The VCO is a special type of oscillator that has a frequency controlled by an applied voltage.
The frequency of the VCO without any control signal applied is called the free running frequency.
You typically create a DC power supply from the low frequency, and use that to run a high frequency oscillator and amplifier. If there needs to be a relationship between frequency in and frequency out, often there is a divider running on the high frequency side in combination with a phase locked loop synching up to the low frequency side.
The output of the voltage-controlled oscillator (VCO) in a phase-locked loop (PLL) circuit is a periodic waveform, typically a sine or square wave, whose frequency is controlled by the input voltage. This voltage is derived from the phase comparator in the PLL, which adjusts the VCO frequency to match the frequency of a reference signal. As the PLL locks onto the reference signal, the VCO output frequency stabilizes, ensuring that it is phase-locked with the reference. This output can be used for various applications, including frequency synthesis and modulation.
Lock Range of a PLL is the range of frequencies centered at free running frequency of VCO, around which the PLL can remain in locked state. Capture Range of a PLL is the range of frequencies centered at free running frequency of VCO, around which the PLL can acquire lock-in from an unlocked state. The relation is Capture Range<=Lock Range
To use the PLL (Phase Lock Loop) as FM detector, you need to know the Free-running frequency.
Single phase and three phase voltages are not related to the frequency at which the voltage is generated. The frequency at which voltages are generated is governed by the speed of rotation of the generating device.
The zero phase frequency is the frequency at which the phase of the input signal and the output signal match.
You typically create a DC power supply from the low frequency, and use that to run a high frequency oscillator and amplifier. If there needs to be a relationship between frequency in and frequency out, often there is a divider running on the high frequency side in combination with a phase locked loop synching up to the low frequency side.
The output of the voltage-controlled oscillator (VCO) in a phase-locked loop (PLL) circuit is a periodic waveform, typically a sine or square wave, whose frequency is controlled by the input voltage. This voltage is derived from the phase comparator in the PLL, which adjusts the VCO frequency to match the frequency of a reference signal. As the PLL locks onto the reference signal, the VCO output frequency stabilizes, ensuring that it is phase-locked with the reference. This output can be used for various applications, including frequency synthesis and modulation.
One method to extract the intelligence (signal) from a high frequency carrier in FM receivers is with a phase locked loop.
One way of using a flip flop as a frequency doubler is to create an oscillator at the desired doubled frequency, and then divide by two with the flip flop, resulting in the original frequency, and then controlling the oscillator with a phase locked loop.
A phase-locked loop (PLL) can be used as a universal detector for Amplitude Modulation (AM) by utilizing its ability to track the phase and frequency of the incoming modulated signal. The PLL locks onto the carrier frequency of the AM signal, allowing it to demodulate the envelope variations caused by the modulation. By comparing the output of the PLL with the original carrier frequency, the modulation information can be extracted as the difference between the two signals. This makes the PLL an effective detector for demodulating AM signals across a wide range of frequencies and modulation depths.
Lock Range of a PLL is the range of frequencies centered at free running frequency of VCO, around which the PLL can remain in locked state. Capture Range of a PLL is the range of frequencies centered at free running frequency of VCO, around which the PLL can acquire lock-in from an unlocked state. The relation is Capture Range<=Lock Range
The difference between frequency modulation and phase modulation is that with frequency modulation the angular frequency of the signal is modified while with the phase modulation, the phase angle of the signal is modified.
Phase modulation and frequency modulation are related because changes in the phase of a signal result in corresponding changes in its frequency. When the phase of a signal is modulated, it causes variations in the frequency of the signal as well. Therefore, in practice, it is difficult to separate phase modulation from frequency modulation, especially in communication systems where both aspects are interconnected.
To use the PLL (Phase Lock Loop) as FM detector, you need to know the Free-running frequency.
Single phase and three phase voltages are not related to the frequency at which the voltage is generated. The frequency at which voltages are generated is governed by the speed of rotation of the generating device.
James P. Maligeorgos has written: 'A 3.8-6.4GHz local oscillator system using an injection-locked frequency doubling and phase tuning technique'