ELEC 432
In the Lab
Part 1: Analysis
Before beginning your design,
you should characterize the problem
by determining the levels
and frequencies of the
desired and interfering signals,
the sensitivity and noise floor of the A/D converter,
etc.
Based on these measurements
determine the requirements of your design
in terms of
gain, noise figure, bandwidth, frequency accuracy and stability, etc.
Part 2: Initial Design
Once you have determined your design requirements,
return to
the previous section,
choose a receiver architecture,
select components for each of the functions,
and create a circuit diagram for your hardware
and a block diagram for your software.
Calculate required component values.
If necessary include regulators for required supply voltages.
Part 3: Assemble, Test, Repeat
Once your initial design is complete, select your prototyping
method
(see the
Prototyping
chapter for some examples),
order any required parts,
and begin assembling your system.
Unlike Exercise 4, this is not yet a proven design,
so it is even more important to assemble and test in sections.
In some cases failure will be due to an error in design
rather than an error in assembly.
In this case, return to the previous step
(at least for the subsystem in question)
create a new design, assemble, test, ....
Part 4: Characterization
Once your entire system is working correctly, it's time to verify
that it meets the design specifications.
Using the signal generator, oscilloscope, spectrum analyzer, and
Labview
as appropriate, measure the following performance characteristics of your board:
-
Freqency response of RF input filter.
-
Frequency response of IF output filter.
-
Gain from RF input to IF outputs.
-
Minimum detectable signal.
-
Dynamic range.
-
Image rejection.
-
SNR of received WWV signal.
-
Accuracy of digital time code signal.