Abstract:
본 발명은 위상 고정루프에서 루프 필터의 저항을 스위치드 커패시터 네트워크(switched-capacitor-network)로 대체한 경우에 있어서, 스위치드 커패시터 네트워크의 클럭을 전압 제어 발진기의 출력을 분주한 신호로 사용함으로써, 위상 고정 루프의 주파수에 반비례하도록 저항값을 바꾸어 주고, 특별한 구조 변화 없이 스위치드 커패시터 네트워크의 입력으로 들어가는 쪽의 분주 비율을 바꾸어 줌으로서 등가저항 값을 조정하는 구조를 제안한다.
Abstract:
A tunable on-chip oscillator is provided to facilitate trimming by only supplying of a reference signal with a reference frequency from the outside with a calibration code. A tunable on-chip oscillator includes a frequency comparator(111), a trimming code generator(112), an RC(Resistor-Capacitor) oscillator(12), a non-volatile memory(13), a first switch(14), and a second switch(15). The frequency comparator compares a frequency of an outer reference signal and that of an oscillation signal and outputs the comparison result. The trimming code generator generates a trimming code based on the comparison result and updates the trimming code until an optimal trimming code is obtained. The RC oscillator includes a plurality of resistors and a plurality of capacitors and generates an oscillation signal with an oscillation frequency represented by multiplication of the resistors and the capacitors. The non-volatile memory stores the optimal trimming code. The first switch transmits the trimming code from the trimming code generator to the RC oscillator. The second switch transmits the optimal trimming code from the non-volatile memory to the RC oscillator.
Abstract:
A method for measuring a gain of a VCO(Voltage Controlled Oscillator) and a frequency synthesizer are provided to decrease power consumption of the frequency synthesizer by stopping the operation of a measuring loop and a calibration unit at a normal mode. A frequency synthesizer includes an oscillator(240), a main loop(210), and a measuring loop(220). The oscillator generates an oscillation signal having a frequency corresponding to a magnitude of a control signal. The main loop is activated at a normal mode, and receives the oscillation signal. The main loop compares the oscillation signal with a first reference signal, generates the control signal according to the compared result, and provides the control signal to the oscillator. The measuring loop is activated at a measuring mode, and receives the oscillation signal. The measuring loop sequentially changes the frequency of the oscillation signal by a predetermined amount and provides the control signal to the oscillator according to the frequency of the oscillation signal.