US2314785A - Radio receiver - Google Patents

Radio receiver Download PDF

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Publication number
US2314785A
US2314785A US432589A US43258942A US2314785A US 2314785 A US2314785 A US 2314785A US 432589 A US432589 A US 432589A US 43258942 A US43258942 A US 43258942A US 2314785 A US2314785 A US 2314785A
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United States
Prior art keywords
oscillator
intermediate frequency
local
reception
valve
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
Application number
US432589A
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English (en)
Inventor
Holland John Douglas
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
International Standard Electric Corp
Original Assignee
International Standard Electric Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by International Standard Electric Corp filed Critical International Standard Electric Corp
Application granted granted Critical
Publication of US2314785A publication Critical patent/US2314785A/en
Anticipated expiration legal-status Critical
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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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/02—Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation
    • H04L27/06—Demodulator circuits; Receiver circuits
    • H04L27/063—Superheterodyne receivers

Definitions

  • This desensitising of the receiver or amplifier can be partially avoided by the well known expedient of supplying a delay voltage so that the controlled valves are not affected by injection voltage due to the local C. W. oscillator. It will then be found, however, that the delay voltage will not be of the correct value for the reception of modulated signals with the local C. W. oscillator switched off. Alternatively, as acompromise, the strength of the local C. W. oscillator may be reduced, but it will then be found that it may be easily pulled into step or zero beat by a strong signal. Furthermore, the theoretically desirable condition that the local C. W. oscillator should be stronger than the signal will not always be met. Moreover, the strength of the local oscillator will also determine the strength of the harmonics it produces. These harmonics may occur at a frequency where signal frequency reception is desired.
  • the continuous oscillations for beating with the intermediate frequency are combined with the in ⁇ termediate frequency in a stage separate from the intermediate frequency amplifier having automatic gain control and having a minimum of coupling with the said intermediate frequency 'Y amplifying stage having the automatic gain con-'fl trol.
  • the triocle portion is completed by an anode AI,k
  • sistancel Rl and capacity C4 are provided in Well known manner.
  • the intermediate frequency continuous wave signals are applied between the terminal A and earth.
  • the lead from terminal A to earth includes an inductance LI which is coupled to another inductance L2 connected between grid g3 which functions as a control grid, and the cathode K via resistance RI.
  • L2 is a low impedance coupling coil, and LI may be part of a tuned circuit at intermediate frequency.
  • the anode A2 receives its high tension voltage Via terminal H.T. ⁇ via antiresonant circuit L3, Cl tuned to the difference frequency obtained between the intermediate frequency signal and the local beat oscillator, and the grids g2, g4 receive a positive voltage from H.T.- ⁇ via resistance R4.
  • the anode AI of the local heterod'yne oscillator receives its high tension voltage also from II.T.+ Via an adjustable tap on the inductance L4.
  • This lead includes a switch S2 so that when reception of modulated signals is desired, the local oscillator can be put out of action.
  • the output from the valve VI is applied via a switch Si and resistance-capacity coupling C5, R2 to a low frequency amplifier V2 shown as a triode thermionic valve,
  • the invention will be better understood-from the grid g of V2 being connected to an adjustable tap on R2 which thus acts as a volume control.
  • the switch SI is a change-over switch, one terminal C of which is connected to the output circuit of valvev VI as already stated and the other terminal D is connected at B to the output from the rectifier stage (not shown) of a receiver for speech reception.
  • a pair of headphones H or other signal indicating device is connected in the output circuit of the low frequency ampliiier V2.
  • the oscillator is tuned to a frequency which differs from v the intermediate frequency received by some 1000 cycles.
  • the switch Si is closed on terminal C as shown and switch S2 is closed the oscillations from the grid g3 and the oscillations produced by the local oscillator (Al, g1, K) will amplifier system and the local C. W. oscillator is negligible as only a small portion of the total intermediate frequency voltage is applied between g3 and ground, and the circuits of the C. W. oscillator comprising L4C3 and the triode portion of VI outside the valve are separated from the circuits of the hexode portion outside the valve.
  • the local heterodyne oscillator can be set for optimum conversion gain in the valve VI without affecting the delay voltage that is associated with the rectification diodes (not shown) that are part of the intermediate frequency amplifier and pulling into step of the local oscillator by an incoming signal is remote due to the screening within the valve and also by using electronic coupling between the C. W. oscillator and the circuit of the signal at intermediate frequency.
  • CI and L3 By critical dimensioning of CI and L3 a good note lter effect can be obtained, the damping of the lter being small due to the input impedance, namely, that of the hexode portion of VI, and the output impedance C5, R2 being of high value. If a note filtering effect is not required, CI, L3 may be replaced by a resistance of suitable value.
  • Another advantage of the circuit arrangement described is that by providing a two channel path, namely, one for continuous wave signals and one for speech signals, the circuit design for both is simplified.
  • a superheterodyne receiver of the type having an intermediate frequency wave circuit including an intermediate frequency amplifier adapted for the reception of continuous or speech modulated waves having automatic volume control means connected therewith, and a local oscillator for supplying a continuous wave to beat with the amplied continuous wave from said intermediate frequency amplifier, the combina-tion including electronic means for producing a beat wave in response to waves from said intermediate frequency amplier and said oscillator, said oscillator being velectronically coupled with said beat producing means.
  • said beat producing means and said oscillator each include cathode, anode, and grid electrodes, said grid and anode of said beat producing means being separate from said oscillator grid ⁇ and anode, said oscillator cathode and grid being common to said beat producing means.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Superheterodyne Receivers (AREA)
US432589A 1941-02-07 1942-02-27 Radio receiver Expired - Lifetime US2314785A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1633/41A GB547737A (en) 1941-02-07 1941-02-07 Improvements in or relating to radio receivers

Publications (1)

Publication Number Publication Date
US2314785A true US2314785A (en) 1943-03-23

Family

ID=9725316

Family Applications (1)

Application Number Title Priority Date Filing Date
US432589A Expired - Lifetime US2314785A (en) 1941-02-07 1942-02-27 Radio receiver

Country Status (3)

Country Link
US (1) US2314785A (fr)
FR (1) FR931748A (fr)
GB (1) GB547737A (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2577489A (en) * 1944-11-03 1951-12-04 Hartford Nat Bank & Trust Co Mixing circuit employing compensation for electron stream induction effect
US2593349A (en) * 1947-11-01 1952-04-15 Rca Corp Beat frequency oscillator for receivers
US2726327A (en) * 1953-01-27 1955-12-06 Raytheon Mfg Co Mixer circuits
US3018372A (en) * 1958-02-17 1962-01-23 Sarkes Tarzian High frequency tuner

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2577489A (en) * 1944-11-03 1951-12-04 Hartford Nat Bank & Trust Co Mixing circuit employing compensation for electron stream induction effect
US2593349A (en) * 1947-11-01 1952-04-15 Rca Corp Beat frequency oscillator for receivers
US2726327A (en) * 1953-01-27 1955-12-06 Raytheon Mfg Co Mixer circuits
US3018372A (en) * 1958-02-17 1962-01-23 Sarkes Tarzian High frequency tuner

Also Published As

Publication number Publication date
GB547737A (en) 1942-09-09
FR931748A (fr) 1948-03-02

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