Phase locked loops ( 8 ) :

Phase locked loop (PLL) is a system which consists of a voltagecontrolled oscillator, phase comparator and feedback circuit.PLL it's basic form takes in a reference frequency and triesto output the same frequency out (with a known phase shift).With a feedback circuit which contains a frequency dividerit is possible to generate output frequencies which are N timesthe input frequency.

• Inverting latches make simple VCO - simple VCO circuit which is synthesized from inverting latch stages and is tunable to an integer multiple of the input frequency by selecting which output phases feed back to the input multiplexer, suitable to be usable as on-chip clock multiplication in ASICs   
• Low-cost circuit biases VCOs for cable and TV - PLLs are useful in a variety of applications, most notably cable and TV tuners   
• Selecting passive components for PLLs - PLLs in SERDES circuits typically require external resistors and capacitors. Other PLLs, such as cleanup circuits with high-Q VCXOs, also use external components. Theory and practical experimentation combine to enable you to optimize these components' values, minimizing jitter.   
• Software PLL locks VCXO to reference - provides a precisely controlled clock signal using voltage controlled crystal oscillator controlled by microcontroller   
• Straightforward techniques cut jitter in PLL-based clock drivers - this article describes jitter and its causes and effects and shows you how to reduce it   
• Synchronous oscillator outperforms the PLL - PLL has numerous limitations, including low input-signal sensitivity and contradictory design requirements, synchronous oscillator doesn't suffer from these problems and has many powerful properties   
• Technique eases design of high-order PLLs - maintaining stability in high-order PLLs can be a chore unless you know exactly what you are doing   
• Understanding VCO Concepts   

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