variable condenser U for regulating the frequency of the oscillator Y, which is controlled as to frequency by a frequency controlling element such as a piezo-electric crystal PE.
  • the output of oscillator Y feeds any suitable type of transmitting circuit arrangement through a blocking condenser X.
  • the transmitting circuit shown comprises a buffer amplifier BA feeding a power amplifier PA in whose output circuit is an antenna.
  • a modulator circuit MO which is responsive to the energy impressed on the microphone V and audio frequency amplifier AF for modulating the output of the power amplifier.
  • the invention is not limited to any one type of frequency correction circuit since, if desired, other types of frequency correcting mechanism may be used, such as are described in United States Patent No. 2,027,196, granted January 7, 1936, to Arthur Pfister.
  • a particularly desirable type of electro-mechanical drive for condenser V is described in my copending application Serial No. 11,915, filed March 20, 1935.
  • Fig. 9 illustrates another type of phase corrector which can be used instead of that shown in Fig. 2.
  • This corrector dilfers from that of Fig. 2 mainly in the use of high vacuum tubes M, N and the provision of transformers H, K which have single secondary windings.
  • the two tubes M and N in the manner illustrated in the drawings, constitute a pair of differential detectnrs.
  • the electromotive force of given frequency coming in over transformer K is combined with the output electromotive force from transformer H on the grid circuits of the vacuum tubes M, N.
  • the method of synchronization which consists in producing two radio waves whose frequencies are to be synchronized, radiating said waves, separately receiving each of said radiated waves, and separately beating said received waves with a third wave to obtain resultant beat notes of audible frequencies, and controlling the frequency of one of the waves to be synchronized in accordance With the difference between said audible frequencies.
  • a phase detector comprising a first transformer and a second transformer each having a single primary and two secondary windings, a first and second gaseous conduction device each having an anode, a cathode, and a grid, means for connecting the grid and cathode of said first device across one of the secondary windings of said first transformer, and means for connecting the grid and cathode of the other device across the correspondingly located secondary winding of the second transformer, and means for conmeeting the cathode and anode of the second device to the other secondary winding of the first transformer, and the anode and cathode of the first device to the other secondary Winding of the second transformer, a polarized relay having two windings, one of which is serially arranged in the anode circuit of one device and the other of which is serially arranged in the anode circuit of the other device, said relay having an armature and two oppositely disposed contacts arranged to be alternately engaged by said armature, means for applying a positive potential to

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Particle Accelerators (AREA)
US63473A 1936-02-12 1936-02-12 Synchronization system Expired - Lifetime US2085424A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
BE419954D BE419954A (enrdf_load_stackoverflow) 1936-02-12
US63473A US2085424A (en) 1936-02-12 1936-02-12 Synchronization system
DER98571D DE714083C (de) 1936-02-12 1937-02-13 Anordnung zur Synchronisierung von Gleichwellensendern

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US63473A US2085424A (en) 1936-02-12 1936-02-12 Synchronization system

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US2085424A true US2085424A (en) 1937-06-29

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US63473A Expired - Lifetime US2085424A (en) 1936-02-12 1936-02-12 Synchronization system

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BE (1) BE419954A (enrdf_load_stackoverflow)
DE (1) DE714083C (enrdf_load_stackoverflow)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2431018A (en) * 1943-03-26 1947-11-18 Ibm Sound detection system and apparatus
US2536255A (en) * 1949-01-29 1951-01-02 Rca Corp Radio carrier synchronization system
US2599643A (en) * 1949-01-24 1952-06-10 Rca Corp Radio transmission system
US2644942A (en) * 1949-03-18 1953-07-07 Rca Corp Television carrier control system
US2671897A (en) * 1945-07-03 1954-03-09 Roger B Woodbury Automatically synchronized long range navigation pulse transmitter
US2830241A (en) * 1954-07-21 1958-04-08 Turck Jean Telecontrol device
US2838753A (en) * 1950-09-07 1958-06-10 Decca Record Co Ltd Radio range-indicating systems
US2890451A (en) * 1955-05-04 1959-06-09 Seismograph Service Corp Radio location system
US2945224A (en) * 1957-07-08 1960-07-12 Itt Phase and amplitude correction system and navaglobe beacon utilizing same
US2952016A (en) * 1957-07-12 1960-09-06 Itt Sampling and correcting system
US3045232A (en) * 1956-03-30 1962-07-17 Sanders Associates Inc Electronic velocity indicator apparatus

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE964690C (de) * 1952-05-04 1957-05-29 Telefunken Gmbh Verfahren zur Phasensynchronisierung der von zwei oertlich verschieden gelegenen, fernen Impuls-Sendern abgegebenen Impulse gleicher Impulsfolgefrequenz

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2431018A (en) * 1943-03-26 1947-11-18 Ibm Sound detection system and apparatus
US2671897A (en) * 1945-07-03 1954-03-09 Roger B Woodbury Automatically synchronized long range navigation pulse transmitter
US2599643A (en) * 1949-01-24 1952-06-10 Rca Corp Radio transmission system
US2536255A (en) * 1949-01-29 1951-01-02 Rca Corp Radio carrier synchronization system
US2644942A (en) * 1949-03-18 1953-07-07 Rca Corp Television carrier control system
US2838753A (en) * 1950-09-07 1958-06-10 Decca Record Co Ltd Radio range-indicating systems
US2830241A (en) * 1954-07-21 1958-04-08 Turck Jean Telecontrol device
US2890451A (en) * 1955-05-04 1959-06-09 Seismograph Service Corp Radio location system
US3045232A (en) * 1956-03-30 1962-07-17 Sanders Associates Inc Electronic velocity indicator apparatus
US2945224A (en) * 1957-07-08 1960-07-12 Itt Phase and amplitude correction system and navaglobe beacon utilizing same
US2952016A (en) * 1957-07-12 1960-09-06 Itt Sampling and correcting system

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Publication number Publication date
DE714083C (de) 1941-11-21
BE419954A (enrdf_load_stackoverflow)

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