Difference between revisions of "Oscillator"

From OpenCircuits
Jump to navigation Jump to search
(mention the "negative resistance test")
 
(63 intermediate revisions by 44 users not shown)
Line 1: Line 1:
−
[http://quoits.cn/zila-bakarin.html zila bakarin] [http://bobmarlyuprising.clung.cn/index.html bob marly uprising] [http://blackgirl.midways.cn/index.html black girl] [http://wonted.cn/www-cisl-scuola/index.html www cisl scuola it] [http://ballandoalbuoi.romanikki.cn/index.html ballando al buoi] [http://benybanacci.kittiss.cn/index.html beny banacci] [http://bouthwaternodoubt.midways.cn/index.html bouth water no doubt] [http://basameelcueo.clung.cn/index.html basame el cueo] [http://knock-knock.cn/www-oneone/index.html www oneone] [http://buonissimo.kittiss.cn/index.html buonissimo] [http://bandierarealeinglese.kittiss.cn/index.html bandiera reale inglese] [http://snailtail.cn/ya-rayeh/index.html ya rayeh] [http://knock-knock.cn/www-sabb-com/index.html www sabb com] [http://bellevillerendezvous.romanikki.cn/index.html belleville rendez vous] [http://knock-knock.cn/wwo-vieni/index.html wwo vieni pele] [http://wonted.cn/www-la-buona/index.html www la buona stella it] [http://battaglierovalzer.clung.cn/index.html battagliero valzer] [http://kitmun.cn/yodeyma.html yodeyma] [http://bonhommeenmousse.midways.cn/index.html bonhomme en mousse] [http://quoits.cn/zion-ylenox.html zion ylenox] [http://quoits.cn/zanela-me-svjetla.html zanela me svjetla] [http://bessette.clung.cn/index.html bessette] [http://bennasifeat.kittiss.cn/index.html bennasi feat] [http://wonted.cn/www-uniud/index.html www uniud it] [http://knock-knock.cn/www-medici/index.html www medici del lavoro it] [http://snailtail.cn/www-sine-com/index.html www sine com] [http://kitmun.cn/zucchero-dune.html zucchero dune mosse] [http://wonted.cn/wish-i-could/index.html wish i could fly  billy mayer] [http://snailtail.cn/www-testi/index.html www testi canzoni it] [http://kitmun.cn/zinedine.html zinedine] [http://kitmun.cn/zion-y.html zion y lenox te hago el amor] [http://knock-knock.cn/www-maneie/index.html www maneie ro] [http://bolognaprive.kittiss.cn/index.html bologna prive] [http://wonted.cn/www-musica-piva/index.html www musica piva it] [http://quoits.cn/annie.html annie] [http://knock-knock.cn/www-murphi/index.html www murphi it] [http://bitteresanam.kittiss.cn/index.html bit tere sanam] [http://kitmun.cn/youm-wara-youm.html youm wara youm] [http://kitmun.cn/ytunnel.html ytunnel probuild 344] [http://knock-knock.cn/ww-indire-it/index.html ww indire it] [http://snailtail.cn/yami-bakura/index.html yami bakura] [http://barbijakoroszpunka.romanikki.cn/index.html barbi jako roszpunka] [http://quoits.cn/zlokic.html zlokic] [http://bouniocattivi.fast-road.cn/index.html bouni o cattivi] [http://bali3d.fast-road.cn/index.html bali 3d] [http://bubbaraydudley.clung.cn/index.html bubba ray dudley] [http://quoits.cn/zaa-zaa.html zaa zaa] [http://quoits.cn/avalance-alley..html avalance alley. terrore sulla neve] [http://bebekzeljko.clung.cn/index.html bebek zeljko] [http://kitmun.cn/zdenka-podkapova.html zdenka podkapova] [http://bicicletasvital.clung.cn/index.html bicicletas vital] [http://quoits.cn/all-american.html all-american boys] [http://quoits.cn/zone-alarm-pro.html zone alarm pro] [http://knock-knock.cn/www-arabic-sex/index.html www arabic sex com] [http://brendarobles.clung.cn/index.html brenda robles] [http://wonted.cn/www-mewmewamichevincenti/index.html www mewmewamichevincenti it] [http://buscarperreo.midways.cn/index.html buscar perreo] [http://blueeiffel65.clung.cn/index.html blue eiffel65] [http://snailtail.cn/www-hotel-carlton/index.html www hotel carlton it] [http://snailtail.cn/www-gabrielealbertini/index.html www gabrielealbertini it] [http://quoits.cn/zelig-battute.html zelig battute] [http://wonted.cn/www-delfini/index.html www delfini it] [http://knock-knock.cn/www-regionecalabria/index.html www regionecalabria it] [http://quoits.cn/zivot.html zivot] [http://wonted.cn/www-campingbaiaverde/index.html www campingbaiaverde com] [http://kitmun.cn/zeus.html zeus] [http://bajaga.romanikki.cn/index.html bajaga] [http://buckley.midways.cn/index.html buckley] [http://quoits.cn/anna,-quel.html anna, quel particolare piacere] [http://bookmark.midways.cn/index.html book mark] [http://kitmun.cn/ypoferw.html ypoferw] [http://bornslippyunderworld.clung.cn/index.html born slippy underworld] [http://kitmun.cn/yerri-ribera.html yerri ribera] [http://knock-knock.cn/www-artec-it/index.html www artec it] [http://kitmun.cn/yashal-elisa.html yashal elisa] [http://bassistinti.fast-road.cn/index.html