GB998437A - Improvements in and relating to attenuating circuit arrangements - Google Patents

Improvements in and relating to attenuating circuit arrangements

Info

Publication number
GB998437A
GB998437A GB218164A GB218164A GB998437A GB 998437 A GB998437 A GB 998437A GB 218164 A GB218164 A GB 218164A GB 218164 A GB218164 A GB 218164A GB 998437 A GB998437 A GB 998437A
Authority
GB
United Kingdom
Prior art keywords
amplifier
circuit
bridge circuit
voltage
control voltage
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
GB218164A
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.)
PHILLIPS ELECTRIC AND ASSOCIAT
Original Assignee
PHILLIPS ELECTRIC AND ASSOCIAT
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 PHILLIPS ELECTRIC AND ASSOCIAT filed Critical PHILLIPS ELECTRIC AND ASSOCIAT
Publication of GB998437A publication Critical patent/GB998437A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G1/00—Details of arrangements for controlling amplification
    • H03G1/0005—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal
    • H03G1/0035—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal using continuously variable impedance elements
    • H03G1/0052—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal using continuously variable impedance elements using diodes
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/3005—Automatic control in amplifiers having semiconductor devices in amplifiers suitable for low-frequencies, e.g. audio amplifiers
    • H03G3/301—Automatic control in amplifiers having semiconductor devices in amplifiers suitable for low-frequencies, e.g. audio amplifiers the gain being continuously variable
    • H03G3/3015—Automatic control in amplifiers having semiconductor devices in amplifiers suitable for low-frequencies, e.g. audio amplifiers the gain being continuously variable using diodes or transistors
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/32—Automatic control in amplifiers having semiconductor devices the control being dependent upon ambient noise level or sound level
    • 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

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Control Of Amplification And Gain Control (AREA)
  • Amplifiers (AREA)

Abstract

998,437. Automatic volume control circuits. PHILIPS ELECTRICAL INDUSTRIES Ltd. Jan. 17, 1964, No. 2181/64. Heading H4R. In an automatic volume control circuit an alternating control voltage is rectified and controls the attenuation of a bridge circuit of voltage dependent impedances in the input circuit of an amplifier, the output of the amplifier being positively fed back to a balance point associated with the bridge circuit. Fig. 1 shows the preferred form of the invention in which signals applied to terminals 2 pass via a variable attenuating bridge circuit 3 to the input of an amplifier 1. The attenuation of the bridge circuit 3 is controlled in accordance with the level of an alternating control voltage from a source 5, which may be a microphone responsive to the ambient noise level in order that the level from the amplifier 1 may increase as the ambient noise level increases and vice versa. The alternating control voltage from source 5 is amplified in amplifier 4 and transistors 6 and 7 then rectified by diodes 8 and 9 and the resulting D.C. potential is applied to control the impedance of the rectifier bridge 3. In order that the bridge circuit 3 is virtually floating with respect to earth positive feed-back is applied from the output to a tapping on resistor 14, a point balanced with respect to the D.C. control voltage. The feed-back results in a signal appearing on points 29 and 30 virtually equivalent to the input voltage on terminals 2 and thus minimizes the effect of non-linearity of circuit 3 on the signal fed to amplifier 1. Diodes 24 and 25 are provided in the control signal path to give an amplitude characteristic which compensates for the non-linear characteristic of the rectifier bridge 3.
GB218164A 1963-01-22 1964-01-17 Improvements in and relating to attenuating circuit arrangements Expired GB998437A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL288054 1963-01-22

Publications (1)

Publication Number Publication Date
GB998437A true GB998437A (en) 1965-07-14

Family

ID=19754369

Family Applications (1)

Application Number Title Priority Date Filing Date
GB218164A Expired GB998437A (en) 1963-01-22 1964-01-17 Improvements in and relating to attenuating circuit arrangements

Country Status (5)

Country Link
AT (1) AT239859B (en)
DE (1) DE1188665B (en)
DK (1) DK109570C (en)
GB (1) GB998437A (en)
SE (1) SE307976B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2289583A (en) * 1994-05-04 1995-11-22 Gilden Research Ltd Controlling audio level in dependence on ambient noise

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3649760A (en) * 1969-07-22 1972-03-14 Roger C Glidden Bandpass amplifier circuit
DE3114770C2 (en) * 1981-04-11 1984-02-02 ANT Nachrichtentechnik GmbH, 7150 Backnang Circuit arrangement for peak value rectification

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2289583A (en) * 1994-05-04 1995-11-22 Gilden Research Ltd Controlling audio level in dependence on ambient noise
GB2289583B (en) * 1994-05-04 1999-06-23 Gilden Research Ltd Adaptive audio system

Also Published As

Publication number Publication date
DE1188665B (en) 1965-03-11
AT239859B (en) 1965-04-26
SE307976B (en) 1969-01-27
DK109570C (en) 1968-05-13

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