JPS5648709A - Local oscillating circuit of fm receiver - Google Patents

Local oscillating circuit of fm receiver

Info

Publication number
JPS5648709A
JPS5648709A JP12379879A JP12379879A JPS5648709A JP S5648709 A JPS5648709 A JP S5648709A JP 12379879 A JP12379879 A JP 12379879A JP 12379879 A JP12379879 A JP 12379879A JP S5648709 A JPS5648709 A JP S5648709A
Authority
JP
Japan
Prior art keywords
varicap
voltage
control
capacitor
coil
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
JP12379879A
Other languages
Japanese (ja)
Other versions
JPS6243573B2 (en
Inventor
Yoshihiko Watanabe
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.)
Pioneer Corp
Original Assignee
Pioneer Electronic 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 Pioneer Electronic Corp filed Critical Pioneer Electronic Corp
Priority to JP12379879A priority Critical patent/JPS5648709A/en
Publication of JPS5648709A publication Critical patent/JPS5648709A/en
Publication of JPS6243573B2 publication Critical patent/JPS6243573B2/ja
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J3/00—Continuous tuning
    • H03J3/02—Details
    • H03J3/16—Tuning without displacement of reactive element, e.g. by varying permeability
    • H03J3/18—Tuning without displacement of reactive element, e.g. by varying permeability by discharge tube or semiconductor device simulating variable reactance
    • H03J3/185—Tuning without displacement of reactive element, e.g. by varying permeability by discharge tube or semiconductor device simulating variable reactance with varactors, i.e. voltage variable reactive diodes

Landscapes

  • Noise Elimination (AREA)

Abstract

PURPOSE:To improves S/N by preventing the capacitor of a varicap from varying with an AC component of a hum, etc., superposed upon a control DC voltage, by applying the AC component to both terminals of the varicap in phase. CONSTITUTION:Resistance R3, grounded while connected in series to varicap D, has its value set sufficiently large and sufficiently small for the impednace of varicap D and control DC voltage V is all applied to varicap D. Further, capacitor C3 and coil L2 both have low impedance values. Thus, control DC voltage V is applied to varicap D via resistance R2 and coil L2 to vary the capacity. Since capacitor C3 and coil L2 provide low impedance and resistance R3 high impedance, an AC component of a hum superposed upon this voltage is applied across varicap D in phase, and consequently a difference in potential across varicap D disappears, so that varicap D will vary in capacity only with control DC voltage V.
JP12379879A 1979-09-28 1979-09-28 Local oscillating circuit of fm receiver Granted JPS5648709A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP12379879A JPS5648709A (en) 1979-09-28 1979-09-28 Local oscillating circuit of fm receiver

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP12379879A JPS5648709A (en) 1979-09-28 1979-09-28 Local oscillating circuit of fm receiver

Publications (2)

Publication Number Publication Date
JPS5648709A true JPS5648709A (en) 1981-05-02
JPS6243573B2 JPS6243573B2 (en) 1987-09-16

Family

ID=14869567

Family Applications (1)

Application Number Title Priority Date Filing Date
JP12379879A Granted JPS5648709A (en) 1979-09-28 1979-09-28 Local oscillating circuit of fm receiver

Country Status (1)

Country Link
JP (1) JPS5648709A (en)

Also Published As

Publication number Publication date
JPS6243573B2 (en) 1987-09-16

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