Editing Electronic oscillator (section)

===Tunability===
The frequency of RC and LC oscillators can be tuned over a wide range by using variable components in the filter.  A [[microwave cavity]] can be tuned mechanically by moving one of the walls. In contrast, a [[crystal oscillator|quartz crystal]] is a mechanical [[resonator]] whose [[resonant frequency]] is mainly determined by its dimensions, so a crystal oscillator's frequency is only adjustable over a very narrow range, a tiny fraction of one percent.{{sfn|Gottlieb|1997|p=39-40}}<ref name="Froehlich">{{cite book
 | last1  = Froehlich
 | first1 = Fritz E.
 | last2  =  Kent
 | first2 = Allen
 | title  = The Froehlich/Kent Encyclopedia of Telecommunications, Volume 3
 | publisher = CRC Press
 | date   = 1991
 | location = 
 | pages  = 448
 | language = 
 | url    = https://books.google.com/books?id=QQcfD_iWlPYC&dq=%22crystal+oscillator%22+tuning+stiffness&pg=PA448
 | doi    = 
 | id     = 
 | isbn   = 0824729021
 }}</ref><ref name="Misra">{{cite book
 | last1  = Misra
 | first1 = Devendra 
 | title  = Radio-Frequency and Microwave Communication Circuits: Analysis and Design
 | publisher = John Wiley
 | date   = 2004
 | location = 
 | pages  = 494
 | language = 
 | url    = https://books.google.com/books?id=7nWN_pGQKnMC&dq=%22crystal+oscillator%22+pulling+%22tuning+range%22&pg=PA494
 | doi    = 
 | id     = 
 | isbn   = 0471478733
 }}</ref><ref name="Terman">{{cite book
 | last1  = Terman
 | first1 = Frederick E.
 | title  = Radio Engineer's Handbook
 | publisher = McGraw-Hill
 | date   = 1943
 | location = 
 | pages  = 497
 | language = 
 | url    = http://www.itermoionici.it/letteratura_files/Radio-Engineers-Handbook.pdf
 | doi    = 
 | id     = 
 | isbn   =
 }}</ref><ref name="FrequencyManagement">{{cite web
  | title = Oscillator Application Notes
  | work = Support
  | publisher = Frequency Management International, CA
  | date = 
  | url = http://www.frequencymanagement.com/web_pdfs/cat_pdfs_applicationNotes/45-49.PDF
  | format = 
  | doi = 
  | access-date = October 1, 2015}}</ref>
<ref name="Scroggie">{{cite book
 | last1  = Scroggie
 | first1 = M. G.
 | last2  = Amos
 | first2 = S. W.
 | title  = Foundations of Wireless and Electronics
 | publisher = Elsevier
 | date   = 2013
 | location = 
 | pages  = 241–242
 | language = 
 | url    = https://books.google.com/books?id=ihABBQAAQBAJ&dq=%22fixed+frequency%22+%22hardly+anything+about+it+that+can+vary%22&pg=PA242
 | doi    = 
 | id     = 
 | isbn   = 978-1483105574
 }}</ref>
<ref name="Vig">Vig, John R. and Ballato, Arthur "Frequency Control Devices" in {{cite book
 | last1  = Thurston
 | first1 = R. N. 
 | last2  = Pierce
 | first2 = Allan D.
 | last3  = Papadakis
 | first3 = Emmanuel P.
 | title  = Reference for Modern Instrumentation, Techniques, and Technology: Ultrasonic Instruments and Devices II
 | publisher = Elsevier 
 | date   = 1998
 | location = 
 | pages  = 227
 | language = 
 | url    = https://books.google.com/books?id=0lvCkB6y4dwC&dq=%22crystal+oscillator%22+tuning+stiffness&pg=PA227
 | doi    = 
 | id     = 
 | isbn   = 0080538916
 }}</ref>   Its frequency can be changed slightly by using a [[trimmer capacitor]] in series or parallel with the crystal.{{sfn|Gottlieb|1997|p=39-40}}