US2116501A - Radio receiving system - Google Patents

Radio receiving system Download PDF

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Publication number
US2116501A
US2116501A US40544A US4054435A US2116501A US 2116501 A US2116501 A US 2116501A US 40544 A US40544 A US 40544A US 4054435 A US4054435 A US 4054435A US 2116501 A US2116501 A US 2116501A
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US
United States
Prior art keywords
frequency
amplitude
signal
oscillator
current
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
US40544A
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English (en)
Inventor
Edwin H Armstrong
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Individual
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Individual
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Filing date
Publication date
Priority to NL46606D priority Critical patent/NL46606C/xx
Application filed by Individual filed Critical Individual
Priority to US40544A priority patent/US2116501A/en
Priority to GB24940/36A priority patent/GB481526A/en
Priority to FR810606D priority patent/FR810606A/fr
Application granted granted Critical
Publication of US2116501A publication Critical patent/US2116501A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • H04B1/30—Circuits for homodyne or synchrodyne receivers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D3/00—Demodulation of angle-, frequency- or phase- modulated oscillations
    • H03D3/02—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal
    • H03D3/24—Modifications of demodulators to reject or remove amplitude variations by means of locked-in oscillator circuits
    • 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
    • H04B1/10—Means associated with receiver for limiting or suppressing noise or interference

Definitions

  • This invention relates to a method of improving the operation of the receiving apparatus described in my U. S. Patent No. 1,941,069.
  • the object of the invention is to' improve the signal to noise ratio so that communication may be effected over greater distances or with a minimum of power over a given. distance.
  • the frequency deviations which can be set up in the receiver by natural disturbances are relatively small at the modulation frequencies when compared to those produced by the transmitter; the response to natural disturbances is much reduced and the ratio of the amount of noise with respect to the signal is much improved.
  • the operation of the system is strictly quantitative as long as the signal carrier is greater in amplitude than the amplitude of the disturbances and the signal to noise ratio can be reduced to practically any desired ratio by increasing the deviation of the transmitted wave with respect to the frequency of modulation and proportioning the receiver to it. Under these conditions where the signalcarrier is greater in amplitude than the amplitude of the disturbing currents they usually manifest themselves in the speaker as av hiss of uniform amplitude.
  • This method 5 consists in providing at the receiving station a local oscillation which is greater in amplitude than that of the received signal and which has the characteristic of synchronizing readily and remaining in synchronism with the incoming -signal as it varies in frequency in accordance with the modulations impressed upon it.m
  • the combined currents of the local oscillation and the incoming signal become then in effect a new signal having an amplitude greater than the disturbing currents so that it is no longer possible for these currents to cancel out the signal.
  • This method is also effective when the amplitude of the disturbing current is small compared to the amplitude of the signaling current as it is the relative amplitudes of the two which determine the signal-noise ratio in the speaker. .As av consequence of this the hiss type of disturbance can also be greatly reduced.
  • FIG. 1 illustrates an arrangement for carrying out the method of the invention.
  • Fig. 2 illustrates an alternative way of producing the same result.
  • i-2 represents the antennasystem
  • 3 an amplifier for the received currents
  • I a rectifier and 5 an oscillator for converting the incoming frequency to an intermediate value
  • 6 an amplier for the interme- 35 diate frequency and l a rectifier for this frequency
  • 8 is an oscillator for converting the first intermediate frequency to a lower intermediate frequency.
  • S-il represents a three stage amplifier for this second intermediate frequency 40 and i8 current limiter therefor.
  • i9 is a filtering system for removing harmonics created by the current limiter.
  • is a rectiier oscillator combination for changing the second interme-1 diate frequency to a third intermediate frequency.
  • 22 is an amplifying system for the third intermediate frequency and 23, 24 a system for translating the variations in frequency in the third intermediate frequency into amplitude variations and detecting them in the manner described in the patent to which reference has already been made.
  • the manner of operation of the system is as follows:
  • the currents set up in the antenna are duly amplified and converted by the system 3-8 65 into currents of the second intermediate frequency and supplied to the input of the ampli-A bomb 9I1.
  • This amplifier is so, designed that it will oscillate over a. wide range of frequency and can be'readily synchronized with a current applied toits input. This is accomplished by winding the coils I0, I3 and I8 with resistance wire and shunting them by resistances Il, i4 and I1.
  • By adjusting the amount of amplification it is possible to setup an oscillation of the proper strength in the system so that it will readily synchronize with the signaling current. If the adjustments have been properly made and if the incoming signal is not too weak relatively to the strength of the local oscillation then the local oscillation will follow the deviations of the incoming signal thruout its course.
  • the amplifiers 3 and 6 are used ahead'of the oscillating system '9-I1.
  • the amplifying system 9-I'I is given a frequency of its own.
  • the output of the current limiter I8 is hardly suilicient to operate the translating and detecting system well without further amplification, the necessary amplitude is obtained by converting to a third intermediate frequency, amplifying that frequency and then performing the operations of translation and detection.
  • Fig; 2 illustrates an arrangement which employs a single oscillator as the source of the local oscillation instead of the multi-stage oscillator of the system of Fig. 1. While the fundamental principle of synchronizing a local oscillator with an incoming signal is the same as in Fig. 1 the method of carrying it out is different.
  • a single tube oscillator is desirable because it is more readily controllable in its adjustment. Because of this greater controllability it is less amenable to synchronization than a multi-stage oscillator and will follow the incoming frequency thru a range which is a lower percentage of its mean frequency than will the multi-stage oscillator.
  • the frequency of oscillation of the local source is suiiiciently high the percentage of this frequency' thru which the local source will keep in step with the signal will be equal numerically to thenumber of cycles actual deviation of the incoming signal. Therefore the expedient is adopted of selecting son'ie high frequency of oscillation, amplifying the incoming signal by ordinary superheterodyne methods and then heterodyning the output of the last intermediate frequency current up in frequency to a sufficiently high value to match the frequency of the oscillator. After synchronizing the local oscillation the combinedn currents are heterodyneddown in frequency to some suitable value, amplified, limited, translated into amplitude variations and detected.
  • 21-33 represents a two intermediate frequency superheterodyne amplifier.
  • the two intermediate amplifiers 30 and 33 are each successively lower in frequency than the radio frequency amplifier 21. and 35 an oscillator for heterodyning up the frequency of the output of 33 toa value which coinsides with that of the oscillating system iii-40. ⁇
  • the oscillator is isolated from reactions 'which may be produced by the rest of the circuits by the input and output blocking tubes 36 and 4
  • the synchronized signaling andl local currents are 34 is a rectifier heterodyned down in frequency again by the rectifier 42 and oscillator 43, amplifiedby 44, limited by 45,. the harmonics removed by thel filter 46, and the resulting current amplified translated and detected by 41, 43, 49 in the manner described in my patents previously referred to.
  • the method of reducing interference in radio reception of frequency modulated waves Iwhich consists in generating at the receiving station a local oscillation greater in'amplitude than that of the received signal, synchronizing the local oscillation with the received oscillations, removing amplitude changes from the synchronized oscillations, and detecting the changes in frequency.
  • a system for reducing interference in radio reception of frequency modulated waves comprising means at the receiver for providing local oscillations greater in amplitude than that of the received signal, means for synchronizing said local oscillations with the received oscillations and combining the same, means responding to said combined oscillations to produce oscillations varying in frequency but not in amplitude,

