US2474978A - Circuit arrangement for use with widely separated frequency bands - Google Patents

Circuit arrangement for use with widely separated frequency bands Download PDF

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Publication number
US2474978A
US2474978A US611378A US61137845A US2474978A US 2474978 A US2474978 A US 2474978A US 611378 A US611378 A US 611378A US 61137845 A US61137845 A US 61137845A US 2474978 A US2474978 A US 2474978A
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United States
Prior art keywords
valve
frequency
frequencies
switch
circuit
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Expired - Lifetime
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US611378A
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English (en)
Inventor
Holland John Douglas
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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
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/08—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance
    • H03B5/10—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being vacuum tube
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
    • H03D7/06—Transference of modulation from one carrier to another, e.g. frequency-changing by means of discharge tubes having more than two electrodes
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/42—Modifications of amplifiers to extend the bandwidth
    • H03F1/48—Modifications of amplifiers to extend the bandwidth of aperiodic amplifiers
    • H03F1/50—Modifications of amplifiers to extend the bandwidth of aperiodic amplifiers with tubes only
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/46—Reflex amplifiers
    • H03F3/48—Reflex amplifiers with tubes only
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/66—Amplifiers simultaneously generating oscillations of one frequency and amplifying signals of another frequency
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/16—Circuits
    • H04B1/26—Circuits for superheterodyne receivers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J1/00—Frequency-division multiplex systems

