ECET310 Week 2 TEST | Complete Solution

ECET310   Week 2 TEST     NAME:______________________________.     GRADE=            /32

Note: 
There are 2 pages. 
3 points for each blank.
Complete the test and put into drop box (week 2 TEST) for grade.  Keep answers in 2 digits after decimal point.   Must submit in time (time stamp verified).   No grade for no or wrong units.
1.
     Ap1=10dB        Ap2=20dB        Ap3=30dB
     NF1=3dB        NF2=4dB        NF3=5dB

A three stage amplifier is shown. The operating bandwidth is 300 KHz at a temperature of 20° C.  The output load is 1.5KΩ.
a.Total power gain as a number = ____________
b.total NF as a number = ____________
c.Total thermal noise power at input = __________
d.Total noise power at  output  = ____________
e.Output noise voltage = ____________



2. Determine percent of total harmonic distortion if fundamental has RMS voltage of 5 V, 2nd     harmonic is 1V, and 4th harmonic is 0.7V and 5th harmonic is 0.5V.
        Answer= ______________


3. Note:  R=1Ω,  C=79.58uF,  L=477.46uH
For the circuity above, the frequency of source signal is tunable, and we intend to tune to resonant frequency Fr.  (The followings are sequential events)
a)    Fr= _____________
b)    When the circuit is tuned to Fr, the current through R measured using DMM  = _____________; and Power delivered to that 1Ω  resistor = ___________.
 (note:  1V in the circuit is the peak value)
c)    The system requires that the engineer to increase the resonant frequency to be 10 times of Fr found in (a) and can only change capacitor and keep R and L unchanged. 
The new capacitor value = _____________.
d)    The engineer replaces the R in the circuit above with a 100Ω resistor, then resonant frequency of this new circuit, Fr=_____________.
e)    After operating at Fr for a while, suddenly capacitor in the circuit is burnt to become OPEN,  then we shall see that the current through R (100Ω ) measured using DMM become ___________ (increased, decreased, or unchanged).