GB678533A - Arrangements for measuring non-linear distortion in frequency modulation communicating systems - Google Patents

Arrangements for measuring non-linear distortion in frequency modulation communicating systems

Info

Publication number
GB678533A
GB678533A GB1365950A GB1365950A GB678533A GB 678533 A GB678533 A GB 678533A GB 1365950 A GB1365950 A GB 1365950A GB 1365950 A GB1365950 A GB 1365950A GB 678533 A GB678533 A GB 678533A
Authority
GB
United Kingdom
Prior art keywords
frequency
oscillator
wave
modulation
amplitude
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
GB1365950A
Inventor
Bert Bulow Jacobsen
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
Priority to GB1365950A priority Critical patent/GB678533A/en
Publication of GB678533A publication Critical patent/GB678533A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
    • G01R29/06—Measuring depth of modulation

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Monitoring And Testing Of Transmission In General (AREA)

Abstract

678,533. Frequency modulation distortion measurements. STANDARD TELEPHONES & CABLES, Ltd. May 31, 1950, No. 13659/50. Class 37. [Also in Group XL (c)] Non-linear distortion in frequency and phase modulation systems of communication is measured in such a way that the various sources of the distortion can be separated and that non- linearity of the measuring means does not introduce error. An arrangement is shown for measuring non-linear distortion produced in the generation of frequency-modulated waves. The oscillator 1 to be tested generates a carrier wave of frequency f<SP>1</SP>. A similar oscillator 2 is set to generate a carrier wave of frequency f<SP>2</SP>. A signal wave of frequency p is applied directly to frequency modulate the oscillator 1 and is also applied to frequency modulate the oscillator 2 through an amplitude and phase adjuster 3. A second signal wave of frequency q different from p is also applied to frequencymodulate the oscillator 1 simultaneously with the p wave. The frequency-modulated waves f<SP>1</SP>, f<SP>2</SP> are applied to an amplitude modulator or frequency changer 4, the difference frequency #<SP>1</SP>-#<SP>2</SP> being selected by a filter 5 and passed through an amplifier 6 to a frequency discriminator and amplitude limiter 7. The adjuster 3 is set so that the amplitude and phase. of the p wave which modulates the oscillator 2 is such that the modulation component at the frequency p derived from the oscillator 2 cancels out the same component derived from the oscillator 1 and the side-band #<SP>1</SP> - #<SP>2</SP> does not bear any modulation component of frequency p. One of the components q+p is selected by a narrow band-pass filter 8 from the output of the discriminator 7 and its level with respect to the level of the wave q is measured by an instrument 9, thereby determining the degree of non-linearity of the frequency modulation characteristic of the oscillator 1 without the introduction of appreciable errors due to non-linearity of the discriminator characteristic.
GB1365950A 1950-05-31 1950-05-31 Arrangements for measuring non-linear distortion in frequency modulation communicating systems Expired GB678533A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1365950A GB678533A (en) 1950-05-31 1950-05-31 Arrangements for measuring non-linear distortion in frequency modulation communicating systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1365950A GB678533A (en) 1950-05-31 1950-05-31 Arrangements for measuring non-linear distortion in frequency modulation communicating systems

Publications (1)

Publication Number Publication Date
GB678533A true GB678533A (en) 1952-09-03

Family

ID=10027061

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1365950A Expired GB678533A (en) 1950-05-31 1950-05-31 Arrangements for measuring non-linear distortion in frequency modulation communicating systems

Country Status (1)

Country Link
GB (1) GB678533A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3227949A (en) * 1959-01-15 1966-01-04 Telefunken Gmbh Method and apparatus to measure the transmission characteristics of four terminal networks
DE1766716B1 (en) * 1967-07-10 1971-06-24 Marccni Instr Ltd SIGNAL GENERATOR FOR GENERATING FREQUENCY MODULATED WAVES

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3227949A (en) * 1959-01-15 1966-01-04 Telefunken Gmbh Method and apparatus to measure the transmission characteristics of four terminal networks
DE1766716B1 (en) * 1967-07-10 1971-06-24 Marccni Instr Ltd SIGNAL GENERATOR FOR GENERATING FREQUENCY MODULATED WAVES

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