Dual Synthesizer for Dual Conversion Radio Design

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robismyname

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I'm considering using a National Semiconductor Dual Synthesizer for a dual conversion radio design . The part number is LMX2525. But I am not certain if this fits my application. The first IF section is 374MHz, second IF is 70MHz. Assuming that a PLL is absolutely necessary does this dual synthesizer fit the application? If it does then I ask what should be the frequency of my oscillator?
 

Not knowing your RF freq...

RF + 374MHz = LO1

374MHz +70MHz = LO2

Maybe try that first. Do a spur analysis.
 

Why dual conversion? Seems like your frequency plan is perfectly suitable for single frequency conversion and this results in much less spurs
 

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