US1941070A - Heterodyne wireless receiver - Google Patents

Description

Dec. 26, 1933. c. E. G BAILEY 1,941,070

HETERODYNE WIRELESS RECEIVER Filed Jan. 6, 1930 W W W VISA/ZZZ? 8% Ma/rrd 7 7 ORNEYS Patented Dec. 26, I

1mm STATES- PATEN FF-I E HETERODYNE WIRELESS RECEIVER 7 Christopher Edmund Gerva'se Bailey, London, England, as'sig'nor to Victdr'lalking Machine Company, a corporation of New Jersey appneeen January 1930,- Serial No. 418,931; a and in Great Britain January 9, 1929 'l'Claims. (crass-) The; present invention relates to .heterodyne'. put circuit of the first detector in order to shift wirelessreceivers and more particularly though the phase of one of these oscillations, br alter its notexclusively to receivers of the supersonic amplitude orboth to prevent annulment of the v heterodyne typ'e. ,i'requency f3.' The output from the nrst de- In raceivers of this type the received'high fretector 7 is then caused to, beat with the output m quency, oscillations at a frequency f1 are causcd from the radio frequency tuning device 1,, Zand tobeat with locally produced oscillations at a the resulting oscillations are fed to alsecond' frequency f2 and thereby to generate oscillations detector 9. r H q I atlabeat frequency is, which is known, as the The arrangement is such that local oscillations intermediate frequency and is equal to the sum are generated at frequenciesv f1 and is in con- '65 of or the difference between f1 and f2. ncction with devices, 4 and 5 respectively, de- According to the present invention locally genvice r being under control of the signal oserated oscillations in a heterodyne receiver are cillation frequency received in circuit l -2 3. produced. by beating together two oscillations, The combined frequencies f1 and bare passed one having a frequency equal to the intermethrough the first detector 7 and are applied to diate frequency. The other has preferably a the second detector 9 simultaneously with sigi'requency equal to that of the oscillations to be nals at the frequency 11 derived from the circuit received. .l- -2--3. The resulting interaction or beating One advantage of this arrangement is that of the signal frequency with the locally generated by making the local oscillator, which produces combined frequency'is such that the signal freoscillations at the frequency of the oscillations-to quency cancels out, leaving the intermediate frebe-received, in the form of a loosely coupled cirquency is to be transmitted through the amplifier cult itself loosely coupled to the aerial tuned including the tube or device 10, and to be applied circuit, the oscillations produced by this oscilto the third detector 11.

lator are pulled into step with the incoming It will thus be seen that the system above signals and beats are therefore produced at exdescribed includes means for deriving in the tube ac'tly the right frequency. 9, which is the second detector, the local hetero- One form of apparatus in accordance with the dyne or intermediate frequency from the depresent invention will be described, with refmodulation or detection or" two locally generated erence to the accompanying drawing, using the oscillation frequencies, one of which is the same references to denote-the various frequencies frequency to which the intermediateamplifier involved as were used earlier in the specification, is tuned andthe other of which is the signal A frame aerial 1 is adapted to be tuned by frequency. V I means of a variable condenser 2 to a frequency The oscillations from this detector 9 (at a fref1. This tuned circuit 1, 2 which may, if dequency is) are fed to: the intermediate frequency sired, also embody amplifying means, will be amplifier 10 and thence through a third de referred to as the radio frequency tuning device. s t 11 t an audio frequency amphfier Loosely coupled to the frame aerial 1 by mgansof One advantage of the arrangement according the coil 3 is an oscillator 4 which will be referred .7 to the present invention is that, Since the to as the radio f f Qscmator? adapted to cults l, 2 and 13, 14 have to be tuned to the same e e oscmamons a frequency, differences between the tuning inducoscillatoi 4 is tuned by means of the inductance tances may be allowed for b Sm tunm Con 13 and the variable condenser 14. Asecond oscildam l a y 1 g g lator 5, which will be referred to as the intere S g' g oafl.nmlc and the mediate frequency oscillator, adapted to generate g f u an without i fi l be m 6 local oscillations at a frequency is, is provided y tioupleq' I p finalpuumg mtg Sbfep 7 and the oscillations produced by beating the will be done by the carrier wave itself. The aerial oscillations from the intermediate frequency ostuner may thus be made more rselectlve than cillator 5 with the radio frequency oscillator are usual passed through the transformer 6 to a detector I the present example the Osclnator 4 15 5 device 7, known as the first detector AS the vided with a plate coil 15 inductively coupled to oscillations from this detector will be at freethe inductance 13 in the tuned circuit. quencies of both ,fi-i-jg and f1-f s e r a tiv The input circuit, comprising the aerial or color impedance device, such as a radio frequency lector 1, and input tuning condenser 2 are also 1 5' choke 8 of suitable value, is inserted in the outcoupled with the tuned circuit 13-44 by induc- 1'10 tive coupling between the coil 3 and the inductance 13.

The first detector 7 is coupled to the second detector 9 by a shunt feed circuit including the choke coil 8 from the plate end of which signal currents are taken through a coupling condenser 16 to the primary winding 1'7 of a coupling transformer 18, the secondary winding 19 of which is, in turn, coupled to the tube 9 through a grid condenser 20 and a grid leak 21.

I claim:

1. In a heterodyne Wireless receiver having a predetermined intermediate frequency, means for receiving modulated signal oscillations, means for generating and beating together two oscillations of different frequency, one of said oscillations having a frequency equal to: the intermediate frequency, and detector means for heterodyning said modulated signal oscillations with the resulting beat frequency to produce intermediate frequency signals.

2; A heterodyne wireless receiver according to claim 1 wherein the second of said oscillations has a frequency equal to the frequency to be received.

3. The method of radio signal reception, which comprises receiving modulated signal oscillations at a frequency fl, generating local oscillations at frequencies f1 and f3, causing said local oscillations to interact to produce oscillations at a frequency f2, causing said last named oscillations to beat with said signals to produce signal modulated oscillations at the frequency )3 and thereafter amplifying and detecting said last named oscillations.

4. The method as set forth in claim 3 further characterized in that the incoming signals are utilized to control the generation of the local oscillations at the signal-frequency f1.

5. In a signal receiving system, a receiving network, an oscillation generator, means for simultaneously tuning said network and generator to the same frequency, a second oscillation generator, means for deriving a beat frequency from the oscillations generated by said oscillators and means for impressing said beat frequency on said network.

6. The combination as set forth in claim 5 characterized in that the first mentioned oscillator is so coupled with the receiving network that 'an incoming signal is enabled to exert a measure of control over the frequency of the oscillations generated thereby.

7. A heterodyne wireless receiver comprising three oscillatory circuits, one of said circuits including an oscillation generator and being tunable to the intermediate frequency, the other two of said circuits including means whereby said circuits may be tuned to the same signal frequency, one of the two last named circuits being coupled with an oscillation'generator, means for deriving a beat frequency from said oscillation generator circuits, means for combining said beat frequency with the signal frequency to provide oscillations at said intermediate frequency, and means for detecting signals at said intermediate frequency.

CHRISTOPHER EDMUND GERVASE BAILEY.

Images