US2051503A - High frequency transmitting circuit - Google Patents
High frequency transmitting circuit Download PDFInfo
- Publication number
- US2051503A US2051503A US618607A US61860732A US2051503A US 2051503 A US2051503 A US 2051503A US 618607 A US618607 A US 618607A US 61860732 A US61860732 A US 61860732A US 2051503 A US2051503 A US 2051503A
- Authority
- US
- United States
- Prior art keywords
- coil
- coupling
- antenna
- transmission line
- circuit
- 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
Links
- 230000005540 biological transmission Effects 0.000 description 60
- 238000010168 coupling process Methods 0.000 description 50
- 238000005859 coupling reaction Methods 0.000 description 50
- 230000008878 coupling Effects 0.000 description 49
- 230000001939 inductive effect Effects 0.000 description 5
- 230000000903 blocking effect Effects 0.000 description 4
- 238000004804 winding Methods 0.000 description 4
- 239000004020 conductor Substances 0.000 description 3
- 230000003071 parasitic effect Effects 0.000 description 3
- 230000005855 radiation Effects 0.000 description 3
- 230000008030 elimination Effects 0.000 description 2
- 238000003379 elimination reaction Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H2/00—Networks using elements or techniques not provided for in groups H03H3/00 - H03H21/00
- H03H2/005—Coupling circuits between transmission lines or antennas and transmitters, receivers or amplifiers
- H03H2/006—Transmitter or amplifier output circuits
Definitions
- This invention concerns an improved coupling arrangement for coupling the output of a radio transmitter to a utilization circuit, such as a transmission line or an antenna system.
- Radio transmitters are frequently provided with two or more antenna systems for enabling the transmission of signals eiciently on more than one wave length. It is customary in transmitters which are adapted to operate on two or more frequencies to use a transmission line and antenna for each frequency and to provide individual variable arrangements for adjusting the coupling of each line.
- inductive coupling has been avoided in such systems due to the great diiiiculty which has been experienced in combining more than one inductive coupling coil to the single output of the transmitter.
- each of the transmission lines is adapted to function most eiiiciently on a frequency which differs greatly from those utilized by the other transmission lines, it has been found that a common coupling coil which is correct for only one particular frequency and not correct for other frequencies, does not lend itself readily to the emcient design of multi-frequency radio transmitters. For these reasons, it has been the practice in the past to use conductive coupling. Conductive coupling, however, has certain disadvantages, such as causing the transmission line and antenna to radiate second harmonic and push-push parasitic frequencies. These parasitic frequencies occur because the attached transmission line supplies a circuit in addition to the regular oscillating circuit.
- variable reactance circuits for adjusting the couplings of the individual transmission lines and for efficiently eliminating second harmonic energy in the lines and antenna systems.
- Figure 1 illustrates a single inductance coil coupling arrangement in accordance with the present invention which is adapted to selectively connect one of a plurality of transmission lines to the output circuit of a radio transmitting system;
- Figure 2 illustrates a modification of the circuit of Figure 1.
- Figures 3, 4 and 5 illustrate preferred embodiments of the present invention.
- 'Ihese include impedance changing circuits for the elimination of undesirable second harmonic energy from the transmission lines and antenna systems.
- Figure 6 illustrates a further embodiment for 54.:
- Figures 7 and 8 illustrate the present invention as applied to a single frequency transmitter or power amplifier stage utilizing only one antenna.
- FIG. 1 there is shown a multifrequency radio transmittingV system which is adapted to transmit signals on either of tWo frequencies over antenna'systems I and 2.
- radio transmitter is indicated diagrammatically l5 in box-I and may comprise a conventional type of push-pull power amplifier stage with which there is associated an output coil or tank circuit 2. Since the transmitting circuit forms no part of the present invention and is of a type that is 20;,A
- a single coil 3 is adapted to inductively couple tank circuit 2 to any one of the antenna systems l and 2 through switch 4.
- kConnected to the center point 25; of coil 3 is a high resistance element 5 which also connects with the plate supply lead as shown in the drawings. The purpose'of this resistancewill be described later.
- switching mechanism 4 tothe antenna systems are a plurality of blocking condensers 6, 6 of negligible impedance to the high frequency currents, which prevent direct current from the positive source of plate supply from entering the 35 antenna circuits proper.
- High frequency radio energy is fed from'tank coil 2 by means of the electromagnetic coupling to coil 3, through switch 4 to one-of the transmission line'sl'l andl 8. This switch may be thrown either up or down to select the desired transmission line and antenna system.
