US2064220A - Radio receiver - Google Patents

Radio receiver Download PDF

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Publication number
US2064220A
US2064220A US635370A US63537032A US2064220A US 2064220 A US2064220 A US 2064220A US 635370 A US635370 A US 635370A US 63537032 A US63537032 A US 63537032A US 2064220 A US2064220 A US 2064220A
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Prior art keywords
grid
tube
circuit
frequency
plate
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US635370A
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English (en)
Inventor
Rocard Yves
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Thales SA
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CSF Compagnie Generale de Telegraphie sans Fil SA
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    • 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
    • H03D7/10—Transference of modulation from one carrier to another, e.g. frequency-changing by means of discharge tubes having more than two electrodes the signals to be mixed being applied between different pairs of electrodes

Definitions

  • the present invention discloses a general principle, and improved methods, adapted to insure in the proper manner a change in frequency particularly by the aid of a radio modulator twin-grid tube without creating, or permitting the production of, stray waves whose interference with the wave of the new frequency, or with the component or constituent waves, would result in inconvenience that would manifest itself at the acoustic output end of the equipment in the form of fundamental noises, whistling, etc. Its chief application is in connection with the superheterodyne type of radio receiver set.
  • the efficiency of the methods here disclosed may be explained by, and is based upon, an observation made by the inventor according to which the curvature of the characteristic of the tubes which, in one stage of amplification, as is well known in the art, results in diaphony (or cross-talk), and an apparent growth in the depth of the modulation, will also cause, inside a tube intended and designed to insure a change in frequency, waves having a frequency close to that of the new frequency which is desired to be obtained; and these waves on passing into the succeeding amplifier produce upon final detection a heat of a relatively low and audible frequency.
  • a way adapted to diminish the whistling according to the present invention consists in causing the change in frequency by the aid of a distinct detector constituted by a variable mu tube.
  • a distinct detector constituted by a variable mu tube.
  • the structure of the variable mu tube has as its object an attenuation in the development (1) of the terms of cV eV resulting incross-talk, or diaphony, if the tube does amplifier work; but the same structure further has this effect that it reduces the terms of dV Vg which are responsible for the whistling of superheterodynes.
  • the use of a variable mu, screen grid type tube as the first detector in a superheterodyne set will thus be eflicient and suitable'fromthis viewpoint.
  • V comprises not only terms on sin wl 18 sin wzt, 'y sin w3l'1, etc.,
  • n sin wt due to the heterodyne current which, by virtue of interelectrode capacitance returns to the impedance acting upon the control grid.
  • CoVg will also produce the mean frequency as a result of simple detection as in a standard. detector with separate heterodyne.
  • the invention discloses the simultaneous use of a radio frequency filter designed to lessen as far as feasible the stray compared with the signal, and an arrangement acting upon the control grid by the output of this filter, though in combination with coupling means making the regulation of the radio frequency circuits practically independent of the regulation of the heterodyne.
  • the invention suggests the construction and utilization of a twin-grid tube of a special kind where the control action exercised by the control grid is of what has become known as the variable mu kind.
  • the fourth condition is satisfied according to the invention either by the aid of neutrodyning, or by satisfying by way of choosing a special construction'for the twin-grid tube and the oscillator, and further by the addition of small capacitors, a condition that shall hereinafter be indicated.
  • Fig. 3 shows a method of coupling according to the invention which contrasted with the conventional arrangement shown in Fig. 1 increases selectivity, reduces the amplitude of the signal at the instant of frequency change, while insuring simple uni-control of the different capacities such as C2 and C3.
  • This end is attained'by coupling the filter L2 C2, L3 C3 with the control grid by the aid of a potentiometer R2 is the leak resistance of the grid, and the same is of an order of magnitude of 1 megohm.
  • RI should be chosen sufficiently high in order that the shunt constituted, for instance, by the capacity between the cathode and grid c' in series with C1L1 will not disturb the regulation of the circuit L3, C3.
  • RI on the other hand, should yet be made sufficiently small in order that an appreciable potential across the terminals of L3 should be transferred and fed to the control grid.
  • RI 40,000w is a size adapted to insure the desired results.
  • 1" represents a capacity serving to couple the two tuned circuits L2, C2 and L3, C3.
