ECE 323 Design Project Due ___________
Note: This design project is equivalent to a take-home exam. You are to do your
own work and you may not consult with others. If you need help you may consult
your instructor.
You are to design an amplifier to boost the signal on a cable TV line. You should only
amplify the broadcast equivalent VHF channels 2-13 as well as the sub-band CATV
channels (see http://www.csgnetwork.com/tvfreqtable.html). The TV cable has a
characteristic impedance of 75 Ω. To avoid reflections, the input and output impedance
of you amplifier should be 75 Ω in the passband.
a) Midband gain of 10 ± 10%
b) Input resistance equal to 75 Ω ± 5%
c) Output resistance equal to 75 Ω ± 5%
d) Bandpass frequency response from 4 MHz to 219 MHz. Frequencies indicated
are –3dB cutoff points.
e) Use only capacitors, 1% resistors (see appendix H), and 2N3904 or 2N3906
transistors (see attached data sheets).
f) Output voltage swing must be at least 2 V p-p.
g) Use a single 10 V power supply.
h) AC couple the input and output.
i) Above specifications must be met for the full range of β indicated on the
transistor data sheets.
j) -3dB cutoff points of the frequency response should not depend on Cπ or Cµ.
Submit a report, which includes:
a) Schematic diagram of your design
b) Analysis clearly demonstrating that your design meets the above requirements for
the full range of β.
c) SPICE simulation results showing mid-band gain and –3dB cutoff frequencies.
d) SPICE simulation results showing output swing of at least 2 V p-p.
Note: You will be graded not only on correct design but also on the clarity with which
you present it. I should be able to easily follow your analysis. Resist the temptation to
“design by SPICE”, i.e. blindly adjusting your circuit until SPICE gives you the desired
results. SPICE simulation is for verification only. A design that meets spec. in SPICE
but has no supporting analysis will get no credit! However, if SPICE gives you results
much different from your analysis it usually indicates that either your analysis is wrong
or that your SPICE netlist/diagram is mis-wired.
For designs that meet the specifications, extra credit will be given for clever design to
reduce component count.
