EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: rvmeush on July 27, 2013, 12:57:07 am
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I have an old RCA WR-50 rf sweep generator that can accept an external quartz crystal to generate a marker signal in the sweep output. Quartz crystals seem to be somewhat scarce and very pricey these days, and I was wondering if a ceramic resonator of the same frequency could be substituted in place of the crystal? Aside from the different mounts for the two devices, would there be any other issues? Thanks.
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Quartz crystals seem to be somewhat scarce and very pricey these days
Really? Where are you looking? My observation has been the opposite: resonators are harder to find, but crystals are common and have become nearly as cheap (or cheaper, surplus.)
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Yeah, I've completely given up on keeping resonators stocked because it's just not worth the effort to find good, cheap ones just to save a cent or two. Mouser is flooded with crystals, just plug in the frequency you want and you'll find as many crystals at that frequency as you thought there would be total.....
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Crystals have much better accuracy.
It sounds like you aren't looking properly.
http://www.mouser.com/Passive-Components/Frequency-Control-Timing-Devices/Crystals/_/N-6zu9fZscv7?FS=True&Ns=Pricing (http://www.mouser.com/Passive-Components/Frequency-Control-Timing-Devices/Crystals/_/N-6zu9fZscv7?FS=True&Ns=Pricing)|0
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They can for non-critical applications.
Crystals tend to be more accurate and stable than resonators.
A crystal oscillator normally has a couple of low value (pf) capacitors. Changing their value might alter the crystal's frequency by a couple of kilohertz (out of several megahertz).
Whereas a 100pF swing in the capacitor values around a ceramic resonator oscillator might change frequency by 100kHz or more (out of several megahertz).
This wide swing is useful for some radio transmitter and receiver circuits. However in other cases the accuracy and repeatability of a quartz crystal oscillator may be preferred.
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I should have been more specific - one particular frequency I'm looking for is 455Khz. The Mouser link doesn't list that one.
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Look for muRata
CSB 455
Ceramic resonator loading capacity for integrated.
• Frequency: 455 KHz
• Frequency Tolerance: ± 0,5 %
• Frequencystabilität: ± 0,3 %
• Anschluß: 2-pin.
Manufacturer : MURATA
Factory number : CSB455E
Package weight : 0.0004 kg
RoHS : conform
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Crystals have much better accuracy.
But resonators are accurate enough for a large proportion of applications applications, and often come with built-in capacitors.
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455kHz resonators are also available ( along with 10.7MHz ones) as binned selections with a defined narrow pass band as IF filters. These have a closer tolerance selection during manufacture, and cost a little more for the binning. and are identified by coloured dots on the front as to which bin they are in.