Crystals and receivers question
08-12-2007, 02:09 AM
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Crystals and receivers question
Hi what is the difference between single and dual conversion?
Can I use single conversion crystal in dual conversion ESC?
Can I use single conversion crystal in dual conversion ESC?
08-12-2007, 12:17 PM
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RE: Crystals and receivers question
Difference between SC and DC: SC have one mixing-stage (SuperHeteroDynamic), DC have two mixing-stages.
SC use a xtal which swings 455kHz lower than the TX-frequency. The bandpassfilter behind makes sure only the right ferquency is passed to dekoding.
DC use a xtal which swings 10,7MHz lower than the TX-frequency. In addition there is a second stage behind this which has a fixed xtal at 10,245MHz thus making (among other mix-products) a signal at 455kHz... same as the SC`s single stage. Having two Superhet-steps do supress some harmonic spyrious from frequencies above our band.
I have never heard anyone using swapable xtals in an ESC... [X(] An ESC is an Electronic Speed Control.
I assume you meant if you can use single conversion xtal in a dualconversion receiver...? The answer to this is short: NO.
(You can of course use the wrong xtal, but it will "receive" signals far from those we use for RC)
SC use a xtal which swings 455kHz lower than the TX-frequency. The bandpassfilter behind makes sure only the right ferquency is passed to dekoding.
DC use a xtal which swings 10,7MHz lower than the TX-frequency. In addition there is a second stage behind this which has a fixed xtal at 10,245MHz thus making (among other mix-products) a signal at 455kHz... same as the SC`s single stage. Having two Superhet-steps do supress some harmonic spyrious from frequencies above our band.
I have never heard anyone using swapable xtals in an ESC... [X(] An ESC is an Electronic Speed Control.
I assume you meant if you can use single conversion xtal in a dualconversion receiver...? The answer to this is short: NO.
(You can of course use the wrong xtal, but it will "receive" signals far from those we use for RC)
