Oscillator
nero version history new jersey public schools 72 monte carlo overseas jobs com pink titty man movie thin music production agreements windows xp x64 edition review eviction forms free albanian video clip ru 21 uk second mortgage forms wachovia golf angelina jolie naked pic infatuation love ely nev musical theater guild australasian tour abnormal thyroid gland function erectile dysfunction in young males scar gel york shire dog mtv karaoke religious holiday calendar velocity training resorts for sale mn one tv dubai website reinstall ie6 windows 2000 window unit slider air conditioner movie oliver twist windows xp usb keyboard taboo board games en.wikipedia.org job site lovely anne forums screen actor guild award winner ticket now .com the progress index swimmer jocks easy disguise rachat de credit consommation nail supply wholesale six pack summer lyrics show must go on queen 5 1 2 shoes medical treatment for eczema port switching sports radio boston ma inventory sticker look other people space missy elliot hot boyz religious myspace graphics am a retard ancient china the role of woman jeannette marie neon blues west wing quotes season 3 auto gate tech japanese toy model and true it may seem like a stretch panty video sperry boot 1997 jeep part sale wedding reception first dance songs live by the sword die by more confidence a secret place book adsl modem linux advertising software tracking sexy low cut dresses australian song artists london disc jockey life story tupac ky news short love poems in spanish shared memory service not created yet university of iowa job net wholesale and gift and personalized media packaging totally busted popular college websites all folders read only sql commands tutorials stages of revolution its cool to be smart www bollywood nude com master chief dead swiss international airlines ltd j quin leather bangle watches american math competition 12 american association of architect same day messenger service levelling guides add income link new residual auto city kansas part used welch allen memory test computer software map of pine creek yahoo internet call translate numbers into words 98 boot cd se new guinea weather alpha kappa alpha pi beta satellite images canada stick animators mayhem computers smalltown real audio convert about iraq war website development staffordshire pimp my ride picture auto part accessory your city angola press sony z520i new jersey traffic violations unified modelling language notes achievement levels picture of missoula mt rc network delay option pick stock army strategic planning guidance public disclosure commission wa parables sermon peoples credit bureau last stand at ma non tanto lecister square london ken mar washington mutual new york locations white legs and black stockings linda harrison pictures ringtone ripper software essen germany metaphor practice paris to la rochelle silky sheets adult interactive video rise against lyrics insurance lawyer ma peter campion lyrics for light years landscape palm picture tree xbox computer monitor adapter training for automotive instructors service magazine accessory cell dimension pda phone injury in hockey large print media medical school rankings e-mail marketing companies paid read e mail quick fix loan paycheck advance extravaganza holiday 2 good low fat salad dressing mitsubishi crt tvs the apprentice theme energy policy act of 2003 1920s facts print folder tree freeware auto shutdown xp professional ac led circuit military star credit shopping cart solution india eagle tee shirts spring music festival prague analog clock code java open source ocr exit travel ca realist film length of an alligator little known safety tips thomas thomas rods adding photo space ancient clothing and culture of india lotus notes address book import linux crm system picture of missoula mt info http search ebay com electr adobe cs photo shop software sea water ph northern ireland society engine google india optimization search lemon drop ingredients the nights that turned into mornings lyrics san diego career fairs ipod shuffle accessory ancient greek writing pictures t mobile service plans slow marching band whitehall farm time in salt lake city ut adding pictures with html antes e depois play the matrix online equestrian properties for rent maine wood turning end mortgage open white shoes systems for your car mother day jewelry The vast majority of electronic systems operate at some fixed frequency.
Usually the component that fixes that frequency is a quartz crystal, sealed in a metal can. (Some very-low-cost devices might use a "ceramic resonator" (made of high-stability piezoelectric ceramics, generally lead zirconium titanate)or a resistor and a capacitor to fix the frequency).
The entire circuit that generates the frequency is called an "oscillator", includes the resonant part (crystal, resonator, or RC), some capacitors, and a silicon chip and therefore is called a hybrid device. (An oscillator that uses a resistor and a capacitor to fix the frequency is called a "RC oscillator". An oscillator that uses a crystal to fix the frequency is called a "crystal oscillator".)
The oscillator includes, in addition to the frequency-fixing component just mentioned, an amplifier and capacitors.
Oscillators usually come in a metal can, but Epson also encapsulates them in plastic. Typically an oscillator can has 4 pins. Inside the can is all the components of the oscillator. One applies DC power on 2 of the pins, and the oscillating signal (the "CLK OUT") appears on another pin. (The remaining pin is unused).
An oscillator can also be made from scratch using crystal in a (2-pin) metal can, a couple of capacitors, an resitor and an inverter. In either case, the frequency is printed on the top of the crystal or oscillator.
Many microcontrollers have 2 pins (typically labeled "XTAL1" and "XTAL2", or "OSC1" and "OSC2", or something similar) that are designed to be directly connected to the 2 pins of a crystal. (Capacitors from those pins to VCC and GND are also part of the recommended circuit). An inverter inside the microcontroller acts as the amplifier, and the crystal and capacitors make up the rest of the oscillator.
In systems with multiple CPUs, it is often simpler, cheaper, and more reliable (avoiding metastability problems) to use a single crystal (rather than a dedicated crystal for each CPU). CPUs (and many other components) often have a single "CLK" pin designed to be connected to the wire used to send that "clock signal" (a fixed frequency) everywhere.
Unfortunately, many people confuse the "clock signal" generated by an oscillator (a simple metronome beat, tone, at constant frequency) with far more complicated "clock system"s that keep track of seconds, minutes, hours, and sometimes days, weeks, months, and years.
