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Frequency error in ppm
Translate oscillator tolerance into actual frequency error.
HB3YAQ · Ajdin HadzicLearning to take awayhttps://hb3yaq.ch/en/tools/ppm
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Formula & context
Δf[Hz] = f[MHz] · ppm
One ppm is one part per million. The same relative error produces a larger absolute offset at higher frequencies. The sign denotes error, not a particular application’s correction setting.
A worked example
1 ppm is 145 Hz at 145 MHz and 435 Hz at 435 MHz.
Assumptions & limits
Not a calibration procedure. Real correction needs a known reference, warm-up time and allowance for temperature drift.
Frequency error and SDR calibrationUnderstand the reasoning →From reading to experimenting
Frequency error in ppm
1 ppm is 145 Hz at 145 MHz and 435 Hz at 435 MHz.
Open example with starting values →Frequency: 145 MHz · Relative error: 1 ppmBack to the learning article →Then change exactly one value. Compare the result and use the formula to explain why it changes. The model limits below the calculator also apply here.