GB875063A - Improvements in or relating to signal expanders - Google Patents

Improvements in or relating to signal expanders

Info

Publication number
GB875063A
GB875063A GB3151956A GB3151956A GB875063A GB 875063 A GB875063 A GB 875063A GB 3151956 A GB3151956 A GB 3151956A GB 3151956 A GB3151956 A GB 3151956A GB 875063 A GB875063 A GB 875063A
Authority
GB
United Kingdom
Prior art keywords
control current
circuit
junction
signal
expansion
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
GB3151956A
Inventor
John Roy Jarvis
Douglas Thomson
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.)
Post Office
Original Assignee
Post Office
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 Post Office filed Critical Post Office
Priority to GB3151956A priority Critical patent/GB875063A/en
Publication of GB875063A publication Critical patent/GB875063A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G7/00—Volume compression or expansion in amplifiers
    • H03G7/06—Volume compression or expansion in amplifiers having semiconductor devices

Landscapes

  • Tone Control, Compression And Expansion, Limiting Amplitude (AREA)

Abstract

875,063. Volume expansion. POSTMASTER GENERAL. Oct. 23, 1957 [Oct. 16, 1956], No. 31519/56. Class 40 (4). [Also in Group XL (c)] A volume expansion circuit comprises a junction-type rectifier, which derives from the input signal a control current which is applied to the emitter-base circuit of a junction transistor amplifier in the signal transmission circuit. As shown the signal received over terminals 1, 2 is amplified by the junction transistor TX4 whose output is rectified by junction transistor TX 5 to provide a control current I c . The input impedance presented to the transistor TX5 is arranged to be high so that the control current I c is strictly proportional to the input signal. The control current is applied to the emitterbase circuit of the junction transistors TX6, TX7 operating in push-pull in the signal transmission path. Since the emitter-base A.C. resistance is inversely proportional to the control current, then with the input impedance R 3 of this circuit made small, the gain of the circuit is directly proportional to the control current. As a result an expansion law of 2: 1 (measurements in decibels) is obtained. The arrangement permits of considerable variations in the characteristics of the transistors without affecting the expansion law. The Provisional Specification states that the expander may be put into the negative feedback loop of a highgain amplifier in order to produce a compressor.
GB3151956A 1956-10-16 1956-10-16 Improvements in or relating to signal expanders Expired GB875063A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB3151956A GB875063A (en) 1956-10-16 1956-10-16 Improvements in or relating to signal expanders

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3151956A GB875063A (en) 1956-10-16 1956-10-16 Improvements in or relating to signal expanders

Publications (1)

Publication Number Publication Date
GB875063A true GB875063A (en) 1961-08-16

Family

ID=10324300

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3151956A Expired GB875063A (en) 1956-10-16 1956-10-16 Improvements in or relating to signal expanders

Country Status (1)

Country Link
GB (1) GB875063A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1267262B (en) * 1965-03-10 1968-05-02 Standard Elektrik Lorenz Ag Method and circuit arrangement for temperature compensation of an amplitude expander
US3538351A (en) * 1965-03-10 1970-11-03 Int Standard Electric Corp Circuit arrangement for an amplitude expandor in the electric telecommunication engineering
EP0002972A1 (en) * 1977-12-16 1979-07-11 Thomson-Csf Amplifier device with self adaptive dynamic range and receiver using such a device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1267262B (en) * 1965-03-10 1968-05-02 Standard Elektrik Lorenz Ag Method and circuit arrangement for temperature compensation of an amplitude expander
US3538351A (en) * 1965-03-10 1970-11-03 Int Standard Electric Corp Circuit arrangement for an amplitude expandor in the electric telecommunication engineering
EP0002972A1 (en) * 1977-12-16 1979-07-11 Thomson-Csf Amplifier device with self adaptive dynamic range and receiver using such a device

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