Definitions

  • the present invention relates to thermionic valve circuits and particularly to circuits for translating or generating signals occupying two difi'erentbands of frequencies.
  • m Y w Fig. 3 shows aschematici-circnit diagram of atWc-path radio receiver according to the invention.
  • Fig. 4 shows amodification: of; partofFig. 3..
  • .Fig. 5 shows a radio receiver according to the invention providing twosepara-te signal channels;and'-" w Fig. 6 shows a. double-oscillator according to the invention.
  • the.-.screen. electrode. is not, essential. andv can be omitted, the minimum re.- quirement being that there. should be at least three grids between. the cathode and the anode. There may, of course-,bany number of grids in: excess of three the extra. grids-being suitably polarized.v
  • Fig. 1 shows diagrammatically. an arrange:- ment according to the invention.
  • a pentagrid valve l comprises: ascathode :2, three grids 4 and 5,.a screen grid electrode ,6 and an anodel.
  • The-cathode 2 is connected to the grounded negative terminal .8 of the high tension supply, the positiveterminal 9 of which is con-- nected: directly to the screen grid B and to elQQ- trodes 4- and'lathrough impedance elements Hiand ill-respectively.
  • control grids ,3 and :5 are connected to inputterminals Hand 13 re:- spectively,.and the anodes 4- and Tare connectedto output terminals l4: and: 15 through blocking, condensers l6 and ,lil', respectively.
  • a condenser 2 I serves. as a lay-pass condenser shunting .the high tension source;..-.. H
  • the impedance .elements 18 and I ⁇ ! represent input circuits reach carrying a separate channel ofi-signals.
  • I Thesignalinput voltages are represented bythe symbolsei and as in series with the elements -I8'and.l;9. .
  • the amplified or otherwise translated signals are obtained at the output terminals M andzla5 thecorresponding output voltages bein-glEi and E2. as indicated.
  • the impedance elements Hil and II accordingly represent any suitable tuned icirc-uitszor filters, or. the like, adapted. to suppress one of -theirequencies andto allow the other to pass. In order that this.
  • the impedance, elementa -the;-ztwov frequencies f1. and f2 should preferably be widely separated; for example, one should be not less than about double the other, and preferably also one frequency should not be a harmonic of the other. Where the signals comprise two bands of frequencies, then the lowest frequency of the upper band should preferably be at least double the highest frequency of the lower band.
  • the two triode portions of the valve I will usually have different mutual conductances (the upper portion having generally th higher value) and in order to minimise interference the associated circuits should preferably be arranged so that the gains of the two amplifiers do not differ by more than about 10 decibels.
  • the output circuit which operates at the lower frequency will usually have a higher dynamic impedance than that operating at the lower frequency, it is desirable to operate the triode portion 2, 3, 3, at the lower frequency so that by associating with it the high impedance output circuit the gains of the two amplifiers will tend to be equalized.
  • valve 1 If the two triode portions of the valve 1 are not operated simultaneously, then it is not important that the two frequencies f1 and f2 should be very widely separated, or that they should be harmonically unrelated, and a larger difference of gain for the two amplifiers can be allowed, since interference does not arise. In any case however, it is desirable that the valve should be so biassed that neither of the amplifiers are overloaded.
  • the signals applied at terminals l2 and I3 are independently amplified and are kept to separate circuits throughout.
  • the two corresponding channels may be used simultaneously or separately.
  • the arrangement is equivalent to two separate amplifiers each with its own valve, but the two valves are part of the same pentagrid valve.
  • the valve I may also be used as a double frequency changer. In this case the strap between the terminals 22 and 23 shown in the grid connection is removed and these terminals are connected to a suitable local carrier frequency oscillator (not shown).
  • the bias circuit 20 is chosen so that both sections of the valve I operate as modulators. Then if f is the local carrier frequency, side bands fo+f1 can be obtained from the anode 4 and sidebands fo-l-fz from the anode I.
  • the circuit elements It! and H could then comprise band filters each of which is adapted to select a corresponding side band and to supply it to terminal I 4 or [5. So long as the frequencies f1 and f2 are well separated, the band filters represented by the elements I ⁇ I and H need not be very selective.
  • the two channels may be provided with different local carrier frequencies by means of a simple switching arrangement, such as that shown in Fig. 2, in which the elements which are similar to corresponding elements of Fig. 1 are designated by the same numerals.
  • 24 and 25 represent the sources of the voltages er and 62 at frequencies f1 and f2.
  • a switch 26 connects the source 24 to the input terminal l2 in the position shown, and in the other positions it disconnects the source 24 and instead connects the source 25 to the input terminal 13.
  • a carrier frequency source 2! of voltage es and frequency is is connected by the switch 28 when in the position shown to the terminals 22 and 23 in series with the cathode 2. This will produce a side band f3+f1 at terminal 14 of voltage E3.
  • the switch 28 When the switch 28 is operated to the other position, it substitutes for the source 21 a source 29 of voltage at at frequency ii. If the two switches 26 and 28 are mechanically connected so as to be operated together, then a.
  • Fig. 2 can be either a modulator or a demodulator for either channel; and it could be a modulator for one channel and a demodulator for the other.
  • FIG. 2 In the remaining figures of the accompanying drawings three different types of circuit according to the invention are given as illustrations of the general principles described with reference to Figs. 1 and 2. These types are as follows:
  • Fig. 3 shows a circuit according to the invention suitable for a radio receiver adapted to cover a very wide range of frequencies, for example 15 to 26,000 kilocycles per second (kc. s.).
  • kc. s. kilocycles per second
  • two channels are provided in the receiver, in which intermediate frequencies of 40 and 560 kc. s. are respectively derived and amplified in the two corresponding portions of the valves.
  • the waves are received on an antenna 30 and are passed to the high frequency amplifiers and selective circuits 3
  • a switch 32 enables the output of 3
  • a carrier frequency oscillator 34 of adjustable frequency corresponds to the oscillator 21 of Fig. 1 and is connected to the cathode circuit of the valve 33 through a transformer 35. The usual bias network for this cathode is shown at 36.
  • Two tuned output transformers 3'! and 38 couple the two triode portions of the valve 33 to the corresponding triode portions of an amplifying pentagrid valve 39.
  • This amplifying valve has the usual cathode bias network 40, and also a coil 4
  • valve "I of Fig. 1 the tuned transformers 42 and oo xc tzo dieg. r nectivelyt i hei.e ements, wa U cf this.
  • figur tuned tra s q mexsfl and 42 operate as h n pa -filte s a d-.shomd' o'dec i n tenets.
  • a m 1 two anodes of the valve 39. are, each con: nected through the primary winding. of. the. cor:
