US2434273A - Wave translating system - Google Patents

Description

Jan. 13, 1948. R. w. KETCHLEDGES; 294345273 WAVE TRANSLA'IING SYSTEM Filed Jan. 21, 1943 FREOUEiW-Y DOUBLE? d POL A5317? REVERSER l/WENTOR R. W KETCHLEDGE ATRDRAET rectifier as a control wave.

Patented Jan. 13, 1948 WAVE TRANSLATING SYSTEM Raymond W. Ketchledge, New York, N. Y., assignor to Bell Telephone Laboratories, Incor- Y., a corporation of New porated, New York, N

York

Application January 21, 1943, Serial No. 473,083

8 Claims.

This invention relates to wave translation and especially to frequency translation.

An object of the invention is to produce direct current of polarity or sign varying in accordance with the polarity or phase-sign of an alternating current wave which at times has polarity reversals, i. e., phase changes of 180 degrees. The alternating current wave having the polarity reversals will be called the signal wave.

It is also an object of the invention to obtainreliable operation of devices responsive to direct current, as for example vacuum tubes, switches and clutches, in opposite senses in accordance with the polarity of an alternating current Wave.

In one specific application of the invention the direct current device to be operated is a differential relay. The signal wave is applied to a rectifier. A reference wave is applied to the It is of the same frequency as the signal wave but of constant polarity and preferably always either substantially in phase coincidence with the signal wave or in phase opposition to the signal wave, The reference wave so controls the rectifier that the rectifier passes to each of the differential windings of the relay substantially none of the reference wave and only time elements of the signal wave that are determined by the reference wave. For example, when the signal Wave is in phase with the reference wave the rectifier passes to one winding of the differential relay, through a low-pass filter and direct current amplifier if desired, only the positive half-cycles of the signal wave, and passes to the opposed winding of the relay, through a low-pass filter and direct current amplifier if desired, only the negative half-cycles of the signal wave; and when the phase of the alternating current signal reverses, so that the phase difference between the signal wave and the reference wave is 180 degrees, the rectifier passes to said one winding only the negative half-cycles of the signal wave and passes to said opposed winding only the positive half-cycles of the signal wave.

Other objects and features of the invention will be apparent from the following description and claims,

The single figure of the drawing shows diagrammatically a system embodying the invention in the specific form referred to above. However, the invention is not limited to this specific circuit.

Source l supplies alternating current, for instance a sine wave having a frequency of 400 cycles per second, to a device 2 which doubles the resulting BOO-cycle sine wave of alternating current at time intervals which may be long compared to a period of SOD-cycle wave, as for example many times as long or even of any desired greater order of magnitude. The intervals may be regular or irregular, that is, equal or unequal, and the reversals may take place at any desired relative times or points (i. e., at corresponding points or at different points) in the particular cycles (of the BOO-cycle wave) during which they occur. The device 2 may be, for example, a harmonic producing device such as a non-linear element, for example, a rectifier, and a phase reversing device, for instance a switch for reversing the connection between two pairs of contacts, or for instance a Wheatstone bridge whose unbalance in opposite directions may cause phase reversals.

The 800-cycle signal wave having the polarity reversals passes through transformer 3, tuned to that frequency by condenser 4, to the grid circuit of amplifier tube 5 which amplifies the signal. Across the primary winding of transformer 3 is a 200-ohm resistor 6 which is used for impedance matching to the frequency doubler and polarity reverser 2. A .S-megohm resistor 7 in the grid lead of tube 5 prevents appreciable loading of transformer 3 when the 800-cycle signal wave is large enough to cause grid current fiow in tube 5. The filament heating current for tube 5 is supplied from 24-volt battery I through four ballast lamps H in a series, a 3-ohm grid bias resistor l2 for tube 5, and a ballast lamp [3. The filament is in parallel with the filaments of balanced amplifier tubes 14 and i referred to hereinafter.

