RF Quiz #1
1. What is the impedance of free space?
377ou
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) Chebychev (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 Vpk-pk sine wave across a 50 ohm load?
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)