  • v ;mates nding conne tions to. the valve-.33 are similar, except that. .two. normally closed a di hWc ecn-intermsed as shown. for. .Rutpo e .toh explained, later inconnection w thanother.embodim nt.otthcinvcntioncT ey ar not needed for theiemb diment now being deg1, n u d e m t edv, .p lous t flemtioned dete t r. c rcu t com ris s.
  • J smecessary. to 1 provide-lion stand-by: reqeptl ll- Q1 high, equate-y;amplifiers-rand:- selective circuitsadagtedior the range 2 tionc glearly the ropil;;A-L-.could.- alternatively be"- t thcatltainstormer 43 int-iwhichtcase the" A edloack will .be applied/to. the upper flofilfi ns ead? ,Q vliomthe zlowerntriode.
  • the carrier frequency oscillator 34 is as before, and is adapted for the range covered by the amplifier 3i.
  • a switch 15 allows the antenna 30 to be connected to either of the elements 31 or 14, and another switch 76, which may be coupled to 15 is provided for disconnecting the oscillator 34 when the antenna 30 is connected to the element 14.
  • the valve 33 should be biassed in such a manner that the lower triode portion operates as a simple amplifier for the stand-by range 488 to 515 kc. s., while the upper triode acts as a modulator for the high frequency range as before, and the oscillator 34 is set to produce a suitable intermediate frequency such as 1,000 kc. s., to which the transformers 38 and 43 will be tuned.
  • the transformers 31 and 42 will of course be tuned for the stand-by range. Selection by the double diode 44 for both ranges takes place as before.
  • the advantage of this arrangement is that the operator may set his apparatus to receive on some frequency in the high frequency range, and by simply operating the two switches 75 and 16 (Fig. 4) he may listen in at any time on the stand-by range without upsetting the normal adjustments of the apparatus for the high frequency range. It is to be noted that the switch 16 disconnects the oscillator 34 when the valve 33 is acting as an amplifier for the stand-by range.
  • FIG. 3 the switch 15 may be omitted and the antenna 39 may be permanently connected to both of the devices 3
  • Fig. 5 shows an example of a pentagrid valve arranged according to the invention to produce amplification in each of two entirely separate signal channels which may be used separately or simultaneously.
  • the valve 39 with its tuned transformers 37, 38, 42 and 43 is arranged practically in the same way as in Fig. 3 except that the feedback coil 4i and the automatic gain control arrangements are omitted.
  • the first channel comprises an antenna 11 connected to receiving circuits represented by the block i8 and including ferquency changing means supplying a first intermediate frequency to the tuned transformer 31.
  • This channel also comprises a detecting circuit 19 connected to the tuned transformer 42 and supplying the detected signals to the receiver 80.
  • the second channel comprises the antenna 8
  • the two intermediate frequencies (which should preferably be well separated, as already explained) are amplified, by the respective portions of the pentagrid 39 as previously described, and are separately detected and supplied to corresponding receivers.
  • the two signal channels so obtained are thus quite independent of one another.
  • Additional stages of amplification may be provided by other valves arranged in the same way as the valve 39.
  • circuits represented by the blocks I8, 19, 82 and 83 are not shown in detail, and they may be provided in any well known way.
  • the tuned transformers 31, 38, 42 and 43 represent only one possible form of selective circuits which may be used for keeping the two channels separate.
  • Various other types of tuned circuits could be used, or wave filters of various configurations. What is required is that the selective circuits used in one channel shall transmit the waves corresponding to that channel and shall exclude those corresponding to the other channel.
  • Fig. 6 shows an example of a double oscillator designed according to this principle.
  • the valve 85 is a pentagrid as before. is closed, the anode of the lower triode portion is coupled back to the control grid by means of the inductively coupled coils 81 and 88 which are tuned by the condenser 89, the circuit being completed by the relatively large blocking condenser 99 and by-pass condenser 9
  • the switch 92 is closed, the anode of the upper triode portion of the valve is coupled back to the control grid by means of the inductively coupled coils 93 and 94 which are tuned by the condenser 95, the circuit being completed by the blocking condenser 96.
  • the upper and lower control grids are connected to the cathode by the high resistances 9! and 98.
  • the high tension supply is intended to be connected to the terminals 99 and l 99 as indicated and the negative terminal I99 may be connected to ground.
  • the oscillator of Fig. 6 may be conveniently employed in combination with Fig. 3 for the reception of continuous wave telegraphy.
  • the output coils HM and H12 may be respectively connected to corresponding additional windings (not shown)
  • the switch 86 on the transformers 42 and 43 of Fig. 3. Assuming that the intermediate frequencies corresponding to the two continuous wave channels are 40 k. c. s. and 560 k. c. s. as before, then the lower and upper triodes in Fig. 6 may be tuned to oscillate at H and 561 k c. s. for example, giving a beat note of 1000 cycles with the above mentioned intermediate frequencies.
  • switches 86 and 92 may be mechanically coupled with the switch 3
  • Another switch (not shown) associated with the oscillator 34 may if desired be also mechanically coupled to the switch 3
  • the oscillator of Fig. 6 may be designed to produce any desired pair of frequencies.
  • An electric wave translating arrangement for a wide band of frequencies comprising a thermionic valve having a cathode, an anode, and at least three grid electrodes mounted in order therebetween, a source of signals of a wide band of frequencies, a switch connected to said source and having two contacts connected respectively to the first and third of said grid electrodes counting from said cathode, and two selective filter circuits connected respectively to the second of said grid electrodes and to said anode, the filter circuit connected to said second grid electrode being designed to pass the lower frequencies of said band of frequencies and to exclude the higher band, the filter circuit connected to said anode being designed to pass the higher frequencies of said band of frequencies and to exclude the 1ower band, whereby said switch is positioned to make contact with said first grid contact for said lower frequencies and with said third grid contact for said higher frequencies, said arrangement passing said broad band of frequencies.
  • each of said filter circuits comprises a band filter composed of a transformer having tuned primary and secondary windings, each of said filter circuits being designed to exclude frequencies passed by the other of said filters.
  • a translating device wherein said signal source and said switch are connected in series between said cathode and the one of said grids to which said switch is connected and which further comprises a source of a constant frequency connected in series with said cathode and said signal source for beating said constant frequency with said signals.
  • a translating device which further comprises a source of operating potential for said tube connected in series with said cathode and both said filter circuits, whereby said tube amplifies said signals.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
US611378A 1944-09-01 1945-08-18 Circuit arrangement for use with widely separated frequency bands Expired - Lifetime US2474978A (en)

