GB1342383A - Signal compression and expansion systems - Google Patents

Signal compression and expansion systems

Info

Publication number
GB1342383A
GB1342383A GB2105071A GB2105071A GB1342383A GB 1342383 A GB1342383 A GB 1342383A GB 2105071 A GB2105071 A GB 2105071A GB 2105071 A GB2105071 A GB 2105071A GB 1342383 A GB1342383 A GB 1342383A
Authority
GB
United Kingdom
Prior art keywords
signal
amplifier
counter
line
gain
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
GB2105071A
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.)
BAE Systems Electronics Ltd
Original Assignee
Marconi Co Ltd
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 Marconi Co Ltd filed Critical Marconi Co Ltd
Publication of GB1342383A publication Critical patent/GB1342383A/en
Expired legal-status Critical Current

Links

Classifications

    • 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
    • H04B1/62—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 for providing a predistortion of the signal in the transmitter and corresponding correction in the receiver, e.g. for improving the signal/noise ratio
    • H04B1/64—Volume compression or expansion arrangements
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G7/00—Volume compression or expansion in amplifiers
    • H03G7/002—Volume compression or expansion in amplifiers in untuned or low-frequency amplifiers, e.g. audio amplifiers
    • H03G7/005—Volume compression or expansion in amplifiers in untuned or low-frequency amplifiers, e.g. audio amplifiers using discontinuously variable devices, e.g. switch-operated

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Multimedia (AREA)
  • Compression, Expansion, Code Conversion, And Decoders (AREA)
  • Reduction Or Emphasis Of Bandwidth Of Signals (AREA)
  • Tone Control, Compression And Expansion, Limiting Amplitude (AREA)

Abstract

1342383 Automatic gain control MARCONI CO Ltd 19 April 1971 [3 Aug 1970] 21050/71 Heading H4R In an analog signal transmission system employing compression and expansion, the compression device comprises a substantially linear transfer device the gain of which is varied in step-wise fashion by a bidirectional counter controlled by a comparator arranged to compare the envelope of the amplifier output with a reference and the expansion device includes a second substantially linear transfer device driven by a second bidirectional counter driven in complementary fashion. As shown an input signal Vi is amplified by a linear amplifier 10 and applied to an envelope detector 18 of diode type. The resulting envelope signal on a line 20 is applied to a comparator 22 which produces a positive, zero or negative potential on a line 26 depending on whether the signal on line 20 is more than a fixed amount below a reference potential Vr, differs from the reference by less than the fixed amount or is more than the fixed amount above the reference potential respectively. A positive signal on line 26 causes a counter 16 to step upwardly for each pulse from a clock 28 while a negative signal causes it to step down. Stepping of the counter in one direction or the other causes a change in the code markings on the counter outputs C1, C2, &c., the markings operating switches which connect appropriate resistors in the amplifier feed-back path and/or in series with the amplifier causing a gain change which tends to restore the original output level. The switches may be M.O.S. transistors which may form part of an integrated circuit. The output Vn and information relating to changes in gain may be transmitted to a receiving station using P.C.M., as Delta modulation or amplitude or frequency modulation of a carrier. At the receiving station the original signal is reconstituted in similar fashion, the stepping in the receiver being in accordance with the received information. In a modification the reference input Vr is derived from Vi by means of a non-linear amplifier.
GB2105071A 1970-08-03 1971-04-19 Signal compression and expansion systems Expired GB1342383A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT6966770 1970-08-03

Publications (1)

Publication Number Publication Date
GB1342383A true GB1342383A (en) 1974-01-03

Family

ID=11312589

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2105071A Expired GB1342383A (en) 1970-08-03 1971-04-19 Signal compression and expansion systems

Country Status (1)

Country Link
GB (1) GB1342383A (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0077266A1 (en) * 1981-10-09 1983-04-20 American Microsystems, Incorporated Switched capacitor automatic gain control loop
GB2116793A (en) * 1982-03-03 1983-09-28 Perkin Elmer Corp Variable gain amplifier
EP0114066A2 (en) * 1983-01-14 1984-07-25 Nec Corporation Automatic gain control circuit for burst signal communication system
US4471324A (en) * 1982-01-19 1984-09-11 Dbx, Inc. All NPN variably controlled amplifier
US4554508A (en) * 1983-12-07 1985-11-19 American Microsystems, Incorporated Carrier detection circuit
GB2171270A (en) * 1985-02-20 1986-08-20 Sgs Microelettronica Spa Low noise high thermal stability attenuator of the integratable type
GB2209444A (en) * 1987-07-21 1989-05-10 Plessey Co Plc An amplifier with improved dynamic range
WO2009029782A1 (en) * 2007-08-31 2009-03-05 Analog Devices, Inc. Variable automatic limit control (alc) threshold for any desired compression curve