The amplified 800-cycle wave with the polarity reversals is applied to a rectifier therefor, comprising, for example, rectifying elements of the dry contact type, for instance, copper-oxide rectifying elements 2|, 22, 23, 24 connected and poled as shown, or for example thermonic diodes, for instance, 6H6 vacuum tubes, This wave is applied from tube 5 across element 2| through a circuit including the plate of tube 5, a .Z-microfarad condenser for stopping direct current, a .3-megohm resistance 3!, element 2|, coil 35 of secondary winding 34 of transformer 32, conductor 40, lamp I3, resistance l2, and the cathode of tube 5. The BOO-cycle wave from amplifier 5 is applied across element 22 through a circuit including the the plate of tube 5, condenser 30, resistance 3!, element22, coil 36 of winding 34, conductor 48], lamp l3, resistor l2 and the oaththe frequency and produces phase reversals of, ode of tube 5. The 800-cycle wave from amplifier is applied across element 23 through a circuit including the plate of tube 5, condenser 30, a .3- megohm resistance 4|, element 23, coil 36 of winding 34, conductor 40, lamp l3, resistance l2, and the cathode of tube 5. The BOO-cycle wave from amplifier 5 is applied across element 24 through a circuit .includingthe plate of tube 5, condenser 39, resistance 4|, element 24,'coil 35 of winding 34, conductor 4, lamp l3, resistance |2, and the cathode of tube 5.

Elements 2|, 22, 23 and 24 areal- ikaandncoils 35 and 36 are alike. Elements 2| and 22 connecting points 27 and 28 form two adjacent balancing arms of a balanced wheatstonabridge,

with coils 36 and 35 forming the respectively-op posite ratio arms. A diagonal of this bridge has its terminals at point and the :gronndedtcenter point 26 of winding 34. This diagonal includes resistance 3|, condenser 30, the plate=cathode path in tube 5, resistance |2, lamp l3 and con- ;ductor fll. This diagonal applies the signal wave 'from tube 5 acrosscorners'25 and-"26 of the-bridge. Winding 34 applies-across the other cornersfl'l and 28 of the bridge an'BOO-cycIe'reference' wave as pointed out hereinafter,

Elements ZS-and 24iformztwo adjacent ratio arms or a second balanced Wheatstone bridge, with 00115 35 and 36 forming ithei'res-pectively opposite ratio arms. A diagonal of thisi'bri'dge iterminates at points 129- and 26. .This diagonal -includes"resistance 4 condenser 130, the platecathode path in tube'5;'resistance I2, lamp l3'and conductor 40. This diagonal applies the signalwave from tube '5 across corners 29;and26 -of the bridge. iThe othercorners are 21 and-'28.

As just :noted,'winding 34 applies :across "the KpointsT-21and28 a referencewave of the same frequency as the signal wave, i. e., 800 cycles per .second.

'The reference wave, however, .isof constant polarity and preferably; for maximum sensitivity of therectifier, has its zero points occur atsubstantially the sameinstants .at whichthexzero values, of. the signal wave occur. Thatzis; prefer- 1 ably the reference Wave is always either in;phase with' the signal wave or in phase opposition to the :signalzwave. 'The reference waveoisinducediin .zwinding 34 by pulses 'of 'direct'currentzin :coils 31 and '38 of winding33of transformeri32. These :coils are alikeand are included in..afrequency Jdoubler and voltagev doubling rectifier devicei.50.

The device comprises :also two.like :groups of rectifying elements 5| and 52,v for instance, dry contact rectifying elementswhich-may be copper-oxide rectifiers or selenium rectifiers,for

example, and further comprises two likecondensers' 53 and 54. "Voltagefrom the'400*cycle 'source issupplied through conductorsf5'l" and -58 across pointsi 55 and 56 of. the 'device .50. The

