JPS57143951A - Stereophonic demodulator - Google Patents

Stereophonic demodulator

Info

Publication number
JPS57143951A
JPS57143951A JP2845781A JP2845781A JPS57143951A JP S57143951 A JPS57143951 A JP S57143951A JP 2845781 A JP2845781 A JP 2845781A JP 2845781 A JP2845781 A JP 2845781A JP S57143951 A JPS57143951 A JP S57143951A
Authority
JP
Japan
Prior art keywords
signal
frequency
inputted
frequency divider
demodulator
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
JP2845781A
Other languages
Japanese (ja)
Inventor
Yoshimi Iso
Masanori Ienaka
Shigeki Inoue
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.)
Hitachi Ltd
Original Assignee
Hitachi 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 Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP2845781A priority Critical patent/JPS57143951A/en
Publication of JPS57143951A publication Critical patent/JPS57143951A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H40/00—Arrangements specially adapted for receiving broadcast information
    • H04H40/18—Arrangements characterised by circuits or components specially adapted for receiving
    • H04H40/27—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95
    • H04H40/36—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for stereophonic broadcast receiving
    • H04H40/45—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for stereophonic broadcast receiving for FM stereophonic broadcast systems receiving
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D1/00—Demodulation of amplitude-modulated oscillations
    • H03D1/22—Homodyne or synchrodyne circuits
    • H03D1/2209—Decoders for simultaneous demodulation and decoding of signals composed of a sum-signal and a suppressed carrier, amplitude modulated by a difference signal, e.g. stereocoders
    • H03D1/2236—Decoders for simultaneous demodulation and decoding of signals composed of a sum-signal and a suppressed carrier, amplitude modulated by a difference signal, e.g. stereocoders using a phase locked loop
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H40/00—Arrangements specially adapted for receiving broadcast information
    • H04H40/18—Arrangements characterised by circuits or components specially adapted for receiving
    • H04H40/27—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95
    • H04H40/36—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for stereophonic broadcast receiving
    • H04H40/45—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for stereophonic broadcast receiving for FM stereophonic broadcast systems receiving
    • H04H40/72—Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for stereophonic broadcast receiving for FM stereophonic broadcast systems receiving for noise suppression

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Stereo-Broadcasting Methods (AREA)

Abstract

PURPOSE:To stabilize the operation of a demodulator by improving its SCA signal elimination ratio, by canceling each other an SCA signal and an unnecessary signal included in a composite signal, and a beat signal brought out by higher harmonics of a subcarrier frequency. CONSTITUTION:The oscillation frequency of the VCO7 of a PLL type stereophonic demodulator is set N times as high as a subcarrier frequency, and then divided by frequency dividers 101 and 102 to the subcarrier frequency, and the result is further divided by a frequency divider 9 and inputted to a phase comparator 4. The output of the frequency divider 102 is supplied to a waveform shaping circuit 104 to generate a sampling signal with short pulse width, which is switched as prescribed by switching circuits 106 and 108 and held by holding amplifier 110 and 112, whose outputs are inputted to mixers 113 and 114. The output of the frequency divider 101 is multiplied by a composite signal through analog multiplying circuits 105 and 107, and the resulting signals are inputted through LPFs 109 and 111 to the mixers 113 and 114; and the outputs of the LPFs and those of the amplifiers 110 and 112 are operated by gain adjustment, thus canceling beats.
JP2845781A 1981-03-02 1981-03-02 Stereophonic demodulator Pending JPS57143951A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2845781A JPS57143951A (en) 1981-03-02 1981-03-02 Stereophonic demodulator

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2845781A JPS57143951A (en) 1981-03-02 1981-03-02 Stereophonic demodulator

Publications (1)

Publication Number Publication Date
JPS57143951A true JPS57143951A (en) 1982-09-06

Family

ID=12249188

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2845781A Pending JPS57143951A (en) 1981-03-02 1981-03-02 Stereophonic demodulator

Country Status (1)

Country Link
JP (1) JPS57143951A (en)

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