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4441082A (en) * 1981-10-09 1984-04-03 American Microsystems, Inc. Switched capacitor automatic gain control loop
EP0077266A1 (en) * 1981-10-09 1983-04-20 American Microsystems, Incorporated Switched capacitor automatic gain control loop
US4471324A (en) * 1982-01-19 1984-09-11 Dbx, Inc. All NPN variably controlled amplifier
GB2116793A (en) * 1982-03-03 1983-09-28 Perkin Elmer Corp Variable gain amplifier
DE3307597A1 (en) * 1982-03-03 1983-10-20 The Perkin-Elmer Corp., 06856 Norwalk, Conn. AMPLIFIER WITH VARIABLE GAIN
EP0114066A3 (en) * 1983-01-14 1986-09-10 Nec Corporation Automatic gain control circuit for burst signal communication system
EP0114066A2 (en) * 1983-01-14 1984-07-25 Nec Corporation Automatic gain control circuit for burst signal communication system
US4554508A (en) * 1983-12-07 1985-11-19 American Microsystems, Incorporated Carrier detection circuit
GB2171270A (en) * 1985-02-20 1986-08-20 Sgs Microelettronica Spa Low noise high thermal stability attenuator of the integratable type
GB2171270B (en) * 1985-02-20 1989-07-26 Sgs Microelettronica Spa Low noise high thermal stability attenuator of the integratable type
GB2209444A (en) * 1987-07-21 1989-05-10 Plessey Co Plc An amplifier with improved dynamic range
US4924190A (en) * 1987-07-21 1990-05-08 Plessey Overseas Limited Amplifiers
GB2209444B (en) * 1987-07-21 1992-03-18 Plessey Co Plc Improvements in or relating to amplifiers
WO2009029782A1 (en) * 2007-08-31 2009-03-05 Analog Devices, Inc. Variable automatic limit control (alc) threshold for any desired compression curve
US7800440B2 (en) 2007-08-31 2010-09-21 Analog Devices, Inc. Variable automatic limit control (ALC) threshold for any desired compression curve
CN101790843B (en) * 2007-08-31 2012-12-26 美国亚德诺半导体公司 Variable automatic limit control (alc) threshold for any desired compression curve

Similar Documents

Publication Publication Date Title
ATE240607T1 (en) TRANSMITTERS FOR RADIO SIGNALS MODULATED WITH AN AUTOADAPTIVE AMPLIFIER POLARIZATION
CA2047870A1 (en) Automatic power control apparatus
CA2063403A1 (en) Gain/phase compensation for linear amplifier feedback loop
ES8306835A1 (en) A signal detection circuit with self-adjusting threshold having modulated carrier input.
GB1376059A (en) Amplifier circuit
GB1342383A (en) Signal compression and expansion systems
GB1036316A (en) Improvements in or relating to data transmission systems
GB1355160A (en) Data receiving circuit
GB1279508A (en) Transmission system
ES389517A1 (en) Coder-decoder for use in a delta-transmission system
GB1450989A (en) Analogue to digital converter
GB1084651A (en) Improvements in or relating to line communication systems
FR2437117B1 (en)
GB1412828A (en) Signal transmission systems
GB1432912A (en) Automatic frequency correcotr for a local oscillator
US2557950A (en) Pulse spacing modulated communication system
GB1513825A (en) Method of detecting alterations in signals corresponding to the read-out of a data carrier and system for implementing such a method
GB1323446A (en) Data communication system
GB1451546A (en) Signal-distortion correcting systems
GB1315115A (en) Wall-coverings
GB1234791A (en) Improvements in apparatus for distance measurement or control
SU557489A1 (en) Device for transmitting and receiving information
GB1490713A (en) Pulse code modulation data transmission systems
SU1649680A1 (en) Automatic device for controlling power of radio transmitter
GB1279757A (en) A device for converting amplitude samples of analogue signals into pulse code modulation signals

Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee