RF Cascade Workbook

Copyright

1996 -
2016

Webmaster:

Kirt
Blattenberger,

BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...

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RF Cafe Quiz #1

All RF Cafe quizzes would make perfect fodder for employment interviews for technicians or engineers - particularly those who are fresh out of school or are relatively new to the work world. Come to think of it, they would make equally excellent study material for the same persons who are going to be interviewed for a job.

**Click here for the complete list of *** RF Cafe
Quizzes*.

Note: Many answers contain passages quoted in whole or in part from the text.

1. What is the impedance of free space?

a) 50 Ω

b) 120π Ω

c) 75 Ω

2. What happens to the noise figure of a receiver when a 10 dB attenuator is added at the input?

a) Noise figure increases by 10 dB

b) Noise figure decreases by 10 dB

c) Noise figure doesn't change

3. An RF system has a linear throughput gain of +10 dB and an output 3rd-order intercept point (OIP3) of +30 dBm. What is the input 3rd-order intercept point (IIP3)?

a) +20 dBm

b) +40 dBm

c) +30 dBm

4. Which filter type has the greatest selectivity for a given order (i.e., N=5)?

a) Bessel

b) Chebyshev (ripple=0.1 dB)

c) Butterworth

5. Which mixer spurious product is a 5th-order product?

a) 1*LO + 5*RF

b) 6*LO - 1*RF

c) 3*LO - 2*IF

6. A 2.8 GHz oscillator is phase-locked to a 10 MHz reference oscillator that has a single-sided phase noise of -100 dBc at 1 kHz offset. What is the single-sided phase noise of the 2.8 GHz oscillator at 1 kHz offset?

a) -48.6 dBc

b) -100 dBc

c) -51.1 dBc

7. What is the power of a 2 V

a) -20.0 dBm

b) +10.0 dBm

c) +19.0 dBm

8. Which 2-port S-parameter is commonly referred to as "reverse isolation" in an amplifier?

a) S21

b) S22

c) S12

9. What are the minimum and maximum combined VSWR limits at an interface characterized by a 1.25:1 VSWR and a 2.00:1 VSWR?

a) 1.75:1 (min), 2.25:1 (max)

b) 1.60:1 (min), 2.50:1 (max)

c) 0.75:1 (min), 3.25:1 (max)

10. An ideal directional coupler has a directivity of 25 dB and an isolation of 40 dB. What is its coupling value?

a) 65 dB

b) 40 dB

c) 15 dB

Need some help? Click here for the answers and explanations.