JPS57175964A - Frequency detector - Google Patents

Frequency detector

Info

Publication number
JPS57175964A
JPS57175964A JP6137381A JP6137381A JPS57175964A JP S57175964 A JPS57175964 A JP S57175964A JP 6137381 A JP6137381 A JP 6137381A JP 6137381 A JP6137381 A JP 6137381A JP S57175964 A JPS57175964 A JP S57175964A
Authority
JP
Japan
Prior art keywords
input
output
pulse
flip flop
frequency
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
JP6137381A
Other languages
Japanese (ja)
Inventor
Seiya Matsuzawa
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.)
Toshiba Corp
Original Assignee
Toshiba Corp
Tokyo Shibaura Electric 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 Toshiba Corp, Tokyo Shibaura Electric Co Ltd filed Critical Toshiba Corp
Priority to JP6137381A priority Critical patent/JPS57175964A/en
Publication of JPS57175964A publication Critical patent/JPS57175964A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
    • G01R23/02—Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage
    • G01R23/15—Indicating that frequency of pulses is either above or below a predetermined value or within or outside a predetermined range of values, by making use of non-linear or digital elements (indicating that pulse width is above or below a certain limit)

Landscapes

  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Electronic Switches (AREA)

Abstract

PURPOSE:To widely reduce a ripple voltage in the proximity of a reference frequency and to enable improving of an answering frequency, by a method wherein a phase of an output of a flip flop, frequency-dividing an input frequency, is compared with that of an output of a pulse generating circuit. CONSTITUTION:An input voltage wave from is inputted to a pulse generating circuit 1, and a pulse, generated at a zero intersecting point where it changes from a negative to a positive, is inputted to a flip flop 2. A pulse generating circuit 3 generates a pulse for a sepcified period T0 at rise of the output of the flip flop 2, and said pulse and the output of the flip flop 2 are inputted to a phase comparing circuit 4. In the phase comparing circuit 4, in case an input A is a ''1'' and an input B is a ''0'', an output terminal D goes to a ''1'', and in case the input A is a ''0'' and the input B is a ''1'', an output terminal C attains a ''1'' to actuate switches 5 and 6, respectively. The switches 5 and 6 feed a pulse current (i) from reference voltages -VR and VR to an operational amplifier OA, of which a low-pass filter consists, via resistors R1, and outputs a DC output voltage e0.
JP6137381A 1981-04-24 1981-04-24 Frequency detector Pending JPS57175964A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6137381A JPS57175964A (en) 1981-04-24 1981-04-24 Frequency detector

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6137381A JPS57175964A (en) 1981-04-24 1981-04-24 Frequency detector

Publications (1)

Publication Number Publication Date
JPS57175964A true JPS57175964A (en) 1982-10-29

Family

ID=13169303

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6137381A Pending JPS57175964A (en) 1981-04-24 1981-04-24 Frequency detector

Country Status (1)

Country Link
JP (1) JPS57175964A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0142171A2 (en) 1983-11-17 1985-05-22 Kabushiki Kaisha Toshiba Frequency comparing circuit
CN103575979A (en) * 2012-07-26 2014-02-12 南京邮电大学 Method for digital measuring of alternating current frequency

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS50147373A (en) * 1974-05-16 1975-11-26
JPS5222967A (en) * 1975-08-14 1977-02-21 Nippon Columbia Co Ltd Time differential generation circuit for the width of a pulse

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS50147373A (en) * 1974-05-16 1975-11-26
JPS5222967A (en) * 1975-08-14 1977-02-21 Nippon Columbia Co Ltd Time differential generation circuit for the width of a pulse

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0142171A2 (en) 1983-11-17 1985-05-22 Kabushiki Kaisha Toshiba Frequency comparing circuit
US4599580A (en) * 1983-11-17 1986-07-08 Kabushiki Kaisha Toshiba Circuit for comparing two or more frequencies
EP0308540A2 (en) * 1983-11-17 1989-03-29 Kabushiki Kaisha Toshiba Oscillator circuit
CN103575979A (en) * 2012-07-26 2014-02-12 南京邮电大学 Method for digital measuring of alternating current frequency

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