- adjustable impedance coils tand I0 are provided in transmission line 8 to ⁇ reduce the coupling and to cause the line totake less power.
- Resistor element 5 is arranged to maintain coupling coil 3 Vat the direct currentV plate potential a to prevent arcing from vthe plate tank coil V2 to the ⁇ coupling coil 3;Y Yarcondition which 'would 10 Y plingzzto any desired'degree.
- Figure 2 shows an arrangement wherein a con- 'denser Il, preferably variable, is utilized across transmission Aline Il and coupiing icoi1fi ⁇ 3 for vadjusting the coupling.
- ,coupling Ycoil 3 is arranged to work into a lower impedance and :condenser I I :is-utilized toiincrease the counating undesirable fsecond harmonic energy in Y' the :transmission :line and antenna.
- denser 2 L' may'bejcalledian ⁇ impedanceichanging circuit, :ani-important. characteristic of which s'its ability when jproperly adjusted to present :to the coupling coil 3 the :desired impedance at'unity powenfactor; 11n other swords, the loadpresented tothe transmitterfat the ⁇ operating Yfrequency .is purely resistive.
- coupling coil .'iumay-:bemadeztor have any Yconvenient-'or desi-rable size and the correct degree of coupling mayV be'provided for each transmission line and antenna by proper adjustment of an impedance changing circuit (coils 9 and I0 and condense 2i) in each transmission line.
- an impedance changing circuit coil 9 and I0 and condense 2i
- Switching elements l5 are used for'grounding the idle antenna transmission line. It has been found that the Vharmonic radiation from Vthe transmitter is thus greatly reduced by grounding ⁇ in the power amplifier thatY transmission line' vwhich is notin use at the Vparticular time of 'Y transmission. Switches I5, I5, it should be noted, short circuiting switches and made to ground the transmission lines on the antenna vside of the ⁇ D. C. blocking condensers 6, -6..V These ground switches may ⁇ be connected to the frame of the transmitter or to any'point WhichrisV substantially ...at :ground potential.
- variable impedance coils 9 and'lU are' shown vconnected between balanced con-Y denser ⁇ c2il,:wh'rch connectedracross the transmission line, and the antenna, whereas in the other figures the ivariable impedance coils are shown between 4-couplingfcoil 3 rgai-id ⁇ the'ba1ancedY condenser '-Zl.. :Theformer'manner of connection is fdesirable'ioridecreasing the-'coupling between the antennaasystemsand the coupling coil,Y
- 'Ihe circuit shown consists loiltwo connectionsy eachhaving a length of fone-fourth of -thegfun'damental wave length extendingffrom-fground 'to points Vlli ⁇ and H on each 'of the twowires 1 respectively, which are the ⁇ :samedistance from'coil 8.
- monicifrequency maybe used insteadfof the one quarter lWave "length straight WiresV for eliminatingthe second harmonic energy.
- l'l'.f standing Waves exist cophasially on the transmission line,V points 'L6 and YIl Ashould be Alocated .at the high potential .points on thereected second harmonic wave for more effective elimination of the second Y in accordance with the present invention, adjust the coupling to the required degree.
- Figures 7 and 8 illustrate a modiiied form o the present invention as applied to a single frequency transmitter having one antenna system, or as applied to a multi-frequency transmitter having a power amplifier stage for each frequency and antenna.
- both power ampliiiers of a transmitter may be energized at different times from a single exciter circuit.
- Figure 'l shows the arrangement of the impedance changing circuit 9, 10, 21, for presenting a low impedance to the coupling coil 3. Such an arrangement is adapted to increase the coupling between the transmitter and the antenna system.
- Figure 8 shows the arrangement of the impedance changing circuit for presenting a high impedance to coupling coil 3. The latter coupling arrangement decreases the coupling between the transmitter and the antenna.
- a wireless transmitter adapted to operate on either of two or more frequencies having, in combination, an ampliiier stage, a transformer having a primary winding and a secondary winding, said primary winding comprising the output of said amplifier stage, a first two wire transmission line and a second two wire transmission line, condensers in each wire of said two transmission lines, switching mechanism for selectively connecting either one of said transmission lines to said secondary Winding of said transformer, and a balanced variable condenser arrangement connected across the wires of one of said transmission lines for adjusting the impedance thereof, the eiiective midpoint of said conde ser arrangement being grounded.