bassistinti] [http://kitmun.cn/yamana-ven-a.html yamana ven a bailar] [http://wonted.cn/www-teddy-it/index.html www teddy it] [http://knock-knock.cn/www-carsismo/index.html www carsismo] [http://billycrowford.romanikki.cn/index.html billy crowford] [http://bessanese.kittiss.cn/index.html bessanese] [http://bigtitsmovie.clung.cn/index.html big tits movie] [http://kitmun.cn/you-should-really.html you should really know] [http://knock-knock.cn/www-termediroma/index.html www termediroma com] [http://kitmun.cn/zigo-zago.html zigo zago] [http://quoits.cn/zoo-di-105.html zoo di 105] [http://snailtail.cn/yu-gi-oh-roms/index.html yu gi oh roms ps2] [http://bonnytyleretkarenanton.fast-road.cn/index.html bonny tyler et karen anton] [http://snailtail.cn/www-tracfone/index.html www tracfone com] [http://bsodiariodebridgetjones.clung.cn/index.html bso diario de bridget jones] [http://snailtail.cn/xbox-spinx-e/index.html xbox spinx e la mummia pasticciona] [http://bellissimo.fast-road.cn/index.html bellissimo] [http://kitmun.cn/za-za-za-climax.html za za za climax] [http://snailtail.cn/www-socialdistortion/index.html www socialdistortion com] [http://brasilcom.fast-road.cn/index.html brasil com] [http://wonted.cn/where-you-are/index.html where you are] [http://quoits.cn/zora.html zora] [http://barbielatina.clung.cn/index.html barbie latina] [http://bailazucchero.midways.cn/index.html baila zucchero] [http://billevens.romanikki.cn/index.html bill evens] [http://biografiabuerovallejo.kittiss.cn/index.html biografia buero vallejo] [http://bangbeng.romanikki.cn/index.html bang beng] [http://bluetooh.romanikki.cn/index.html bluetooh] [http://snailtail.cn/www-ilro-it/index.html www ilro it] [http://snailtail.cn/www-sunvalleyhotel/index.html www sunvalleyhotel it] [http://bud.midways.cn/index.html bud] [http://bwv1041.kittiss.cn/index.html bwv 1041] [http://beheaddingvideo.romanikki.cn/index.html beheadding video] [http://kitmun.cn/yarabe-de-palo.html yarabe de palo] [http://babybashsugarsugar.romanikki.cn/index.html baby bash sugar sugar] [http://snailtail.cn/yellows-kapras/index.html yellows kapras] [http://bellacocca.romanikki.cn/index.html bella cocca] [http://bellavacca.romanikki.cn/index.html bella vacca] [http://kitmun.cn/yatana-naked.html yatana naked] [http://quoits.cn/arrow-beach:.html arrow beach: la spiaggia della paura] [http://wonted.cn/www-gaia/index.html www gaia com] [http://benassibrother.clung.cn/index.html benassi brother] [http://berlinostradario.romanikki.cn/index.html berlino stradario] [http://quoits.cn/agente-porter.html agente porter al servizio di sua maestà] [http://snailtail.cn/xelenio/index.html xelenio] [http://boldandthebeautiful.kittiss.cn/index.html bold and the beautiful] [http://belgacomnet.midways.cn/index.html belgacom net] [http://quoits.cn/angeli-senza.html angeli senza cielo] [http://kitmun.cn/zarick-leon.html zarick leon] [http://quoits.cn/alta-bella-e.html alta bella e pericolosa] [http://knock-knock.cn/www-trannytrickvideos/index.html www trannytrickvideos com] [http://breakinoutleki.kittiss.cn/index.html breakin out leki] [http://kitmun.cn/yo-mataria.html yo mataria] [http://battiatotestodellecanzonelacura.clung.cn/index.html battiato testo delle canzone la cura] [http://bruno.midways.cn/index.html bruno] [http://snailtail.cn/x-box-zone/index.html x box zone] [http://budspenecer.clung.cn/index.html bud spenecer] [http://boccheemicrofonivideobocchinare.clung.cn/index.html bocche e microfoni video bocchinare] [http://kitmun.cn/yllka-gashi.html yllka gashi] [http://quoits.cn/zuritel-it.html zuritel it] [http://beavisbuttheaditaliano.clung.cn/index.html beavis butthead italiano] [http://knock-knock.cn/www-parco/index.html www parco giardino d italia it] [http://wonted.cn/www-tenbit/index.html www tenbit pl] [http://behaeded.clung.cn/index.html behaeded] [http://kitmun.cn/yu-gi-oh-da-colorare.html yu gi oh da colorare] [http://bobmalone.fast-road.cn/index.html bob malone] [http://snailtail.cn/xjapan/index.html xjapan] [http://kitmun.cn/yhe-servant.html yhe servant] [http://snailtail.cn/xxxsexy-girls/index.html xxxsexy girls] [http://snailtail.cn/www-pliva/index.html www pliva] [http://knock-knock.cn/webmail-uni2/index.html webmail uni2 dk] [http://boombastik.midways.cn/index.html boombastik] [http://biopsiamani.midways.cn/index.html biopsia mani] [http://quoits.cn/zona-erotica.html zona erotica] [http://knock-knock.cn/www-ciunga/index.html www ciunga it] The vast majority of electronic systems operate at some fixed frequency.
+
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.
 
