What is PLL tuning?

What is PLL tuning?

A phase-locked loop or phase lock loop (PLL) is a control system that generates an output signal whose phase is related to the phase of an input signal. There are several different types; the simplest is an electronic circuit consisting of a variable frequency oscillator and a phase detector in a feedback loop.

Why is PLL used?

The PLL is widely used for a variety of purposes. It is used to recover the clock signal in some wireless applications. It is used to recover the original signal in frequency modulation radio. It is used to multiply a frequency by a fixed factor.

Why PLL is used in microcontroller?

PLLs are finding increasing usage in microcontrollers to manipulate the frequency of clock signals. This can allow certain sections of the microcontroller to run faster than others, or to run the microcontroller at a clock frequency faster than the oscillator itself.

What is FM PLL?

PLL permits the tracking of frequency changes of the input signals with the self-correction ability of the system and lock the signal at particular frequency. The Frequency Modulated (FM) signal is considered as a series of numerical values or digital data.

What are the different stages of PLL?

Thus, a PLL goes through three stages (i) free running, (ii) capture and (iii) locked or tracking. Capture range: the range of frequencies over which the PLL can acquire lock with an input signal is called the capture range.

What is PLL block diagram?

PLL Block Diagram It is basically a flip flop consisting of a phase detector, a low pass filter (LPF),and a Voltage Controlled Oscillator (VCO). Block Diagram – Phase Locked Loops. The input signal Vi with an input frequency fi is passed through a phase detector.

How is FM signal generated?

FM signals can be generated either by using direct frequency modulation, which is achieved by inputting a message directly into a voltage-controlled oscillator, or by using indirect frequency modulation, which is achieved by integrating a message signal to generate a phase-modulated signal, which is then used to ...

What are 3 running conditions in PLL?

Thus, a PLL goes through three stages (i) free running, (ii) capture and (iii) locked or tracking.

Is the phase detector in a PLL analog or digital?

• Analogue or digital in PLL design. In a digital PLL, however, the phase detector’s output is a digital number proportional to the time difference between the edges of the incoming reference signal and the feedback signal. These digital words are sent to the digital loop filter, which filters the phase detector output.

Can a digital PLL be used with an analogue PLL?

• To overcome the limitations of either PLL design, it is possible to combine a digital PLL followed by an analogue PLL. The digital PLL can handle clock switching and difficult frequency ratios, while the analogue one can be used to further attenuate spurs, multiply to higher frequencies, and perform clock distribution.

What's the difference between PLL and PLL based synthesizers?

• Furthermore, the output of these devices is phase-continuous during the transition to the new frequency. In contrast, the basic PLL-based analog synthesizer typically has an output tuning resolution of 1 kilohertz; it lacks the inherent resolution afforded by the digital signal processing.

How long is the output frequency switching time of an analog PLL?

• Output-frequency switching time: the analog PLL frequency switching time is a function of its feedback loop settling time and VCO response time, typically > 1 ms. C-DDS-based synthesizer switching time is limited only by DDS digital processing delay; the AD9850's minimum output frequency switching time is 43 ns.