Which of the following receiver circuits can be effective in eliminating interference from strong out-of-band signals?
Why Strong signals outside the band you are listening to cause trouble by overloading the RF amplifier and mixer, generating intermodulation products and blocking before any later filtering can help. A front-end filter or preselector sits ahead of those stages and attenuates the offending energy while passing the band of interest, so the first active devices never see it. The rule of thumb is that overload must be cured at the earliest point in the signal chain.
Watch out A narrow IF filter comes after the mixer, so it sharpens selectivity between signals in the passband but cannot undo distortion already created by an out-of-band signal overloading the front end. A notch filter removes a single interfering carrier inside the passband, and a product detector only demodulates SSB and CW.
Out-of-band trouble needs an out-front fix: preselector before the mixer, not IF filtering after it.