- a wireless transmitter adapted rto operate on either of two or more frequencies having, in combination, an ampliiier stage, a first two wire transmission line and a second two wire trans-v mission line, condensers in each wire of said two transmission lines, a single coil inductively coupled to the output of said ampliiier stage, switching mechanism for selectively connecting either one of said transmission lines to said single coil, and variable reactance means associated with one of said transmission lines for adjusting the coupling thereof, a connection from the mid-point of said inductively coupled single coil to ground, and another connection from the eiTective center point of said variable reactance means to ground.
- a wireless transmitter having, in combination, an amplifier stage, a iirst two wire transmission line, and a second two wire transmission line, condensers in each wire of said two transmission lines, a single coil inductively coupled to the output of said amplier stage, switching mechanism for selectively connecting either one of said transmission lines to said single coil, a variable condenser connected across the wires of one of said transmission lines for adjusting the coupling thereof, a connection from the mid-point of said inductively coupled single coil to ground, and another connection from the effective center point of said variable condenser to ground, said last connection including a variable inductance to tune out the capacitive impedance of said variable condenser for the second harmonic frequency of the fundamental working wave for which said one transmission line is tuned.
- a wireless transmitter including a power amplifier stage having an output circuit, a single coil inductively coupled to said output circuit, a connection including a capacity from the mid-point of said single coil to ground, a first antenna circuit and a seco-nd antenna circuit, means for selectively associating said single coil in operative relation with either of said two antennas, condensers serially connected in the lines of said first and second antenna circuits, and variable reactance means in one of said antenna circuits for adjusting the coupling of said one circuit to said single coil.
- a wireless transmitter including a power amplifier stage having an output circuit comprising a coil whose mid-point is capacitively connected to ground, another coil inductively coupled to said rst coil and a capacitive connection from the mid-point of said second coil to ground, a first transmission line and a second transmission line, switching mechanism for selectively connecting said second coil with either one of said two transmission lines, and variable reactance means in one of said transmission lines for adjusting the coupling of said one transmission line to said second coil.
- a wireless transmission system as defined in claim 5 including a resistor connected between the mid-points of said two coils.
- a radio frequency transmitter having, in combination, an output circuit including a iirst inductance coil, a plurality of transmission line systems adapted to operate on different frequencies, a second coil inductively coupled to said inductance in the output circuit, switching mechanism for selectively connecting said second coil to any one of said transmission line systems, and means for maintaining the mid points of both coils at substantially the same direct current potential.
- a radio frequency transmitter having, in combination, an output circuit including an inductance, a two wire transmission line, an antenna, a single coil inductively coupled to said inductance in said output circuit and connected to one end of said line, the other end of which is connected to said antenna, adjustable coupling means comprising a variable reactance coil in each wire of said line, a balanced variable condenser across said line, and a connection from the middle of said balanced condenser to ground.
- a transmitter as defined in claim 8 including a variable reactance coil in said connection for tuning the capacity of said condenser.
- a radio frequency transmitter having an output circuit, a coupling coil inductively related to said output circuit, an antenna having a two conductor transmission line connecting said antenna with said coupling coil, an impedance changing circuit having an inductive reactance coil connecting one of said transmission line conductors to one terminal of said coupling coil, a second inductive reactance coil connecting the second transmission line conductor to the other terminal of said coupling coil, and a capacitive reactance condenser having a central element connected to ground through a ductorsl said reactance Ycoils ⁇ and condenser of said impedance'changing circuit beingw'capable of Y arrangement and'adjustment to transformat-the operating frequency the transmission line-iltmrned- Y ance in such manneras topr-esent to the-coupling coil and transmitter output circuit a load ofpure resistance and ⁇ of optimum valuerlfnatving ⁇ minimum harmonicradiation.'V Y
- a wireless transmitter including a power amplifier stage having an output circuit, a single .colrinductively coupled to said output circuit, azrst antenna circuit and a seceither--ofjsaid tworrantennas, condensers serially Vconnected in the lines of said'rflrst and second an'-,
- variable reactance means in one of said antenna circuits for adjusting theVV coupling of said one circuit to said single coil.
