Quote:
Originally Posted by Radio Wrangler
I'm afraid that can't happen.
Say there are two stations one on frequency A, one on frequency B, and the 3rd order intermod products they create will be on ABS(2*A-B) and ABS(2*B-A).
Let's say the tuner is trying to listen to a station on one of these frequencies. Because the wanted signal and the unwanted intermod are both on the same frequency, they both get converted to the IF frequency of the tuner, and appear there both on the same frequency, both in the passband. You hear interference.
No amount of filtering in the IF will separate two signals if they're both on the same frequency.
Once that intermod product has formed, it is too late. It is on the tuned frequency and uit will go straight down the receiver through all its filters, just like a real signal on that frequency.
Unfortunate, but we're stuck with this. The only solution is to get the RF and mixer good and linear.
David
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I see, the third order intermodulation products can be too close to the fundamental signals to be filtered out within the passband. What a pain!