A mechanical analog of this device consists of two weels on a shaft coupled to each other through a 
A mechanical analog of this device consists of two weels on a shaft coupled to each other through a spring wound around the shaft, with external torque playing the part of voltage. One part of this device is a special type of comparator, sometimes constructed in digital ones with XOR gates. When not receiving input, the voltage-controlled oscillator that is part of this device will operate at the free-running frequency, and its capture range dictates the limits of this device's ability to acquire a frequency due to the low-pass filter that is usually at its input. Capable of modulation, demodulation, and signal generation, FTP, identify this electronic feedback circuit which produces an output frequency to match the frequency of its input.
A mechanical analog of this device consists of two weels on a shaft coupled to each other through a spring wound around the shaft, with external torque playing the part of voltage.
phase-locked loop