'alternating current source alternately charges condensers53 and-"54 through the rectifying: elements'5l and '52, respectively, and maintainsa "directcurrent voltage across each-condenser approximately equal to thespeak value ofthe alter- The condensers form-a rent source This direct current'voltage-may be,If0rexample, 40 volts. This voltagegadded to that of the Z l-volt battery It, supplies the-plate and screen grid currents for-tubes 5,"|4 and 5,'-

point 51 being connected directly to the screen grids of all of the tubes, and being connected to the plate of tube 5 through inductance 59 and to the plates of tubes l4 and I5 through like differential windings 6| and 62 of an electromagnetically operated device 60, for example, a direct current differential polar relay. The relay tongue "or"armature-64-is an extension of a'fiat spring 65 rigidly fastened to permanent magnet 66, and extends between the north and south poles N and -S..of.themagnet to cooperate with the fixed contacts 61 and 68. The windings BI and 62 may be mounted for supported around the armature, which they magnetize. The tongue 64 is normally'biased byspring 65 to neutral or non-contacting position between contacts 61 and 68, with the direct-currentsiin.windings 6| and 62 equal. The tongue is operated to engage one of the contacts, -forciosing a circuit through that contact and the tongue, when the direct current in winding 8| exceeds that in:winding:52,zand is operated to engage the other .contact :for closing a circuit ':-through 'the .-latter contactand the tongue, when 'the direct current in winding; 62 exceeds" that in win'ding i I.

-'-The-igri'd andicathode of tube M are connected across a (.05-micrdfarad :condenser and 1 the grid and catho'deof tube |5are connected across a like condenser "12. The :v'oltage across .bridge rpointsc25xandz2fiis fed to the grid and cathode of tube |4 through a circuitincluding -a l-megohm rresistor 13, condenser'i||, resistance i2 and lamp |3; -and the-voltage across bridge points. 29 and 26 isfe'dto'the grid andcathode of tube l5 through a circuit including a resistor 14 :which is a duplicate of resistor-I3,- condenser' l2, resistance |'2 and lamp 13. The tubes I4 and l5 are two like direct current amplifiers'forming a balanced direct current amplifier. Tube l t-amplifies" the direct current fed to its'grid =andcathodefrom bridge point i25 and-26; andtube|5 amplifies =the direct/current fed to its grid and cathode from bridge points 29 and 25. Resistanceflli and con- :denser'll form a low-pass filter, which may be *used to remove the ripple from the voltage fed to tube 14, leaving. only the direct current componentyand resistance 14 and condenser 12 function as a similar filter for the input to tube l5.

The-direct'current' voltage drop across resistance l2 and-lamp l3 supplies negative bias for the control. grid of tube |4 through 2| and-22 and to'the control gri'dof tube |5 through 23 and'24.

The resistances of coils 35 and 36 are'negligibly low "compared to resistance 3| or resistance 4| '(and to-resistance'13 or resistance"). Also; the impe'danceto alternatingcurrent of coils-35 and 36 between terminals 21 and 28 joinedtogethcr and terminal 26is low because the voltage from terminal-28 to 26 will'tend to equal thatfrom terminal126 .to' 21, 'due to the coupling between 'coils 35 and36.

,As.indica-te'd above, pulses of direct current through coils 31 and 38 induce in winding'34 an alternating voltage 015 800. cycles. per: second, that .is, thersecond harmonicof the 400-cycle .volt- 'windings 6 l and 62-of'relay- 60, substantially none of the 1 reference wave and only time :zlements of the signal wave that are determined by the reference wave.