Landscapes
- Transmitters (AREA)
Description
* 2 Sheets-Sheet l Aug. 18, 1936. G. L. ussELMAN HIGH FREQUENCY TRANSMITTING" CIRCUIT' Filed June 22, 1932 Ildfla. lian- BY /g ATTORNEY Auf# 18| l936- G. L. ussELMAN l V 2,051,503
HIGH FREQUENCY TRANSMITTING CIRCUIT milf TRA//sM/rfm 172g. a Y
\f INVEN'TOR TMW/7750 GEORGE L. ussELMAN y n f BY ATTORNEY Patented Aug. 18, 1936 HIGH FREQUENCY TRANSMITTING CIRC UIT
George L. Usselman, Port Jefferson, N. Y., assignor to Radio Corporation of America, a corporation of Delaware Application June 22, 1932, Serial No. 618,607
11 Claims.
This invention concerns an improved coupling arrangement for coupling the output of a radio transmitter to a utilization circuit, such as a transmission line or an antenna system.
Radio transmitters are frequently provided with two or more antenna systems for enabling the transmission of signals eiciently on more than one wave length. It is customary in transmitters which are adapted to operate on two or more frequencies to use a transmission line and antenna for each frequency and to provide individual variable arrangements for adjusting the coupling of each line. Heretofore, inductive coupling has been avoided in such systems due to the great diiiiculty which has been experienced in combining more than one inductive coupling coil to the single output of the transmitter. Since each of the transmission lines is adapted to function most eiiiciently on a frequency which differs greatly from those utilized by the other transmission lines, it has been found that a common coupling coil which is correct for only one particular frequency and not correct for other frequencies, does not lend itself readily to the emcient design of multi-frequency radio transmitters. For these reasons, it has been the practice in the past to use conductive coupling. Conductive coupling, however, has certain disadvantages, such as causing the transmission line and antenna to radiate second harmonic and push-push parasitic frequencies. These parasitic frequencies occur because the attached transmission line supplies a circuit in addition to the regular oscillating circuit.
In accordance with the present invention, the foregoing disadvantages are entirely overcome by the provision of a single inductance coil coupling arrangement for all frequencies and all antennae.
Several features of the present invention reside in the variable reactance circuits for adjusting the couplings of the individual transmission lines and for efficiently eliminating second harmonic energy in the lines and antenna systems.
The invention is described more in detail in the following description accompanied by drawings, in which Figure 1 illustrates a single inductance coil coupling arrangement in accordance with the present invention which is adapted to selectively connect one of a plurality of transmission lines to the output circuit of a radio transmitting system; and
Figure 2 illustrates a modification of the circuit of Figure 1.
Figures 3, 4 and 5 illustrate preferred embodiments of the present invention. 'Ihese include impedance changing circuits for the elimination of undesirable second harmonic energy from the transmission lines and antenna systems.
Figure 6 illustrates a further embodiment for 54.:
eliminating undesirable second harmonic energy.
Figures 7 and 8 'illustrate the present invention as applied to a single frequency transmitter or power amplifier stage utilizing only one antenna.
Referring to Figure 1, there is shown a multifrequency radio transmittingV system which is adapted to transmit signals on either of tWo frequencies over antenna'systems I and 2. The
radio transmitter is indicated diagrammatically l5 in box-I and may comprise a conventional type of push-pull power amplifier stage with which there is associated an output coil or tank circuit 2. Since the transmitting circuit forms no part of the present invention and is of a type that is 20;,A
well known in the art, no detailed descriptionof the transmitter will begiven herein. A single coil 3 is adapted to inductively couple tank circuit 2 to any one of the antenna systems l and 2 through switch 4. kConnected to the center point 25; of coil 3 is a high resistance element 5 which also connects with the plate supply lead as shown in the drawings. The purpose'of this resistancewill be described later. Serially connected in the transmission lines Tand 8 'andfextending from 30:
switching mechanism 4 tothe antenna systems are a plurality of blocking condensers 6, 6 of negligible impedance to the high frequency currents, which prevent direct current from the positive source of plate supply from entering the 35 antenna circuits proper.
High frequency radio energy is fed from'tank coil 2 by means of the electromagnetic coupling to coil 3, through switch 4 to one-of the transmission line'sl'l andl 8. This switch may be thrown either up or down to select the desired transmission line and antenna system.
For effecting proper coupling for all transmission lines and antennae at their operating frequenciescoupling coil 3 is 'adjusted tov give correct coupling for that transmission line and antenna which takes the most power on a particular frequency and, consequently, requires the closest coupling. In most cases, this amount ofcoupling would be too much forgcorrect operation of the rsystem on other frequencies over other transmission lines and antennae. To obviate this diiiculty, adjustable impedance coils tand I0 are provided in transmission line 8 to` reduce the coupling and to cause the line totake less power.
