What is PLL FM radio?
What is PLL FM radio?
For example, in a superheterodyne FM radio, a PLL is used to lock the local oscillator to an accurate frequency reference such as a crystal or ceramic resonator. It can also be used to demodulate the FM audio and stereo subcarrier signals from the intermediate frequency (IF) stage.
What is PLL and its applications?
PLLs are widely used in wireless or radio frequency (RF) applications, including Wi-Fi routers, broadcast radios, walkie-talkie radios, televisions and mobile phones. At its simplest, a phase-locked loop is a closed-loop feedback control circuit that’s both frequency- and phase-sensitive.
Why is PLL used?
The main purpose of a PLL circuit is to synchronize an output oscillator signal with a reference signal. When the phase difference between the two signals is zero, the system is “locked.” A PLL is a closed-loop system with a control mechanism to reduce any phase error that may occur.
What is PLL demodulation?
A phase-locked loop (PLL) is primarily used in tracking the phase and frequency of the carrier component of an incoming FM signal. PLL is also useful for synchronous demodulation of AM-SC (i.e., Amplitude Modulation with Suppressed carrier) signals or signals with few cycles of pilot carrier.
Why PLL method is popular for FM demodulation?
The PLL technology eliminates the costly RF transformers needed for circuits like the ratio FM detector and the Foster Seeley circuit. Typically a phase locked loop FM demodulator does not require the use of an inductor, let alone a transformer which is even more costly to manufacture.
What is the operating principle of PLL?
The input signal is directly proportional to the output frequency of the VCO (fo). The input and output frequencies are compared and adjusted through the feedback loop until the output frequency is equal to the input frequency. Hence, the PLL works like free running, capture, and phase lock.
How do you use PLL modulation demodulation?
To look at the operation of the PLL FM demodulator take the condition where no modulation is applied and the carrier is in the centre position of the pass-band the voltage on the tune line to the VCO is set to the mid position. However if the carrier deviates in frequency, the loop will try to keep the loop in lock.
Which characteristics of PLL is defined as the range of frequencies?
At what range the PLL can maintain the lock in the circuit? Explanation: The change in frequency of the incoming signal can be tracked when the PLL is locked. So, the range of frequencies over which PLL maintains the lock with the incoming signal is called as the lock in range. 7.
What are the three stages through which PLL operates?
Both the input frequency and output frequency are compared and adjusted through feedback loops until the output frequency equals the input frequency. Thus the PLL works in these stages – free-running, capture and phase lock.