For example, assuming the reference voltage and the signal voltage pass through their zero values at the same instants, and considering these voltages to be in phase when the instantaneous values of the signal potential at point 25 have the same sign as the corresponding instantaneous values of the reference potential at point 28, then with the signal voltage and the reference voltage in phase, during the alternate half-cycles of the signal wave in which the instantaneous signal potentials are positive at point 25 and at point 29 the reference wave acts as a negative biasing voltage on elements 2| and 22 and as a positive biasing voltage on elements 23 and 24. The reference wave thus causes the circuit between points 25 and 26 through 2| and 35 to be of high impedance (or effectively an open circuit as regards signal transmission from tube to tube l4) and causes the circuit between points 25 and 26 through 22 and 33 similarly to be eifectively an open circuit, so the positive potential of the signal is transmitted from 25 to the grid of tube M, to cause the current through winding 6| to be above its normal value; while at the same time the reference wave causes the circuit between 29 and 26 through 23 and 32 to be a circuit of negligible impedance or substantially a short-circuit and causes the circuit between points 29 and 23 through 24 and 35 to be substantially a short-circuit, so transmission of the positive potential of the signal from 29 to the grid of tube I5 is substantially prevented. Thus, the tongue of relay 60 engages one of the fixed contacts. In the intervening half-cycles of the signal wave, i. e., when the instantaneous signal potentials transmitted from tube 5 to point 25 and to point 29 are negative, the reference wave acts as a positive biasing voltage on elements 2| and 22 and a negative biasing voltage on elements 23 and 24, thus preventing the neg ative potential of the signal from affecting the potential of the grid of tube l4 and the current in winding 6| (which remains above its normal value because of the charge on condenser and causing the negative potential of the signal to reach the grid of tube i5 and reduce the current in winding 62 below its normal value and so increase the force of engagement of tongue 64 with the fixed contact just mentioned. Thus, the relay tongue remains against that contact as long as the signal is transmitted in phase with the reference wave. The relay may be too sluggish to follow even the individual pulses of direct current that windings 5| or 62 would receive in the absence of condensers H and 12.

On the other hand, with the phase of the signal reversed, so that the signal voltage and the reference voltage are in phase opposition, then it is during the alternate half-cycles of the signal wave in which the instantaneous signal potentials are negative at point 25 and at point 29 that the reference wave acts as a negative biasing voltage on elements 2| and 22 and as a positive biasing voltage on elements 23 and 24. The reference wave thus causes the negative potential of the signal to be transmitted from point 25 to the grid of tube i4 and prevents transmission of the negative potential of the signal from 29 to the grid of tube I5, so the tongue 24 engages the fixed contact opposite the one just mentioned. In the intervening half-cycles of the signal wave, i. e.. when the instantaneous signal potentials at point 25 and at point 29 are positive, the tongue likewise is in engagement with that contact: for the reference wave, acting as a positive biasing voltage on elements 2| and 22 and as a negative biasing voltage on elements 23 and 24, prevents the positive potential of the signal from being transmitted to the grid of tube l4 and causes it to be transmitted to the grid of tube l5.

In short, in the operation of the system, during alternate half-cycles of the reference wave (and so of the signal wave) the reference wave causes the diodes 2| and 22 to be substantially open circuits and the diodes 23 and 24 to be of negligibly low or substantially zero impedance; so point 25 assumes a positive or negative potential with respect to ground, depending on the polarity or phase of the signal wave at the time, and point 29 assumes substantially ground potential. In the intervenin alternate half-cycles the reference wave causes the diodes 23 and 24 to be substantially open circuits and the diodes 2| and 22 to be short-circuits; so point 29 assumes a negative or positive potential with respect to ground, depending on the polarity or phase of the signal wave at the time, and point 25 assumes substantially ground potential. Thus, when the signal wave has one polarity or phase the grid of tube 14 receives a resultant potential of one I sign and the grid of tube l5 receives a resultant potential of opposite sign, and for each grid the resultant potential is the reverse when the polarity or phase of the signal is the reverse. Consequently, tongue 34 is operated to one side or the other of its neutral position depending on the polarity of the signal wave or phase of the signal. The reference wave thus operates the diodes as a switching device, in synchronism with the signal voltage, to alternately short-circuit the input circuits of tubes M and I5 for periods equal to half-cycles of the signal wave. For maximum sensitivity of the system, the diode switch should be operated in phase or degrees out of phase with the signal wave (i. e., the reference voltage should pass through zero values at the same instants as the signal voltage). It should be noted that with the particular form of switching device shown the output voltage cannot exceed a certain limit determined by the magnitude of the reference wave; because if the signal wave across 25 and '26 and across 29 and 26 attempts to exceed one-half of the reference wave across 21 and 28, one of the diodes 22 or 2| will conduct with low impedance (at a time when the reference wave is attempting to bias it negatively) and will thereby prevent further rise of the voltage transmitted to tube l4, and one of the diodes 23 or 24 will conduct with low impedance (at a time when the reference wave is attempting to bias it negatively) and will thereby prevent further rise of the voltage transmitted to tube l5. However, although limiting may occur, there is no possibility for polarity reversal of the direct current voltage transmitted to tube M or tube i5 without a reversal of the polarity or phase of the signal wave applied to rectifier 2G, and the reference Wave amplitude only determines the maximum voltages obtainable as inputs to tubes i4 and i5. False operation of relay 60 cannot be caused by the signal wave amplitude being large, even if it be two or more times that of the reference wave. The rectifier 2 I, 22 is not sensitive to polarity but rather to time. That is, it passes current to its load device Id at times determined by the reference wave regardless of the sign of the signal voltage transmitted through condenser 30. The same may be said with ref- . erencerto rectifier 23, 24 and its load device l5.