These impedance coils are then'adjusted to effect Y the desired degree of coupling. In thisV manner,
the advantages of inductive coupling are obtained by the use of only'a single coupling coil for a plurality of transmission lines and antennasystems.
Resistor element 5 is arranged to maintain coupling coil 3 Vat the direct currentV plate potential a to prevent arcing from vthe plate tank coil V2 to the` coupling coil 3;Y Yarcondition which 'would 10 Y plingzzto any desired'degree.
' InFigui-.e QSiIthere is shown 'an arrangement Ywhich hastbeen usedtofgood 'advantage in'elimi-V otherwise occur due to leakage across the transmission line blocking Vcondens'ers 6, 6.V If it were Anot for this connection toV the platesuppiy such arcing would be recurrentY as the charges on the, 1 Y 3 Y coil leak orf through the condensers, 6 and tend to cause the coil to assumejaggroun'd potential.
Figure 2 shows an arrangement wherein a con- 'denser Il, preferably variable, is utilized across transmission Aline Il and coupiing icoi1fi`3 for vadjusting the coupling. In this circuit, ,coupling Ycoil 3 is arranged to work into a lower impedance and :condenser I I :is-utilized toiincrease the counating undesirable fsecond harmonic energy in Y' the :transmission :line and antenna. Tori-accomcondenser. 21| iisccnnectedftorgroimd:at its center pointiathrongh lead -'i'2. @It-should be notedtthat vso this connection does not affect the fundamental energy inthe:.-lineA which'operates push-pull, that is, inzphase opposition,whereas:all :even harmonic energy; noticeably the second harmonic, will be grounded ,rbecause fci'the"push-.push vor 'cophasal Y inductance ifmaylbe utilized in ythe-connection i2' to tune out the` capacitive impedance-of :con-V denser. 2.I.;for the fsecond harmonic frequencyV so 45.v 1 V,pointof coupling-'coil Vwthrough .la :large capacity n efiectl-onithetransmis'sion line. If desired, an
ast'o make the eiectivesimpedance 'to ground.' for 40: the 'second harmonic-energy very low. Y, In thisV way;:practically;faillithe second harmonic -energy present in the transmission line isaby-passed Vto ground. Y .f
` Another lmethod `roi' .reducing 'the Yundesirable second harmonicfenergyzis toground the center blocking condenser I4,`fas"shown"in'1igure 3,of the drawings.V This condenser should yhave asuncientlyihigh value towwithstand the plate-voltage 0f .the stage toy which coil"-3.is coupled. n Y .llfnfligures4;iand.5 are-:shown the-,preferred--arf Yrangements embodying "the principles -of the present invention. 'I'hese embodiments utilize an improved coupling arrangementL comprising 4both `the coilsv9 and @wand the balancedv or split capacity type condenserY 2|` `to eiect'fthe desired changev in transmission line :impedance facing Vcoupling `coili. `Goils '9 and vI-ll, Vtogether with :con-
denser 2 L' may'bejcalledian `impedanceichanging circuit, :ani-important. characteristic of which s'its ability when jproperly adjusted to present :to the coupling coil 3 the :desired impedance at'unity powenfactor; 11n other swords, the loadpresented tothe transmitterfat the `operating Yfrequency .is purely resistive. The adjustment .of the ,couplingarrangementshown in :Figures-4 and 5.is
somewhat'diierent from :thatzdescri-bedifor Figures -1,. 2 -and 3. The/.coil 3 '.intFigures 4 vand A5 may lbeconstructed :to :provide kcorrect coupling for-either-.onewof thegtransmission vlines and an- 'tennae` r impedance changing circuits (coils 9 fand Iilandscondenserlfl may befa'dusted'toV provide correct cnupling'for' the remaining transmission :lines land antennae. Again, coupling coil .'iumay-:bemadeztorhave any Yconvenient-'or desi-rable size and the correct degree of coupling mayV be'provided for each transmission line and antenna by proper adjustment of an impedance changing circuit (coils 9 and I0 and condense 2i) in each transmission line. Y
Switching elements l5 are used for'grounding the idle antenna transmission line. It has been found that the Vharmonic radiation from Vthe transmitter is thus greatly reduced by grounding `in the power amplifier thatY transmission line' vwhich is notin use at the Vparticular time of 'Y transmission. Switches I5, I5, it should be noted, short circuiting switches and made to ground the transmission lines on the antenna vside of the `D. C. blocking condensers 6, -6..V These ground switches may `be connected to the frame of the transmitter or to any'point WhichrisV substantially ...at :ground potential.
In Figure 5 variable impedance coils 9 and'lU are' shown vconnected between balanced con-Y denser`c2il,:wh'rch connectedracross the transmission line, and the antenna, whereas in the other figures the ivariable impedance coils are shown between 4-couplingfcoil 3 rgai-id`\the'ba1ancedY condenser '-Zl.. :Theformer'manner of connection is fdesirable'ioridecreasing the-'coupling between the antennaasystemsand the coupling coil,Y
wl'ieneastheatter imannerisdesirable for 'increasing ztiierfcoupling. i
It should .be fnotedthatigures 4 and v5 also innlu'de the lconnection-015 `fthe middle element of variable condenser1-l to'sground Vthrough the Y varablelinduwctanceccoil :i3 and -the v connection ofthe midpoint'of couplingffcoili3 to groundior highirequencies through the kbit-passv condenser lf4,.forthe :purpose of reducing harmonic radiation; -Y Y Figure 6 :illustratesLaiurther arrangement rfor eliminating secondharmonic lenergy in the transmission `Eline andantenna. 'Ihe circuit shown consists loiltwo connectionsy eachhaving a length of fone-fourth of -thegfun'damental wave length extendingffrom-fground 'to points Vlli `and H on each 'of the twowires 1 respectively, which are the `:samedistance from'coil 8. These'connections are one-quarter wave-'length long for -the fundamentall frequency and thereforel oier `a high impedance-to ycurrents ofV this frequency, but are onehazifwaive flengthV long for the second harmon-ic irequency'andfpresentvery ilo-w impedance to'rground `for currents lofrthis latter frequency,v thus `Ieliminating energy .of this v-harmonic frei Y quency. iromithe' transmission :lines and antennae.
If desired, coils which are effectively a quarter wave length Vlong'for the'fun'damental frequency cria 'half Wave length v-long'ffor the second har-.l
monicifrequency maybe used insteadfof the one quarter lWave "length straight WiresV for eliminatingthe second harmonic energy. l'l'.f standing Waves exist cophasially on the transmission line,V points 'L6 and YIl Ashould be Alocated .at the high potential .points on thereected second harmonic wave for more effective elimination of the second Y in accordance with the present invention, adjust the coupling to the required degree. Y
Figures 7 and 8 illustrate a modiiied form o the present invention as applied to a single frequency transmitter having one antenna system, or as applied to a multi-frequency transmitter having a power amplifier stage for each frequency and antenna. In the iigures shown, both power ampliiiers of a transmitter, of course, may be energized at different times from a single exciter circuit. Figure 'l shows the arrangement of the impedance changing circuit 9, 10, 21, for presenting a low impedance to the coupling coil 3. Such an arrangement is adapted to increase the coupling between the transmitter and the antenna system. Figure 8 shows the arrangement of the impedance changing circuit for presenting a high impedance to coupling coil 3. The latter coupling arrangement decreases the coupling between the transmitter and the antenna.
'17ha coupling arrangements shown in Figures 7 and 8 are desirable for reducing harmonic radiation and for stopping parasitic oscillations and also for enabling the use in the transmitter of a rigidly fixed coupling coil without fractional turns. This also allows the use of a convenient or desirable size of coupling coil regardless of coupling since correct coupling can be obtained by proper adjustment of the impedance changing circuit (coils 9 and l0 and condenser 2l) I claim:
l. A wireless transmitter adapted to operate on either of two or more frequencies having, in combination, an ampliiier stage, a transformer having a primary winding and a secondary winding, said primary winding comprising the output of said amplifier stage, a first two wire transmission line and a second two wire transmission line, condensers in each wire of said two transmission lines, switching mechanism for selectively connecting either one of said transmission lines to said secondary Winding of said transformer, and a balanced variable condenser arrangement connected across the wires of one of said transmission lines for adjusting the impedance thereof, the eiiective midpoint of said conde ser arrangement being grounded.
2. A wireless transmitter adapted rto operate on either of two or more frequencies having, in combination, an ampliiier stage, a first two wire transmission line and a second two wire trans-v mission line, condensers in each wire of said two transmission lines, a single coil inductively coupled to the output of said ampliiier stage, switching mechanism for selectively connecting either one of said transmission lines to said single coil, and variable reactance means associated with one of said transmission lines for adjusting the coupling thereof, a connection from the mid-point of said inductively coupled single coil to ground, and another connection from the eiTective center point of said variable reactance means to ground.