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Noise Elimination (AREA)
  • Circuits Of Receivers In General (AREA)
US40544A 1935-09-14 1935-09-14 Radio receiving system Expired - Lifetime US2116501A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
NL46606D NL46606C (fr) 1935-09-14
US40544A US2116501A (en) 1935-09-14 1935-09-14 Radio receiving system
GB24940/36A GB481526A (en) 1935-09-14 1936-09-12 Improvements in or relating to radio receiving systems
FR810606D FR810606A (fr) 1935-09-14 1936-09-14 Perfectionnements aux systèmes radio-récepteurs

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US40544A US2116501A (en) 1935-09-14 1935-09-14 Radio receiving system

Publications (1)

Publication Number Publication Date
US2116501A true US2116501A (en) 1938-05-10

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ID=21911560

Family Applications (1)

Application Number Title Priority Date Filing Date
US40544A Expired - Lifetime US2116501A (en) 1935-09-14 1935-09-14 Radio receiving system

Country Status (4)

Country Link
US (1) US2116501A (fr)
FR (1) FR810606A (fr)
GB (1) GB481526A (fr)
NL (1) NL46606C (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2454814A (en) * 1941-08-30 1948-11-30 Int Standard Electric Corp Interference reducing radio receiver
US2462224A (en) * 1944-09-02 1949-02-22 Philco Corp Noise reducing radio receiver
US2525634A (en) * 1945-12-07 1950-10-10 Rca Corp Pulse communication system
US2607888A (en) * 1944-07-24 1952-08-19 Cossor Ltd A C Radio signal discriminating apparatus
US3010094A (en) * 1957-09-30 1961-11-21 Honeywell Regulator Co Electrical data handling apparatus

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116584714B (zh) * 2023-07-18 2023-10-20 杭州拓尔微电子有限公司 启动控制装置、电子雾化器及其模组

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2454814A (en) * 1941-08-30 1948-11-30 Int Standard Electric Corp Interference reducing radio receiver
US2607888A (en) * 1944-07-24 1952-08-19 Cossor Ltd A C Radio signal discriminating apparatus
US2462224A (en) * 1944-09-02 1949-02-22 Philco Corp Noise reducing radio receiver
US2525634A (en) * 1945-12-07 1950-10-10 Rca Corp Pulse communication system
US3010094A (en) * 1957-09-30 1961-11-21 Honeywell Regulator Co Electrical data handling apparatus

Also Published As

Publication number Publication date
GB481526A (en) 1938-03-14
FR810606A (fr) 1937-03-24
NL46606C (fr)

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