Transmission of the reference voltage to tube i4 is prevented by balance of the bridge whose ratio arms include elements 2|, 22, 35 and 36. Similarly, transmission of the reference voltage to; tube 15 is prevented by balance of the bridge whoseratioarms include elements 23, 24, 35 and 3.8,

What is claimed is:

1., A wave translating system comprising a sourceof alternatingsignal current havin phase reversalsa direct currentresponsive load device, a path for connecting said source to said device, a source of, reference currentv of the frequency of said signal current, and a balanced Wheatstonezbridgecircuit shunted across said path including saidzsourceof reference current and having; one pair of. opposite corners connected to said path and having its other pair of opposite corners connected to said Source of reference current said. bridge circuit comprising a pair of ad- ,iacentarms in series forming a circuit connecting. said other pair of corners, each of said arms comprising a two-terminal rectifying element, and said rectifying elements being poled in the same direction in said circuit connecting said other pair ofcorners.

2. A system comprising control means controlled in: accordance with phase relations between an alternating current signal wave of reversible polarity and av reference wave, a direct current load device operable in opposite senses according to the polarity of the alternating current signal wave, a source for supplying said signal wave, and a circuit connecting said control means between saidxsourceand said load device including transmission apparatus responsive to direct current for controlling transmission from said. source to said load device, said system. further comprising a rectifying and frequency multiplying network for providing said reference wave and said last-mentioned direct current, said network comprising a bridge circuit having a pair of adjacent ratio arms each comprising a condenser and a. second pair of adjacent ratio erms each comprising a rectifying element and an inductance coil, an alternating cur rent input circuit for'applying across one arm of said first, pair of ratio arms and one arm of said second pair of ratio arms in series a voltage to be rectified and multiplied in frequency, a direct current output circuit for the rectified voltage connected across said condensers in series for supplying direct current to said apparatus, an alternating current output circuit including a portion of, said control means coupled to said coils for. derivingv therefrom an alternating current wave of a frequency which is a harmonic of thefrequency of said applied voltage, and means forrenderingsaid alternating current output circuit. selective to. said harmonic frequency.

.3. A- wave translating system comprising a source of alternatingcurrent of given frequency, means for producing therefrom a signal current of'twice said given frequency having phase reversals; rectifying means, for rectifying said signalcurrent, a direct current load device for operation bythe rectified current from said rectifying means in accordance with the phase of said signal current, amplifying means connected in tandem with said rectifying means between said source and said load device, and a voltage doubling rectifier and harmoni producer connected tosaid source and supplying to said amplifying. means: rectified current for energizing said amplifying means and supplying to said rectifying means alternating current of twice said given frequency for controlling the transmission efficiency of said rectifying means.

