JPS5754435A - Automatic squelch controlling system - Google Patents

Automatic squelch controlling system

Info

Publication number
JPS5754435A
JPS5754435A JP12910680A JP12910680A JPS5754435A JP S5754435 A JPS5754435 A JP S5754435A JP 12910680 A JP12910680 A JP 12910680A JP 12910680 A JP12910680 A JP 12910680A JP S5754435 A JPS5754435 A JP S5754435A
Authority
JP
Japan
Prior art keywords
noise
voltage
comparator
amplified
received
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
JP12910680A
Other languages
Japanese (ja)
Inventor
Takehiko Takahashi
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.)
KOORARU KK
Original Assignee
KOORARU KK
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 KOORARU KK filed Critical KOORARU KK
Priority to JP12910680A priority Critical patent/JPS5754435A/en
Publication of JPS5754435A publication Critical patent/JPS5754435A/en
Pending legal-status Critical Current

Links

Classifications

    • 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
    • H03G3/34—Muting amplifier when no signal is present or when only weak signals are present, or caused by the presence of noise signals, e.g. squelch systems
    • H03G3/344—Muting responsive to the amount of noise (noise squelch)

Landscapes

  • Control Of Amplification And Gain Control (AREA)
  • Noise Elimination (AREA)

Abstract

PURPOSE:To make troublesome adjusting operation unnecessary, by keeping the state of squelch-on when only noise is received, and opening the squelch when a signal over an average level of external noise is received. CONSTITUTION:A part of an audio frequency signal is applied to an HOH30, and only high frequency components are picked up out of it, they are amplified at a noise amplifier 31 and rectified at a diode 32. This rectifying voltage is amplified 33 and applied to a noninverting input terminal + of a voltage comparator 34. On the other hand, an AGC voltage is applied to an inverting input terminal - of a comparator 34 to compare the inputs at both terminals. When only noise is received, since a voltage applied to a terminal + is higher, the output voltage of the comparator 34 is higher and the gain of a low frequency amplifier 26 is lowered. Thus, a noise voltage applied through a variable resistor 25 is not amplified and no noise is produced from a speaker 28. If a signal having a level over an average level of noise comes, the output voltage of the comparator 34 decreases the gain of an amplifier 26 is increased.
JP12910680A 1980-09-19 1980-09-19 Automatic squelch controlling system Pending JPS5754435A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP12910680A JPS5754435A (en) 1980-09-19 1980-09-19 Automatic squelch controlling system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP12910680A JPS5754435A (en) 1980-09-19 1980-09-19 Automatic squelch controlling system

Publications (1)

Publication Number Publication Date
JPS5754435A true JPS5754435A (en) 1982-03-31

Family

ID=15001213

Family Applications (1)

Application Number Title Priority Date Filing Date
JP12910680A Pending JPS5754435A (en) 1980-09-19 1980-09-19 Automatic squelch controlling system

Country Status (1)

Country Link
JP (1) JPS5754435A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02123138U (en) * 1989-03-20 1990-10-09
CN113824470A (en) * 2021-09-26 2021-12-21 海南宝通实业公司 Method and device for improving frequency hopping receiving voice quality

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02123138U (en) * 1989-03-20 1990-10-09
CN113824470A (en) * 2021-09-26 2021-12-21 海南宝通实业公司 Method and device for improving frequency hopping receiving voice quality

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