  • Z stands for the mean-frequency filter which is provided at the output end of the twin-grid tube.
  • Fig. 4 shows a modification wherein the two circuits (for instance) that constitute the filter are coupled by the mutual inductance M between the coils L2 L3 of the resonant input circuits, the upper end of coil L3 being connected to the signal control grid through a high resistance R1, as in Fig. 3. Since the lower end of L3 is grounded, R1 serves also as a grid leak and R2 is useless in this arrangement.
  • Fig. 5 shows a modification where one screen type tube L serves as an aperiodic coupling according to the invention, the resistance R1 consisting then of the very high internal resistance of this tube.
  • the plate of tube L is resistance coupled by the condenser r to the signal control grid of the oscillator-detcctor tube, the control grid of which is provided with the leakage resistor R2.
  • Fig. 6 shows another modification which will be self-understood and where the use of the resistance RI according to the invention makes it possible to practice uni-control of capacities C2, C3.
  • the invention further furnishes ways and means so as to insure simultaneously a more or less adequate fulfillment of the second and the third condition hereinbefore mentioned.
  • twin-grid tubes with accelerator grid (contra-distinct from screen grid twin-grid tubes) involving the properties of variable mu in reference to the control grid, such variable mu feature. being obtained by ways and means entirely similar to those nowadays known in regard to screen grid tubes. It further discloses the use of such twin-grid tubes comprising an accelerator grid and the variable mu feature for radio modulator twin-grid tubes for insuring frequency change.
  • an autodyne circuit scheme also according to the invention, it is possible to use for the autodyne tube a variable mu screen grid tube.
  • the tube is of variable mu according to the sense of this invention; but if gI is thecontrol grid,
  • the plate current 2 ⁇ ; expressed as a function of Vg will comprise terms of a high order with substantial coefficients for V l and far lower ones for V Z.
  • Fig. 713 there will be seen a twin-grid tube which involves the variable mu feature for both gl as well as 92.
  • C designates the cathode and P the plate.
  • Fig. 8 shows the characteristics of such a twingrid tube. There are shown by the solid lines the curves of the plate current and of the current of the first grid gl, for a certain potential applied to these two electrodes, as .a function of the potential of the control grid V 2. These characteristics present a very regular curvature, while the characteristics traced by broken lines of the ordinary twin-grid tube present rectilinear portions throughout a wide range of variation of V 2.
  • Equations (4) the functions of A, B, C, no longer contain terms of V of a high order and of substantial amplitude, and this always as a result of the variable mu property.
  • the stray whistling noises are thus greatly diminished for this two-fold reason, namely, that the construction intended to insure variable mu satisfies requirements and that in the following equation for V 5)
  • Vg ot sin wilH-p smmt
  • a sin wt has been greatly diminished, the variable mu twin-grid tube oscillating less strongly. It is true that this efiect manifests itself also in the form of a substantial reduction in sensitiveness; but it will be preferable to put up with this loss in order to insure a proper frequency-change process.
  • Fig. 9 illustrates in a suificiently evident way the means adapted to neutralize perfectly the capacities c c" by similar (or proportional) capacities according to whether the windings LI L2 are divided into equal (or proportional) parts.
  • the top of winding L1 is connected to the oscillator grid, the lower portion of this winding and condenser C providing a circuit to neutralize the capacity efiect between the two grids.
  • the plate output circuit is connected to a midpoint of the coil L2, whereby it is possible to neutralize the capacity between the plate and outer grid by connecting the lower end of L2 to this grid through the condenser C.
  • Fig. 10 shows a neutralizing arrangement that is far simpler, but efiicient only if the oscillator of the twin-grid tube is coupled very closely.
  • the reaction in the twin-grid tube due to c' and e" has the result of imparting to V 2 the following values, to wit:
  • Z (w) is the impedance encountered by the heterodyne wave w between the control grid and the filament return, expression (6) being valid only if the oscillator is coupled strongly.
  • the twin-grid tube for a given oscillator or of the oscillator for modulator twin-grid tube, but it is employed merely for producing the sum of voltages oz sin wit+x sin wt in Equation (5) which here assumes the shape of Equation (6) the said aggregate potential being applied to the grid of the detector tube of mean frequency E which preferably should be a variable mu tube resulting in extremely pure detection of median frequency.
  • the signal frequency is applied to the outer grid of tube B through the resistor RI, the
  • a vacuum tube having a cathode, a control grid, a second grid and a plate
  • a circuit tunable over a range of signal frequencies connected to the control grid and cathode said circuit comprising a plurality of similar tuned circuits and an aperiodic coupling between the last of said circuits and said control grid, a circuit tunable to: a desired oscillation frequency connected to the 1.
