摘要:
PROBLEM TO BE SOLVED: To provide a PLL circuit equipped with a loop gain detecting circuit that can suppress the change of the loop gain. SOLUTION: When detecting the loop gain, the frequency of an input signal to a second input (IN-2) of a phase detector 101 is first changed, and the response corresponding to the change is detected by the output of a voltage controlled oscillator 102. The detection is performed by connecting the output of the voltage controlled oscillator 102 with a counter 103 and connecting the output of the counter 103 with an integrator 104. The phase locked loop characteristics are optimized by performing feedback for the detection result on the current value of the charge pump 105. COPYRIGHT: (C)2007,JPO&INPIT
摘要:
A digital signal processor generates in-phase, quadrature-phase and amplitude signals from a baseband signal. A modulator modulates the in-phase and quadrature-phase signals to produce a modulated signal. A phase locked loop is responsive to the modulated signal. The phase locked loop includes a controlled oscillator having a controlled oscillator input. An amplifier includes a signal input, amplitude control input and an output. The signal input is responsive to the controlled oscillator output and the amplitude control input is responsive to the amplitude signal. The phase locked loop that is responsive to the modulated signal includes a controlled oscillator output and a feedback loop between the controlled oscillator input and the controlled oscillator output. The feedback loop includes a mixer that is responsive to a local oscillator. The modulator may be placed in the phase locked loop. In particular, the modulator may be placed in the feedback loop between the controlled oscillator output and the mixer, between the local oscillator and the mixer, or between the mixer and the controlled oscillator input.
摘要:
PROBLEM TO BE SOLVED: To provide a communication system using a phase-locked loop employing two-point modulation.SOLUTION: A phase-locked loop 250 employing two-point modulation comprises: a master oscillator 100 having an output operably connected to a first input of a phase detector 106; a slave oscillator 102 having an output operably connected to a second input of the phase detector 106; and a forward-gain-adaptation module 200 operably connected to a raw-error terminal of the phase detector 106.
摘要:
PROBLEM TO BE SOLVED: To provide an FM modulator which can measure f-V characteristics of a voltage controlled oscillator (VCO) in a short time. SOLUTION: A characteristic measuring timing control section (110) informs a correcting section (108) of the starting timing and ending timing of the measurement of f-V characteristics of a VCO (103) in a transition process of a transmission wave frequency. Thus, the correcting section (108) can measure the f-V characteristics of the VCO (103) in a short time. COPYRIGHT: (C)2011,JPO&INPIT