JPS642455A - Automatic level control circuit - Google Patents

Automatic level control circuit

Info

Publication number
JPS642455A
JPS642455A JP15808687A JP15808687A JPS642455A JP S642455 A JPS642455 A JP S642455A JP 15808687 A JP15808687 A JP 15808687A JP 15808687 A JP15808687 A JP 15808687A JP S642455 A JPS642455 A JP S642455A
Authority
JP
Japan
Prior art keywords
signal
level
pass filter
band
speech signal
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.)
Pending
Application number
JP15808687A
Other languages
Japanese (ja)
Other versions
JPH012455A (en
Inventor
Masatoshi Sekine
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.)
NEC Corp
Original Assignee
NEC Corp
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 NEC Corp filed Critical NEC Corp
Priority to JP15808687A priority Critical patent/JPS642455A/en
Publication of JPH012455A publication Critical patent/JPH012455A/en
Publication of JPS642455A publication Critical patent/JPS642455A/en
Pending legal-status Critical Current

Links

Landscapes

  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)

Abstract

PURPOSE: To suppress a noise level when a speech signal is not received by suppressing the gain of the control loop of an automatic level control amplifier to a level where a disconnection audible tone causes no problem when a received signal is only a noise.
CONSTITUTION: The input received signal is distributed to two systems. The system of an amplifier 1751, a band-pass filter 1752, a detector 1753, and a low-pass filter 1754 monitors the signal level of a frequency band wherein a speech signal has principal electric power as a voiced sound. Further, the system consisting of an amplifier 1755, a band-pass filter 1756, a detector 1758, and a low-pass filter 1758, on the other hand, monitors the signal level in a soundless section outside the speech signal band. The reference voltage output of a reference voltage generator 1761 has signal-to-noise power ratio set almost to a level where there is no problem when it is heard, and a comparator 1760 checks whether or not there is the speech signal.
COPYRIGHT: (C)1989,JPO&Japio
JP15808687A 1987-06-24 1987-06-24 Automatic level control circuit Pending JPS642455A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP15808687A JPS642455A (en) 1987-06-24 1987-06-24 Automatic level control circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP15808687A JPS642455A (en) 1987-06-24 1987-06-24 Automatic level control circuit

Publications (2)

Publication Number Publication Date
JPH012455A JPH012455A (en) 1989-01-06
JPS642455A true JPS642455A (en) 1989-01-06

Family

ID=15663994

Family Applications (1)

Application Number Title Priority Date Filing Date
JP15808687A Pending JPS642455A (en) 1987-06-24 1987-06-24 Automatic level control circuit

Country Status (1)

Country Link
JP (1) JPS642455A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06315173A (en) * 1993-04-30 1994-11-08 Iwatsu Electric Co Ltd Transmission controller
JP2012200001A (en) * 1997-11-04 2012-10-18 Nokia Corp Automatic gain control circuit

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06315173A (en) * 1993-04-30 1994-11-08 Iwatsu Electric Co Ltd Transmission controller
JP2012200001A (en) * 1997-11-04 2012-10-18 Nokia Corp Automatic gain control circuit

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