3. A wireless transmitter having, in combination, an amplifier stage, a iirst two wire transmission line, and a second two wire transmission line, condensers in each wire of said two transmission lines, a single coil inductively coupled to the output of said amplier stage, switching mechanism for selectively connecting either one of said transmission lines to said single coil, a variable condenser connected across the wires of one of said transmission lines for adjusting the coupling thereof, a connection from the mid-point of said inductively coupled single coil to ground, and another connection from the effective center point of said variable condenser to ground, said last connection including a variable inductance to tune out the capacitive impedance of said variable condenser for the second harmonic frequency of the fundamental working wave for which said one transmission line is tuned.
4. In combination, a wireless transmitter including a power amplifier stage having an output circuit, a single coil inductively coupled to said output circuit, a connection including a capacity from the mid-point of said single coil to ground, a first antenna circuit and a seco-nd antenna circuit, means for selectively associating said single coil in operative relation with either of said two antennas, condensers serially connected in the lines of said first and second antenna circuits, and variable reactance means in one of said antenna circuits for adjusting the coupling of said one circuit to said single coil.
5. In combination, a wireless transmitter including a power amplifier stage having an output circuit comprising a coil whose mid-point is capacitively connected to ground, another coil inductively coupled to said rst coil and a capacitive connection from the mid-point of said second coil to ground, a first transmission line and a second transmission line, switching mechanism for selectively connecting said second coil with either one of said two transmission lines, and variable reactance means in one of said transmission lines for adjusting the coupling of said one transmission line to said second coil.
6. A wireless transmission system as defined in claim 5 including a resistor connected between the mid-points of said two coils.
7. A radio frequency transmitter having, in combination, an output circuit including a iirst inductance coil, a plurality of transmission line systems adapted to operate on different frequencies, a second coil inductively coupled to said inductance in the output circuit, switching mechanism for selectively connecting said second coil to any one of said transmission line systems, and means for maintaining the mid points of both coils at substantially the same direct current potential.
8. A radio frequency transmitter having, in combination, an output circuit including an inductance, a two wire transmission line, an antenna, a single coil inductively coupled to said inductance in said output circuit and connected to one end of said line, the other end of which is connected to said antenna, adjustable coupling means comprising a variable reactance coil in each wire of said line, a balanced variable condenser across said line, and a connection from the middle of said balanced condenser to ground.
9. A transmitter as defined in claim 8 including a variable reactance coil in said connection for tuning the capacity of said condenser.
10. In combination, a radio frequency transmitter having an output circuit, a coupling coil inductively related to said output circuit, an antenna having a two conductor transmission line connecting said antenna with said coupling coil, an impedance changing circuit having an inductive reactance coil connecting one of said transmission line conductors to one terminal of said coupling coil, a second inductive reactance coil connecting the second transmission line conductor to the other terminal of said coupling coil, and a capacitive reactance condenser having a central element connected to ground through a ductorsl said reactance Ycoils `and condenser of said impedance'changing circuit beingw'capable of Y arrangement and'adjustment to transformat-the operating frequency the transmission line-iltmrned- Y ance in such manneras topr-esent to the-coupling coil and transmitter output circuit a load ofpure resistance and` of optimum valuerlfnatving `minimum harmonicradiation.'V Y
tenna circuits, and variable reactance means in one of said antenna circuits for adjusting theVV coupling of said one circuit to said single coil.
GEORGE YI... UssELMAN.
