JPS6416086A - Demodulation circuit - Google Patents

Demodulation circuit

Info

Publication number
JPS6416086A
JPS6416086A JP17215487A JP17215487A JPS6416086A JP S6416086 A JPS6416086 A JP S6416086A JP 17215487 A JP17215487 A JP 17215487A JP 17215487 A JP17215487 A JP 17215487A JP S6416086 A JPS6416086 A JP S6416086A
Authority
JP
Japan
Prior art keywords
sap
electric field
constant current
weak electric
circuit
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.)
Granted
Application number
JP17215487A
Other languages
Japanese (ja)
Other versions
JPH0638653B2 (en
Inventor
Yoshinori Mitsumata
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 IC Microcomputer Systems Co Ltd
Original Assignee
NEC IC Microcomputer Systems 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 NEC IC Microcomputer Systems Co Ltd filed Critical NEC IC Microcomputer Systems Co Ltd
Priority to JP17215487A priority Critical patent/JPH0638653B2/en
Publication of JPS6416086A publication Critical patent/JPS6416086A/en
Publication of JPH0638653B2 publication Critical patent/JPH0638653B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Abstract

PURPOSE:To improve the S/N of a SAP demodulation signal (voice signal) at a weak electric field by operating a constant current switching circuit to narrow the band width of the SAP filter at a weak electric field. CONSTITUTION:An output signal of a comparator circuit 9 at a weak electric field switches a constant current of a constant current changeover circuit 10 to increase the mutual conductance gm of a differential amplifier circuit constituting a SAP filter of gyrator structure thereby narrowing the band width of the SAP filter 2. That is, the current of the differential amplifiers 14, 15 is increased by the constant current switching circuit 10 at a weak field to narrow the band width of the SAP filter. Thus, noise at the side band of the SAP modulation signal inputted to the FM detection circuit 3 is reduced to improve the S/N of the SAP demodulation signal at weak electric field.
JP17215487A 1987-07-09 1987-07-09 Demodulation circuit Expired - Lifetime JPH0638653B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP17215487A JPH0638653B2 (en) 1987-07-09 1987-07-09 Demodulation circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP17215487A JPH0638653B2 (en) 1987-07-09 1987-07-09 Demodulation circuit

Publications (2)

Publication Number Publication Date
JPS6416086A true JPS6416086A (en) 1989-01-19
JPH0638653B2 JPH0638653B2 (en) 1994-05-18

Family

ID=15936567

Family Applications (1)

Application Number Title Priority Date Filing Date
JP17215487A Expired - Lifetime JPH0638653B2 (en) 1987-07-09 1987-07-09 Demodulation circuit

Country Status (1)

Country Link
JP (1) JPH0638653B2 (en)

Also Published As

Publication number Publication date
JPH0638653B2 (en) 1994-05-18

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