GB654523A - Image rejection circuits for superheterodyne receivers - Google Patents

Image rejection circuits for superheterodyne receivers

Info

Publication number
GB654523A
GB654523A GB17108/48A GB1710848A GB654523A GB 654523 A GB654523 A GB 654523A GB 17108/48 A GB17108/48 A GB 17108/48A GB 1710848 A GB1710848 A GB 1710848A GB 654523 A GB654523 A GB 654523A
Authority
GB
United Kingdom
Prior art keywords
oscillator
mixer
fed
image
output
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
Application number
GB17108/48A
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.)
STC PLC
Original Assignee
Standard Telephone and Cables PLC
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 Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Publication of GB654523A publication Critical patent/GB654523A/en
Expired legal-status Critical Current

Links

Classifications

    • 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
    • H03D7/18—Modifications of frequency-changers for eliminating image frequencies

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Developing Agents For Electrophotography (AREA)
  • Oscillators With Electromechanical Resonators (AREA)
  • Superheterodyne Receivers (AREA)

Abstract

654,523. Superheterodyne receivers. STANDARD TELEPHONES & CABLES; Ltd. June 25, 1948, No. 17108. Convention date, Sept. 17, 1947. [Class 40 (v)] A frequency conversion arrangement designed for image frequency rejection comprises a first mixer 11 fed with a signal Fs and with the output Fo from an oscillator 12 to produce a first I.F. which, after filtering at 13, is fed to a second mixer 14 together with the oscillations from oscillator 12 and oscillations Fc from a crystal-controlled oscillator 15. This eliminates the local oscillation Fo, and the second I.F.= Fc - Fs is selected by a filter 17 and fed to the subsequent stages. Oscillator 12 is modulated at a low rate over a band E, but this deviation is, for the desired signal Fs, eliminated at the second mixer 14. For the image signal however, the error is doubled, so that the image I.F. is greatly attenuated by band-pass filter 17. In a modification, the output from the crystal oscillator is mixed with that of the oscillator 12 in a third mixer, a selected output being then fed to mixer 14.
GB17108/48A 1947-09-17 1948-06-25 Image rejection circuits for superheterodyne receivers Expired GB654523A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US654523XA 1947-09-17 1947-09-17

Publications (1)

Publication Number Publication Date
GB654523A true GB654523A (en) 1951-06-20

Family

ID=22062801

Family Applications (1)

Application Number Title Priority Date Filing Date
GB17108/48A Expired GB654523A (en) 1947-09-17 1948-06-25 Image rejection circuits for superheterodyne receivers

Country Status (1)

Country Link
GB (1) GB654523A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2705304A (en) * 1954-04-19 1955-03-29 Rca Corp Bridge demodulator circuit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2705304A (en) * 1954-04-19 1955-03-29 Rca Corp Bridge demodulator circuit

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