Phase locked system design and measurement tutorial consisting of physical hardware and co-simulation environment

International Journal of Electrical Engineering Education,  Oct 2004  by Burbidge, Martin John

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* The course must provide the student with a practical working knowledge of PLL systems.

* The course must ease the student's assimilation of further advanced feedback system theory.

* The course must reinforce current control system knowledge through example and experimentation.

* Material must contain a significant hardware element, thus allowing students to carry out real measurements and experiments on electronic systems that are applicable to real-world applications.

* Material must contain a complementary set of simulation models that relate to the physical hardware system.

* The course must emphasise that simulations are not reality, and thus encourage the student to investigate the differences between the two domains.

* Material should identify basic functional hardware system checks that should always be carried out during system debugging.

* The course must provide an indication of behavioural modelling and simulation techniques related to phase locking and control systems.

* The course must provide students with examples of oscilloscope measurement techniques and oscilloscope to personal computer data connectivity options.

From the above requirements the material was split into two distinctive parts, consisting of a set of simulation models and background theory and a hardware evaluation platform, respectively. The developed hardware includes a set of accompanying notes that explains equipment set-up, and measurement procedures. In addition, technicians' notes and required components for each experiment are documented. Also, an appendix section is included that contains further set-up details and a cross-referenced schematic of the hardware demonstrator.

The resulting developed course material is designed to be used in the following manner. Initially, the student is expected to carry out the simulation aspect of the course remotely, prior to attending the lab-based sessions. The simulation part of the course is designed to be used in a web/internet-based teaching environment. During this phase the student is encouraged to modify various aspects of the simulation models and observe the results. Also, the student is expected to become familiar with the lab notes and appendices. Both the simulation and lab-based exercises allow the student to carry out general system-level characterisation experiments such as transient-step response monitoring and closed-loop transfer function monitoring. These types of experiments are also representative of those that would be used for design and evaluation of generic control systems. In addition, PLL specific tests are carried out, such as VCO (voltage controlled oscillator) gain and linearity, and openloop VCO noise-related measurements.

All of the above measurements can be carried out in both the simulated and real environment. However, results may differ slightly between the domains due to natural component deviations. The students are encouraged to investigate the perceived differences between measured and simulated results. Further measurements essential to hardware evaluation concentrate on typical system-level tests. These include power supply/component supply, voltage measurements, and basic signal frequency and voltage measurements. These aspects are not included in the simulation environment. A recommendation for ordering of the course material is given and is outlined as follows: