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I took the quiz too - here are the Q's but not the A's - RF Cafe Forums

Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views. It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if you would like to post something on RF Cafe's Facebook page, please do.

Below are all of the forum threads, including all the responses to the original posts.


 Post subject: I took the quiz too - here are the Q's but not the A's
Posted: Wed Jan 03, 2007 9:44 pm 
 
Captain
User avatar

Joined: Fri Jul 16, 2004 4:10 pm
Posts: 8
Location: Tennessee
Hey, I took the #$%@ quiz and it thinks I'm borderline - got an 85. Of course, I didn't see any warning that I should have a formula sheet and calculator onhand - it sure would have helped.

I didn't like that it doesn't even tell you which questions you get right or wrong. Just a score at the end. I'd like to know how anyone got the 147 scores? My guess is taking it multiple times under different names.

Anyway, I did screen captures on each question just so I could have a record to check myself. Here they are for your study period prior to taking the quiz.

Anyone care to give us all your choices for the answers - showing your solutions gets you extra credit. :-D

QUIZ #1


If a 10MHz modulated signal is transmitted on a 2GHz carrier frequency, what is the best fit for the minimum sample rate rate required to demodulate the signal?
A: 30MSa/s
B: 10MSa/s
C: 2GSa/s
D: 5GSa/a


This type of antenna is capable of being used at more than one frequency band due to the presence of a parallel LC network:
A: Dummy antenna
B: Loop antenna
C: Isotropic antenna
D: Trap antenna

What is 2 RADAR miles?
A: 10.7us
B: 12.4us
C: 21.3us
D. 24.7us


What would be the smallest and most efficient aperture for a slot antenna radiation of a 2GHz signal?
A: 6 inches
B: 12 inches
C: 0.5m
D: 3 inches

A 0.5m stub (monopole) antenna over an infinite ground plane will be resonant at what fundamental frequency?
A: 300 MHz
B: 150 MHz
C. 600 MHz
D: 75MHz


What is the condition that would BEST indicate a Receiver Selectivity problem?
A: Two transmitters of similar modulation received into the same antenna amplifier and filter section.
B: An increase in the noise floor impacting C/N ratio of the desired signal.
C: An out-of-channel signal that is able to force the receiver LNA into compression thus impacting sensitivity.
D: A high level signal in channel that prevents desired signals from being received.


What is the voltage gain from 1 uV to 0.1 V?
A: 140 dB
B: 70 dB
C: 100 dB
D: 50 dB


An antenna is assumed to be matched when
A: Impedance is approximately equal to 50 ohms.
B: SWR (standing wave ratio) equals approximately 0.
C: Impedance is equivalent to free space impedance.
D: Antenna impedance is purely resistive.

What is the average power of a pulsed signal with the following characteristics: (PRF = 1 kHz, PW = 1 us, Peak Power = 100 kW)?
A: 1 W
B: 10 W
C: 100 W
D: 1 kW


Is the PRF (Pulse Repetition Frequency) of a puls is 5 kHz, what is the PRI (Pulse Repetition Interval)?
A: 20 us
B: 200 us
C: 500 us
D: 2 ms

What type of jitter is UNBOUNDED?
A: Random Jitter
B: Periodic Jitter
C: Data Dependent Jitter
D: Duty cycle Jitter


Which is not a factor increasing spectral emissions?
A: Increased risetime
B: Increased attenuation
C: Memory effects
D: Baseband signal clipping

What reading represents the lowest level signal?
A: 87 dBuV
B: -10 dBm
C: 0.1V
D: -40 dBW


An input to a power sensor says DO NOT EXCEED 100 V. What is that power level?
A: 19 dBm
B: 53 dBm
C: 130 dBuV
D: 33 dBm

If a 20 MHz modulated signal is transmitted on a 1 GHz carrier, what is the bandwidth required to see the 5th order intermodulation products?
A: 100 MHz
B: 1.05 GHz
C: 5 GHz
D: 1010 MHz


Which is an expected advantage of MIMO (Multi-input Multi-output) technology?
A: Improved spectral efficiency
B: Improved spatial efficiency
C: Reduced receiver complexity
D: Lower latency

What component is not likely to have non-linear response?
A: Band pass LC filter
B: Mixer
C: Power Amp
D: Oscillating Filter


To reduce common mode coupling from antenna to receiver, one might:
A: Eliminate the balun
B: Change Rx antenna polarization
C: Use twisted pair or change the dielectric constant
D: Put a ferrite core on the antenna feed line

What is the approximate average power of the five power meter readings: (+40 dBm, +10 dBm, +3 dBm, +10 dBm, +2 dBm)?
A: ~13 dBm
B: ~33 dBm
C: ~10 dBm
D: None of the above


A baseband system has a residual EVM of 3%. If a gain block with a 4% EVM is added to the baseband and the errors are able to sum coherently, what would the overall system EVM approach?
A: 5%
B: 12%
C: 7%
D: 1%


 
   
 
 Post subject:
Posted: Thu Jan 04, 2007 8:12 pm 
 
Captain
User avatar

Joined: Tue Jan 06, 2004 1:51 pm
Posts: 19
Thanks dude. I started taking the quiz and then stopped after the I discovered that I'd need to do like you siad and grab a cheat sheet and a calculator. I'll work out the Q's that you got down. Don't know if they switch them around or not, but it can't hurt to get these down first. I'll check back after I've done it. Might also get the Quiz 2 questions as well.


 
   
 
 Post subject:
Posted: Tue Jan 23, 2007 3:56 pm 
 
Site Admin
User avatar

Joined: Mon Jun 27, 2005 2:02 pm
Posts: 392
Location: Germany
Thanks for taking the time and writing this quiz!

Soliving it is a matter of calculations and is very useful to brush up some basic knowledge and formulas.

Where I come from such questions are being asked in interviews too, where I am now if you will dare asking a candidate such questions your ass will be kicked! And I am not joking on the last one...

_________________
Best regards,

- IR


 
   
 
 Post subject:
Posted: Wed Jan 24, 2007 12:01 am 
 
Captain

Joined: Wed Apr 05, 2006 7:50 am
Posts: 7
IR wrote:
Where I come from such questions are being asked in interviews too, where I am now if you will dare asking a candidate such questions your ass will be kicked! And I am not joking on the last one...


Are you serious? I assume you are not located in the U.S. (not that the U.S. hasn't gotten PC enough to prevent it). How do you determine whether a candidate is qualified?

By the way, great job of the Circuits form, dude. Your effort keeps it alive.
:smt038 =D>


 
   
 
 Post subject:
Posted: Wed Jan 24, 2007 12:03 am 
 
Site Admin
User avatar

Joined: Mon Jun 27, 2005 2:02 pm
Posts: 392
Location: Germany
Many thanks!

You know the nature of the candidate just by going through his CV and ask him top level questions like if you have experience in this or that and also based on general impression about the person during the interview.

Very superficial I know, but this is how it is going here.

_________________
Best regards,

- IR




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