Analog multipler , vco and pll -PPT.pptx

It's is the portion of analog multipler and pll

1. Unit - 3 ANALOG MULTPLIER AND PLL: Analog Multiplier using Emitter Coupled Transistor pair, Gilbert Multiplier cell, Operation of the basic PLL, closed loop analysis, Voltage controlled oscillator, application of PLL for AM detection, FM detection, FSK modulator and demodulator, Frequency synthesizers.

2. INTRODUCTION

3. INTRODUCTION

4. The Emitter-Coupled Pair as a Simple Multiplier

5. TWO QUADRANT RESTRICTION

6. Gilbert multiplier cell

7. Gilbert multiplier cell Applications

8. Phase-Locked Loop (PLL) 10

9. OBJECTIVES Introduction to Phase-locked loop (PLL) Basic PLL System Phase Detector (PD) Voltage Controlled Oscillator (VCO) Loop Filter (LF) PLL Applications 11

10. A Phase-Locked Loop (PLL) is a negative feedback system consists of a phase detector , a low pass filter and a voltage controlled oscillator (VCO) within its loop. Its purpose is to synchronize an output signal with a reference or input signal in frequency as well as in phase. In the synchronized or “locked” state, the phase error between the oscillator’s output signal and the reference signal is zero, or it remains constant. If a phase error builds up, a control mechanism acts on the oscillator to reduce the phase error to a minimum so that the phase of the output signal is actually locked to the phase of the reference signal. This is why it is called a PLL. Introduction to Phase-locked Loop (PLL) 12

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13. 15 There are three stages of PLL operations : Free Running Stage: When no input is applied at the phase detector, PLL out put frequency is f osc = f o where f o free running frequency of the VCO. Capture Stage: When an input is applied at the phase detector and due to feedback mechanism PLL tries to track the output with respect to the input. Phase Locked Stage: Due to feedback mechanism, the frequency comparison stops when f osc = f in .

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28. 30 FSK DEMODULATOR

29. 31 FREQUENCY MULTIPLIER