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).
+
(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.
+
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 is therefore 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 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".)
 
An oscillator that uses a crystal to fix the frequency is called a "crystal oscillator".)
Line 12: Line 11:
 
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).
 
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.
+
An oscillator can also be made from scratch using crystal in a (2-pin) metal can, a couple of capacitors, a resistor and an inverter.
 
In either case, the frequency is printed on the top of the crystal or oscillator.
 
In either case, the frequency is printed on the top of the crystal or oscillator.
  
Line 18: Line 17:
 
that are designed to be directly connected to the 2 pins of a crystal.
 
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).
 
(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.
+
An inverter inside the microcontroller acts as the amplifier, and the crystal and capacitors make up the rest of the oscillator. Microcontrollers when connected directly to a crystal need to have capacitors attached that need to be percisely matched with other circuit components on the board.  Resonators tend to have the capacitor buildin reducing the amount of trial and error of capacitor selection.
  
 
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).
 
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).
Line 25: Line 24:
 
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.
 
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.
  
−
== for further reading ==
+
The "negative resistance test" measures the oscillation allowance of a crystal oscillator circuit.
 +
Most manufacturers recommend that the oscillation allowance of the circuit be at least five times the maximum resistance value of the quartz crystal unit used in the circuit.<ref>
 +
[http://www.ti.com/lit/an/slaa322b/slaa322b.pdf "MSP430 32-kHz Crystal Oscillators"].
 +
p. 5.
 +
</ref><ref>
 +
[http://www.foxonline.com/pdfs/osctheoryoper.pdf "Oscillator Theory of Operation"].
 +
p. 109.
 +
</ref><ref>
 +
[http://www.sii.co.jp/en/quartz/circuit-design/ "Oscillation Circuit Design Overview"].
 +
</ref><ref>
 +
[http://www.atmel.com/images/doc8333.pdf "AVR4100: Selecting and testing 32kHz crystal oscillators for Atmel AVR microcontrollers"].
 +
p. 12.
 +
</ref><ref>
 +
[http://www.ecsxtal.com/store/pdf/Oscillation-Circut-Design-Considerations.pdf "Oscillator Circuit Design Considerations"].
 +
p. 8
 +
</ref>
 +
 
 +
 
 +
 
 +
== Further reading ==
  
 
* [http://techref.massmind.org/techref/clocks.htm massmind: clocks]
 
* [http://techref.massmind.org/techref/clocks.htm massmind: clocks]
 
* [http://en.wikipedia.org/wiki/Crystal_oscillator Wikipedia: crystal oscillator]
 
* [http://en.wikipedia.org/wiki/Crystal_oscillator Wikipedia: crystal oscillator]
−
* [http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE
+
* [http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en021190 "App Note AN949: Making Your Oscillator Work" by Brett Duane]
 +
* [http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en020706 "App Note AN943: Practical PICmicro® Oscillator Analysis and Design" by Ruan Lourens]
 +
* [http://www.icmfg.com/technicaldata.html#crystal_data Crystal data]
 +
[[Category:Components]]

Latest revision as of 08:32, 8 January 2016

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 is therefore 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, a resistor 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. Microcontrollers when connected directly to a crystal need to have capacitors attached that need to be percisely matched with other circuit components on the board. Resonators tend to have the capacitor buildin reducing the amount of trial and error of capacitor selection.

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.

The "negative resistance test" measures the oscillation allowance of a crystal oscillator circuit. Most manufacturers recommend that the oscillation allowance of the circuit be at least five times the maximum resistance value of the quartz crystal unit used in the circuit.<ref> "MSP430 32-kHz Crystal Oscillators". p. 5. </ref><ref> "Oscillator Theory of Operation". p. 109. </ref><ref> "Oscillation Circuit Design Overview". </ref><ref> "AVR4100: Selecting and testing 32kHz crystal oscillators for Atmel AVR microcontrollers". p. 12. </ref><ref> "Oscillator Circuit Design Considerations". p. 8 </ref>


Further reading[edit]

Retrieved from "http://www.opencircuits.com/index.php?title=Oscillator&oldid=78094"