Title:
時間的遅延の短い周波数比較装置
Document Type and Number:
Japanese Patent JP4294243
Kind Code:
B2
Abstract:
The device is in the form of a comparator block (CMP) comprises a phase/frequency comparator (PD) delivering a tuning signal (Tun) which is pulse-width modulated as a function of detected difference of the frequencies of two signals (Vdiv,Vref), a charge pump (CP) as a current source delivering a current (Ics) which is a function of the tuning signal, and a capacitor (Cs) for generating a control signal (Vcnt) by the capacitor charging with the current (Ics). The tuning signal has practically constant frequency and imposes the high-frequency variations to the control signal by the modulated pulse-width. The phase/frequency comparator (PD) contains an RS latch whose inputs for setting to logic 0 and 1 are controlled by the input signals via the active fronts detectrs, and whose output delivers the tuning signal; and a block for resetting the detectors. The active front of the first input signal (Vdiv) determines the leading edge of the tuning signal, and the active front of the second input signal (Vref) determines the trailing edge of the tuning signal. The frequency synthesizer comprises an oscillator (OSC) controlled by the signal (Vcnt), the comparator device (CMP), a programmable frequency divider (DIV) connected between the oscillator and the comparator device, and a quartz-crystal oscillator (XTAL) as the source of the reference-frequency signal (Vref). The apparatus for receiving radio-signals comprises an input stage in the form of antenna-filter block (AF) delivering the radio-frequency signl (Vfr), the frequency sythesizer delivering the local oscillator signal (Vlo), a mixer (MX) delivering the intermediate frequency signaal (Vfi), and a processing unit (PU). The method for controlling the frequency of a voltage-controlled oscillator includes the generation of tuning signal whose pulse-width is modulated as a function of the difference of frequencies of two signals, the use of tuning signal for controlling at least one current source, and the use of a voltage on a capacitor charged by the current source as the control signal.
Inventors:
David, Canal
Bangsan, Philator
Bangsan, Philator
Application Number:
JP2001361319A
Publication Date:
July 08, 2009
Filing Date:
November 27, 2001
Export Citation:
Assignee:
NXP B.V.
International Classes:
H03L7/089; H03D13/00; H03J5/02; H03L7/085; H03L7/093; H03L7/18; H04B1/26
Domestic Patent References:
| JP10290148A | ||||
| JP6090188A |
Attorney, Agent or Firm:
Kenji Yoshitake
Hidetoshi Tachibana
Takeshi Sekine
Takahashi
Hidetoshi Tachibana
Takeshi Sekine
Takahashi
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