Which of the following receiver circuits can be effective in eliminating interference from strong out-of-band signals?
A front-end filter or preselector✓الإجابة الصحيحة
A narrow IF filter
A notch filter
A properly adjusted product detector
الشرح
Out-of-band signals have to be removed before they reach the first nonlinear stage, and a front-end filter or preselector does this ahead of the mixer. A narrow IF filter or a notch filter acts only after conversion, by which time the spurious responses have already been generated.