4. A wave translating system comprising a source of alternating current of given frequency, means for producing therefrom a signal current of twice said given frequency having phase reversals, a space discharge amplifying device having an anode, a cathode and a discharge control grid for amplifying said signal current, four twoterminal rectifying devices connected in series forming a closed circuit and poled in the same direction in the closed circuit, means comprising a resistance connecting said anode to the junction point of a pair of said rectifying devices, means comprising a resistance connecting said anode to the junction point of the other pair of said rectifying devices, a coil connected from one junction point between said pairs to the other junction point between said pairs, a connection between said cathode and the midpoint of said coil, a balanced amplifier including two space discharge amplifying devices each having an anode, electron emitting means and a discharge control grid, 9, low-pass filter connecting said first-mentioned junction point and said mid point with said control grid and electron emitting means of one of said amplifying devices of said balanced amplifier. a low-pass filter connecting said second-mentioned junction point and said mid-point with said control grid and electron emitting means of the other of said amplifying devices of said balanced amplifier, a circuit connected across said source comprising two parallel branches, one of said branches having in series a condenser, a. rectifier poled to transmit positive half-cycles of current of said source, and an inductance, and said other branch having in series a condenser, a rectifier poled to transmit negative half-cycles of current of said source, and an inductance, said inductanccs being so coupled to said coil that they respectively alternately produce like inductive effects on said coil, a circuit connected across said condensers in series for supplying space current for said firstmentioned amplifying device, and a condenser connected across said coil for tuning said coil to a frequency twice that of said source.

5. A system comprising control means controlled in accordance with phase relations between an alternating current signal wave of reversible polarity and a reference wave, and a direct current load device connected to said control means for operation in opposite senses according to the polarity of the alternating current signal wave, said control means comprising a transformer having a primary winding and a secondary winding, a path connected across said secondary winding including a pair of rectifying devices in series poled in the same direction in said path, and a second path connected across said primary winding including a pair of rectifying elements poled in the same direction in said second path, said system further comprising a source for supplying said signal wave connecting a point of said secondary winding intermediate its ends with a point of said first-mentioned path lying between said devices, and means for providing said reference wave including said transformer and a source of voltage of half the frequency of the signal wave connecting a point of said primary winding intermediate its ends with a point of said second path lying between said elements.

6. A wave translating system comprising a source of alternating current having phase reversals, a direct current responsive load device, a path for connecting said source to said device, a source of reference current of the frequency of said alternating current, and a circuit across said path responsive to said reference current to increase the impedance of said circuit to said alternating current during alternate half-cycles only of said reference current regardless of the phase relation of said alternating and reference currents, said circuit comprising two parallel branches each including a rectifying element, said rectifying elements being poled in the same direction in the series loop circuit constituted by said branches.

7. A wave translating system comprising a source of alternating signal current having phase reversals, means for supplying a reference wave of the frequency of said alternating current without phase reversals, two switching devices connected to said source and comprising four rectifying devices in series in a circuit with the rectifying devices poled in the same direction in the series circuit, a receiving circuit connected to said switching devices for receiving energy of said source under control of said switching devices, and means so applying said reference Wave to said switching devices that when the signal Wave has one phase one of said switching devices transmits from said source to said receiving circuit positive half-cycles of the signal current more readily than the intervening negative halfcycles and the other switching device transmits from said source to said receiving circuit said intervening negative half-cycles of the signal current more readily than said positive halfcycles and when the signal current has the opposite phase said one switching device transmits from said source to said receiving circuit negative half-cycles of the signal current more readily than the intervening positive half-cycles and said other switching device transmits from said source to said receiving circuit the intervening positive half-cycles of the signal current more readily than the negative half -cycles.

8. A wave translating system comprising a source of alternating signal current having phase reversals, a direct current responsive load device, a path for connecting said source to said device, a source of reference current of the frequency of said signal current, and a network shunted across said path having two parallel branches and including said source of reference current, each of said branches comprising a two-terminal rectifying element, said rectifying elements being poled in the same direction in the series loop circuit constituted by said branches, said source of reference current and said rectifying elements being all three in series.

RAYMOND W. KETCHLEDGE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,323,885 Wills July 13, 1943 1,559,642 Nyquist Nov. 3, 1925 1,992,908 Cockcroft et a1 Feb. 26, 1935 2,022,968 May Dec. 3, 1935 2,106,342 Doba Jan. 25, 1938

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