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== Crystals == <!-- "Colorburst crystal" redirects here. --> An NTSC or PAL television's color decoder contains a colorburst [[crystal oscillator]]. Because so many analog color TVs [[Digital television transition|were produced]] from the 1960s to the early 2000s, [[economies of scale]] drove down the cost of colorburst crystals, so they were often used in various other applications, such as [[Electronic oscillator|oscillators]] for [[microprocessor]]s or for [[amateur radio]]: 3.5795 MHz has since become a common [[QRP operation|QRP]] calling frequency in the [[80-meter band]], and its [[frequency multiplier|doubled]] frequency of 7.159 MHz is a common calling frequency in the [[40-meter band]]. Tripling this frequency is also how [[FM broadcasting|FM radio]] circuits came to use a nominally 10.7 MHz [[intermediate frequency]] in [[Superheterodyne transmitter|superheterodyne]] conversion. {{Table alignment}} {| class="wikitable sortable col3center" |+ Non-television uses of NTSC color burst frequency<br/> (generally only in the NTSC version of each device):<br/> ''f'' = 315 MHz/88 = 3.579{{Overline|54}}{{Efn|name=repeating decimal}} MHz ! Component || Frequency || Ratio |- | [[Intellivision]] CPU ||rowspan=2| 0.8949 MHz ||rowspan=2| {{Sfrac|4}}''f'' |- | [[TRS-80 Color Computer]] CPU (normal speed) |- | [[Apple II]] CPU (short cycles only, one in 65 cycles is longer)||rowspan=4| 1.0227 MHz ||rowspan=4| {{Sfrac|2|7}}''f'' |- | [[VIC-20]] CPU |- | [[Commodore 64]] CPU |- | [[Commodore 128]] CPU (SLOW & [[Commodore 64|C64]] compatible modes) |- | [[Atari 2600]] CPU<ref name="atari2600"> Atari 2600 Specifications http://problemkaputt.de/2k6specs.htm</ref> ||rowspan=2| 1.1932 MHz ||rowspan=2| {{Sfrac|3}}''f'' |- | [[Intel 8253]] interval timer in IBM PC (remains in use {{As of|2008|alt=today}}) |- | [[Fairchild Channel F|Fairchild Video Entertainment System]] CPU ||rowspan=6| 1.7898 MHz ||rowspan=6| {{Sfrac|2}}''f'' |- | [[Magnavox Odyssey 2|Odyssey 2]] CPU |- | [[Atari 8-bit computers]]<ref name="altirraHRM">{{cite book |title=Altirra Hardware Reference Manual |chapter=3.3 Cycle Timings |page=43 |first=Avery |last=Lee |date=2024-09-21 |access-date=2024-11-27 |url=http://www.virtualdub.org/downloads/Altirra%20Hardware%20Reference%20Manual.pdf#page=43}}</ref> and [[Atari 7800]] CPU |- | [[Commodore Plus/4]] CPU |- | [[Nintendo Entertainment System]] CPU |- | TRS-80 Color Computer 3 CPU (fast mode) |- | [[Commodore 128]] CPU (FAST & CP/M modes) || 2.0454 MHz || {{Sfrac|4|7}}''f'' |- |rowspan=2| [[Super Nintendo Entertainment System]] CPU || 2.6847 MHz || {{Sfrac|3|4}}''f'' |- <!--For some reason, adding "rowspan=7" to the following doesn't work.--> | 3.5795 MHz ||style=text-align:center| ''f'' |- | [[Master System]] CPU ||rowspan=6| 3.5795 MHz ||rowspan=6| ''f'' |- | [[MSX]] CPU |- | [[Amateur radio]] Tx/Rx crystal for 80m band |- | [[ColecoVision]] CPU |- | [[Yamaha_OPL|Yamaha OPL and OPL2]] FM synthesis sound chips |- | [[Advanced Configuration and Power Interface|ACPI]] power management timer |- | CPU of [[IBM Personal Computer]] 5150 || 4.7727 MHz || {{Sfrac|4|3}}''f'' |- | Commodore [[Amiga]] CPU || rowspan="5" | 7.1591 MHz || rowspan="5" | 2''f'' |- | CPU of [[Tandy 1000#Tandy 1000 TX and Tandy 1000 SX|Tandy 1000 SX]]<ref>In normal (high speed) mode. The 1000 SX also has a slower 4.77 MHz mode ({{Frac|4|3}}''f'' ) for IBM PCjr compatibility.</ref> (and many other IBM PC-XT clones) |- | NEC [[TurboGrafx-16]] CPU |- | [[Yamaha TX81Z]] synthesizer CPU |- | [[Amateur radio]] Tx/Rx crystal for 40m band |- | [[Sega Genesis]] CPU || 7.6705 MHz || {{Sfrac|15|7}}''f'' <!-- The Genesis has a 53.693 MHz (15 times f) crystal oscillator, as can be seen here: https://d3nevzfk7ii3be.cloudfront.net/igi/U5BMTgUf53DjnSxe --> |- |Intermediate frequency of FM radio superheterodyne circuits |10.7386 MHz |3''f'' |- | [[High Precision Event Timer]] (typical) || 14.3181 MHz || 4''f'' |} {{Table alignment}} {| class="wikitable sortable col3center" |+ Non-television uses of PAL colour burst frequency<br/> (generally only in the PAL version of each device):<br/> ''f'' = 283.75 Γ 15625 Hz + 25 Hz = {{val|4.43361875|u=MHz}} ! Component || Frequency || Ratio |- | [[Commodore 64]] CPU ||rowspan=2| 0.9852 MHz ||rowspan=2| {{Sfrac|2|9}}''f'' |- | [[Commodore 128]] CPU (SLOW & [[Commodore 64|C64]] compatible modes) |- | [[Atari 2600]] CPU || 1.182298 MHz<ref name="atari2600"/> || {{Sfrac|4|15}}''f'' |- | [[VIC-20]] CPU || 1.1084 MHz || {{Sfrac|1|4}}''f'' |- | [[Nintendo Entertainment System]] CPU<ref name="nesdev">[http://wiki.nesdev.com/w/index.php/Clock_rate NES DEV wiki: Clock Rate]</ref> || 1.662607 MHz || {{Sfrac|3|8}}''f'' |- | [[Atari 8-bit computers]] CPU<ref name="altirraHRM"/> ||rowspan=2| 1.7734475 MHz ||rowspan=2| {{Sfrac|2|5}}''f'' |- | [[Dendy (console)]] NES clone CPU<ref name=nesdev/> |- | [[Commodore 128]] CPU (FAST & CP/M modes) || 1.9704 MHz || {{Sfrac|4|9}}''f'' |- |rowspan=2| [[Super Nintendo Entertainment System]] CPU || 2.6601712 MHz || {{Sfrac|3|5}}''f'' |- | 3.546895 MHz ||style=text-align:center| {{Sfrac|4|5}}''f'' |- | Commodore [[Amiga]] CPU || 7.09379 MHz || {{Sfrac|8|5}}''f'' |}
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