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GB250786X 1944-09-01

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US (1) US2474978A (en(2012))
BE (1) BE477233A (en(2012))
CH (1) CH250786A (en(2012))
FR (1) FR939230A (en(2012))

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2541818A (en) * 1948-12-18 1951-02-13 Gen Electric Radio receiver
US2684402A (en) * 1949-12-31 1954-07-20 Stromberg Carlson Co Dual-purpose carrier-wave receiver
US2771548A (en) * 1952-07-08 1956-11-20 Polytechnic Res & Dev Co Inc Receiver tunable over v. h. f. and u. h. f. television bands
US3080532A (en) * 1960-01-14 1963-03-05 Collins Radio Co Voltage variable gain circuit with gate correction
US3420954A (en) * 1961-08-25 1969-01-07 Rca Corp Signal translating system

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1022275B (de) * 1953-11-14 1958-01-09 Siemens Elektrogeraete Gmbh Verfahren und Einrichtung zum Empfang von ueber getrennte modulierte Traegerwellen stereophonisch uebertragenen Schallsendungen

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2006969A (en) * 1932-07-24 1935-07-02 Telefunken Gmbh Amplifying device
US2058512A (en) * 1934-05-28 1936-10-27 Rca Corp Radio receiver
US2189317A (en) * 1938-08-31 1940-02-06 Rca Corp Diversity antenna system
US2201365A (en) * 1938-07-13 1940-05-21 Hazeltine Corp Duplex vacuum-tube repeater
US2257782A (en) * 1939-01-24 1941-10-07 Radio Patents Corp Amplifier
US2288486A (en) * 1940-04-01 1942-06-30 Hazeltine Corp Multiple-frequency oscillator

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2006969A (en) * 1932-07-24 1935-07-02 Telefunken Gmbh Amplifying device
US2058512A (en) * 1934-05-28 1936-10-27 Rca Corp Radio receiver
US2201365A (en) * 1938-07-13 1940-05-21 Hazeltine Corp Duplex vacuum-tube repeater
US2189317A (en) * 1938-08-31 1940-02-06 Rca Corp Diversity antenna system
US2257782A (en) * 1939-01-24 1941-10-07 Radio Patents Corp Amplifier
US2288486A (en) * 1940-04-01 1942-06-30 Hazeltine Corp Multiple-frequency oscillator

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2541818A (en) * 1948-12-18 1951-02-13 Gen Electric Radio receiver
US2684402A (en) * 1949-12-31 1954-07-20 Stromberg Carlson Co Dual-purpose carrier-wave receiver
US2771548A (en) * 1952-07-08 1956-11-20 Polytechnic Res & Dev Co Inc Receiver tunable over v. h. f. and u. h. f. television bands
US3080532A (en) * 1960-01-14 1963-03-05 Collins Radio Co Voltage variable gain circuit with gate correction
US3420954A (en) * 1961-08-25 1969-01-07 Rca Corp Signal translating system

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BE477233A (en(2012))
FR939230A (fr) 1948-11-08
CH250786A (de) 1947-09-15

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