' ond antenna circuit, means for selectively asso- Y Vciating said single coilin operative relation with Y
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US618607A US2051503A (en) | 1932-06-22 | 1932-06-22 | High frequency transmitting circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US618607A US2051503A (en) | 1932-06-22 | 1932-06-22 | High frequency transmitting circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2051503A true US2051503A (en) | 1936-08-18 |
Family
ID=24478382
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US618607A Expired - Lifetime US2051503A (en) | 1932-06-22 | 1932-06-22 | High frequency transmitting circuit |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2051503A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2561871A (en) * | 1947-03-22 | 1951-07-24 | Rca Corp | High-power transmission line switch |
| US2925598A (en) * | 1954-07-16 | 1960-02-16 | Ralph R Williams | Antenna network employing a variable capacitance |
| US3335216A (en) * | 1965-01-05 | 1967-08-08 | Motorola Inc | Trap circuit for color receiver demodulators |
| US4433315A (en) * | 1981-11-24 | 1984-02-21 | General Electric Company | Tunable coupling network |
| WO1993020621A1 (en) * | 1992-04-02 | 1993-10-14 | Stanford Telecommunications, Inc. | Method and apparatus for intermodulation noise suppression in rf power amplifiers |
| US20050280597A1 (en) * | 2004-06-19 | 2005-12-22 | Samsung Electronics Co., Ltd. | Antenna module |
| US20180277960A1 (en) * | 2015-05-18 | 2018-09-27 | Cavendish Kinetics, Inc. | Method and apparatus of maintaining constant antenna resonant frequency and impedance match in the p |
| US20220377870A1 (en) * | 2020-11-20 | 2022-11-24 | Ulvac, Inc. | High-frequency power circuit, plasma treatment apparatus, and plasma treatment method |
-
1932
- 1932-06-22 US US618607A patent/US2051503A/en not_active Expired - Lifetime
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2561871A (en) * | 1947-03-22 | 1951-07-24 | Rca Corp | High-power transmission line switch |
| US2925598A (en) * | 1954-07-16 | 1960-02-16 | Ralph R Williams | Antenna network employing a variable capacitance |
| US3335216A (en) * | 1965-01-05 | 1967-08-08 | Motorola Inc | Trap circuit for color receiver demodulators |
| US4433315A (en) * | 1981-11-24 | 1984-02-21 | General Electric Company | Tunable coupling network |
| WO1993020621A1 (en) * | 1992-04-02 | 1993-10-14 | Stanford Telecommunications, Inc. | Method and apparatus for intermodulation noise suppression in rf power amplifiers |
| US5930688A (en) * | 1992-04-02 | 1999-07-27 | Stanford Telecommunications, Inc. | Method and apparatus for intermodulation noise suppression in RF power amplifiers |
| US20050280597A1 (en) * | 2004-06-19 | 2005-12-22 | Samsung Electronics Co., Ltd. | Antenna module |
| US7154448B2 (en) * | 2004-06-19 | 2006-12-26 | Samsung Electronics Co., Ltd. | Antenna module |
| US20180277960A1 (en) * | 2015-05-18 | 2018-09-27 | Cavendish Kinetics, Inc. | Method and apparatus of maintaining constant antenna resonant frequency and impedance match in the p |
| US10418717B2 (en) * | 2015-05-18 | 2019-09-17 | Cavendish Kinetics, Inc. | Method and apparatus of maintaining constant antenna resonant frequency and impedance match in the presence of environmental changes and head/hand effect using variable reactance antenna aperture tuners |
| US20220377870A1 (en) * | 2020-11-20 | 2022-11-24 | Ulvac, Inc. | High-frequency power circuit, plasma treatment apparatus, and plasma treatment method |
| US11665809B2 (en) * | 2020-11-20 | 2023-05-30 | Ulvac, Inc. | High-frequency power circuit, plasma treatment apparatus, and plasma treatment method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US2128400A (en) | Transmission line system | |
| US2051503A (en) | High frequency transmitting circuit | |
| US2184771A (en) | Antenna coupling means | |
| US2631241A (en) | Tuning device for high-frequency electrical energy | |
| US2174963A (en) | Electrical wave resonant line filter | |
| US2692919A (en) | Stabilized driven grounded grid amplifier circuits | |
| US2084740A (en) | Filter circuit | |
| US2816222A (en) | Mixing circuit for superheterodyne receivers | |
| US2594167A (en) | Ultrahigh-frequency bridge circuits | |
| US2310323A (en) | Antenna coupling and tuning system for communication or broadcast receivers | |
| US2520811A (en) | Power line antenna | |
| US3049682A (en) | Constant bandwidth coupling system | |
| US2150562A (en) | Multiple wave band receiver | |
| US2479537A (en) | Detector-oscillator circuit for ultra high frequency receivers | |
| US2912656A (en) | Constant bandwidth coupling system | |
| US2031103A (en) | Ultra short wave receiver | |
| GB514778A (en) | Improvements in radio signalling systems | |
| US2124212A (en) | Radio receiver | |
| US2074896A (en) | Antenna system for multiband radio receivers | |
| US2038294A (en) | Coupling system | |
| US3162809A (en) | Antenna tuner circuit for radio transceiver | |
| US2093416A (en) | Feedback circuits | |
| US2250370A (en) | All-wave loop receiver | |
| US2027986A (en) | Superheterodyne receiver | |
| US1725721A (en) | Method and means for combining frequencies |