  • a plate circuit having a feedback connection to said last named circuit, the control grid being so constructed and arranged as to provide a variable mu characteristic to the current between the cathode and said second grid.
  • a vacuum tube detector having a cathode, a control grid, a second grid and a plate, a circuit tunable to a desired oscillation frequency connected between the second grid and cathode, a plate circuit having a feedback connection to said circuit, said second grid being so arranged with reference to said plate as to provide a variable mu plate current characteristic, means for neutralizing the capacity between the control grid and plate, a source of signal frequency energy and means connecting said source to the cathode and control grid, comprising two coupled circuits each having means for tuning it to the incoming signal frequency, and an aperiodic coupling between one of said coupled circuits and the control grid.
  • a source of high frequency energy a vacuum tube oscillator having a control grid, a second grid and a plate circuit, a feedback connection between the plate circuit and the second grid, a detector tube having a control grid, a screen grid and a plate circuit said control grid being constructed to provide a variable mu plate current characteristic, means connecting a positive source of potential to the screen grid, a circuit tuned to the intermediate frequency connected in said platecircuit, a connection conductive to direct current between the control grids of the tubes and an aperiodic coupling means connecting one of said control grids to the said source of energy.
  • a vacuum tube detector having a cathode. a control grid, a second grid and a plate, a circuit tunable to a desired oscillation frequency connected between the second grid and cathode, a plate circuit having a feedback connection to said circuit, a source of signal frequency energy, means for coupling said source to the cathode and control grid, said means comprising a plurality of similar resonant coupled circuits each tuned to the signal frequency and an aperiodic coupling means connecting the last of said circuits to said control grid, said control grid and said second grid being constructed and arranged to provide a variable mu plate current characteristic.
  • a vacuum tube detector having a cathode, a control grid, a second grid and a plate
  • a circuit tunable to a desired oscillation frequency connected between the second grid and cathode
  • a plate circuit having a feedback connection to said circuit
  • a source of signal frequency energy means coupling said source to the cathode and control grid
  • said second grid being constructed and arranged to provide a variable mu plate current characteristic whereby said tunable circuit is substantially free of harmonic frequencies of its oscillation frequency.
  • a vacuum tube having a cathode, a control grid, a second grid and a plate, an input circuit connected to said cathode and control grid, means for impressing radio frequency signal currents on said input circuit, a circuit tunable to a desired local oscillation frequency connected between the second grid and cathode, a plate circuit having a feedback connection to said tunable circuit, said control grid and said second grid being disposed in oppositely inclined planes with reference to said plate.
  • a radio receiver the combination of a vacuum tube detector having a cathode, a control grid, a second grid and a plate, a circuit tunable to a desired oscillation frequency connected between the second grid and cathode, a plate circuit having a feedback connection to said circuit, a source of signal frequency energy, coupling means arranged to connect said source to said control grid;'said second grid being inclined at an acute angle with reference to said plate so as to provide a variable mu plate current characteristic.
  • a superheterodyne receiver comprising the combination of a vacuum tube oscillator-detector having a cathode, a control grid and twoadditional cold electrodes, a circuit tuned to a desired oscillation frequency connected to one of said cold electrodes, a circuit connected to the other of said cold electrodes including a por-' tion having a feedback connection to said tuned circuit, a source of signal frequency energy and a circuit coupling said source to said control grid and including a portion resonant to the incoming signal frequency, said control grid being constructed of wire having a variable spacing between its adjacent portions whereby to provide a variable mu plate current characteristic.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Circuit Arrangement For Electric Light Sources In General (AREA)
  • Amplifiers (AREA)
US635370A 1932-01-30 1932-09-29 Radio receiver Expired - Lifetime US2064220A (en)

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FR2064220X 1932-01-30

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US2064220A true US2064220A (en) 1936-12-15

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US (1) US2064220A (enrdf_load_stackoverflow)
BE (1) BE392720A (enrdf_load_stackoverflow)
FR (1) FR745631A (enrdf_load_stackoverflow)

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FR745631A (enrdf_load_stackoverflow) 1933-05-13

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