the datasheet only gives us the noise figure of 'IF front end' of freqency higher than 50MHz,but how about the noise in low freqency?
The 'IF front end' you're referring to on the datasheet is actually the RF input. The minimum RF input on the AD8348 is 50 MHz. The minimum baseband output measured at the AD8348 output is 10 MHz. To measure baseband frequencies down to 100 Hz - 100KHz would be quite a challenge because there will be a few things that will interfere with the measurement at such low frequecies such as phase noise of the LO, 1/f noise, and the DC tone.
I would like to know if AD8348 is suitable for narrow-band ZIF appliciation. I measured the noise between 1KHz ~ 100KHz with spectrum analyzer,the noise reached -50dbm/Hz as AGC of AD8348 is maxed. when I disable AD8348 the noise is no more than -90dbm/Hz. Is the noise so high on this IC? thanks a lot!
I measured noise at IMXO/QMXO,as the VGIN=0v.
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