Key Topic 46: Filters and IF Amplifiers

Question 1

3-46F1: What is the primary purpose of the final IF amplifier stage in a receiver?

A. Dynamic response.
B. Gain.
C. Noise figure performance.
D. Bypass undesired signals.

Answer 1

B. Gain

Question 2

3-46F2: What factors should be considered when selecting an intermediate frequency?

A. Cross-modulation distortion and interference.
B. Interference to other services.
C. Image rejection and selectivity.
D. Noise figure and distortion.

Answer 2

C. Image rejection and selectivity.

Question 3

3-46F3: What is the primary purpose of the first IF amplifier stage in a receiver?

A. Noise figure performance.
B. Tune out cross-modulation distortion
C. Dynamic response.
D. Selectivity.

Answer 3

D. Selectivity.

Question 4

3-46F4: What parameter must be selected when designing an audio filter using an op-amp?

A. Bandpass characteristics.
B. Desired current gain.
C. Temperature coefficient.
D. Output-offset overshoot.

Answer 4

A. Bandpass characteristics.

Question 5

3-46F5: What are the distinguishing features of a Chebyshev filter?

A. It has a maximally flat response over its passband.
B. It only requires inductors.
C. It allows ripple in the passband.
D. A filter whose product of the series- and shunt-element impedances is a constant for all frequencies.

Answer 5

C. It allows ripple in the passband.

Question 6

3-46F6: When would it be more desirable to use an m-derived filter over a constant-k filter?

A. When the response must be maximally flat at one frequency.
B. When the number of components must be minimized.
C. When high power levels must be filtered.
D. When you need more attenuation at a certain frequency that is too close to the cut-off frequency for a constant-k filter.

Answer 6

D. When you need more attenuation at a certain frequency that is too close to the cut-off frequency for a constant-k filter.