PLL FM demodulator circuit

PLL FM demodulator. A simple PLL FM demodulator circuit using IC XR2212 is shown here. XR2212 is a highly stable, monolithic PLL (phase locked loop) IC specifically designed for communication and control system applications. The IC has 0.01 Hz to 300KHz frequency range, 4.5 to 20V operating voltage range, 2mV to 3Vrms dynamic range, high temperature range, TTL / CMOS compatibility and adjustable tracking range. The block diagram of a typical PLL FM demodulator circuit is shown below. The working of a PLL FM demodulator is very easy to understand.The input FM signal and the output of the VCO is…

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FSK Demodulator

PLL Application – FSK (Frequency Shift Keying) Demodulator FSK demodulator  using NE-SE 565 IC A very useful application of the 565 PLL is as a FSK demodulator. In the 565 PLL the frequency shift is usually accomplished by driving a VCO with the binary data signal so that the two resulting frequencies corre­spond to the logic 0 and logic 1 states of the binary data signal. The frequencies corresponding to logic 1 and logic 0 states are commonly called the mark and space frequencies. Several standards are used to set the mark and space frequencies. An FSK signal demodulator can…

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Frequency Demodulation

PLL Application – Frequency Demodulation Using NE-SE 565 IC Frequency demodulation or detection can be obtained directly by using the PLL circuit. When the centre frequency of the PLL is selected or designed at the FM carrier frequency, the filtered or output voltage in the circuit shown in figure, is obviously the desired demodulated voltage, that varies in magnitude in proportion to the signal frequency. The PLL circuit thus can be operated as complete IF strip, limiter, and detector as employed in FM receivers. The 565, very popular PLL unit, containing a phase comparator PC, amplifier, and VCO, is shown in…

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Frequency Multiplication

PLL Applications 1. Frequency Multiplication or Frequency Synthesis The block diagram of a frequency muliplier (or synthesizer) is shown in figure. In this circuit, a frequency divider is inserted between the output of the VCO and the phase comparator (PC) so that the loop signal to the PC is at frequency fOUT while the output of VCO is N fOUT. This output is a multiple of the input frequency as long as the loop is in lock. The desired amount of multiplication can be obtained by selecting a proper divide- by N network where N is an integer. Figure shows…

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PLL Operation

How a PLL works ? Consider VCO operating without input signal at free-running frequency fr and input signal of frequency fIN increasing from zero is applied to the PC. If the input frequency is less than fIN1, then the error voltage Ve is zero as illustrated in figure and VCO operates at a frequency fr. When the input signal frequency fIN reaches a frequency fin1 (the lower edge of the capture range), then the output or error voltage Ve jumps from zero to some negative voltage with beat notes of frequency (difference between input signal frequency and actual VCO output…

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Phase Locked Loop IC’s

MONOLITHIC PHASE-LOCKED LOOP (PLL) ICS Although the evolution of the PLL began in the early 1930s but its cost outweighted its advantage in the beginning. Today the PLL is even available as a single package, typical examples of which are the Signetic’s SE/NE series such as 560, 561, 562, 564, 565 and 567. They only differ in operating frequency range, power requirements, and frequency and bandwidth (BW) adjustment ranges. SE/NE 565 is the most widely employed IC of the series. The device is available as a 14-pin DIP package  and as a 10-pin metal can package. Its important electrical characteristics…

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PLL Operating Principle

Operating principle of Phase Locked Loops The block diagram showing operating principle of PLLis given in figure. As illustrated in this fig, the PLL consists of a phase detector, a low-pass filter and a voltage controlled oscillator. YOU MAY ALSO REFER: PHASE LOCKED LOOP IC’s, DESIGN A PLL, PLL OPERATION, and PLL FM DEMODUATOR CIRCUIT Phase Detector A phase detector is basically a comparator that compares the input frequency fin with feedback frequency fout. The phase detector receives two digital signals, one from the input, the other feedback from the output. The loop is locked when these two signals are of the same frequency…

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PLL-Phase Locked Loops

Phase Locked Loops (PLL) Introduction to PLL The concept of Phase Locked Loops (PLL) first emerged in the early 1930’s.But the technology was not developed as it now, the cost factor for developing this technology was very high. Since the advancement in the field of integrated circuits, PLL has become one of the main building blocks in the electronics technology. In present, the PLL is available as a single IC in the SE/NE560 series (560, 561, 562, 564, 565 and 567) to further reduce the buying cost ,the discrete IC’s are used to construct a PLL. PLL Applications Frequency Modulation…

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