Tag Archives: design


A phase-locked loop (PLL) frequency synthesizer design was completed by a student as their senior capstone project. The purpose of the project was to design a fractional-N PLL frequency synthesizer that could generate frequencies from 1-10 GHz with 1 MHz resolution. The PLL was designed to target an FPGA technology and optimize for low power consumption and small silicon area usage.

The student’s design utilized a charge pump based phase frequency detector (PFD) with current mode logic. A 5-bit prescaler and 12-bit digital controlled oscillator (DCO) were used to achieve the required frequency resolution. A 1 GHz VCO core was selected from a vendor IP library and properly interfaced to the DCO tuning input. Digital logic was designed to implement fractional-N frequency division with a modulus-N value up to 212. Extensive simulations were run in both post-layout and behavioral modes to verify the PLL could lock across the entire frequency range within the desired acquisition and settling times.

Power optimization techniques such as clock gating were applied throughout the design. Post-layout simulations showed the synthesized PLL core consumed under 100mW when locked. The student verified their design met all required specifications by fabricating an ASIC test chip. Measurements of the fabricated PLL showed it could successfully lock to any 1 MHz increment between 1-10GHz with acquisition times under 10us and steady state frequency drifts less than 1 ppm. The student’s project demonstrated an innovative fractional-N PLL design that achieved excellent frequency resolution and accuracy while optimizing for low power.

Another successful capstone project involved designing a charge pump PLL for clock and data recovery in serial data links. The student focused their project on high-speed interfaces operating at multi-gigabit data rates. They designed a charge pump PLL that recovered clocks from 4.25Gbps serial data streams. The core specifications for their PLL design were:

Frequency range: 3.5-5Gbps
Acquisition range: ±100MHz
Settling time: <250ns Reference frequency: 25MHz Technology: 45nm CMOS The student's PLL design utilized a multi-modulus divider in the feedback path to allow for integer-N operation across the entire frequency range. Their phase frequency detector and charge pump circuits were optimized for high-speed operation by employing current mode logic, short critical paths, and limiting parasitic capacitances. Feedback path filters were carefully sized to provide sufficient damping while minimizing phase margin degradation. Extensive simulations and pre-layout analysis were done to verify lock acquisition and tracking capabilities. Post-layout simulations showed the design could successfully recover clocks from data with bit error rates less than 1E-12. The design was fabricated as an independent verification vehicle through a silicon foundry.Chip measurements validated the PLL reliably locked onto data streams up to 4.5Gbps, meeting and exceeding the project goals and specifications. This successful student project demonstrated an innovative high-speed PLL design approach for serial data recovery applications. Another senior capstone project involved developing a low power fractional-N PLL for wireless transceiver applications. The student designed a wireless transmitter requiring a frequency synthesizer to generate output frequencies from 2.4-2.5GHz with 500kHz resolution to support protocols such as Bluetooth. Key specifications for their fractional-N PLL design included: Frequency range: 2.4-2.5GHz Frequency resolution: 500kHz Reference frequency: 25MHz Settling time: <500ns Technology: 65nm CMOS Power consumption: <100mW The student implemented a 7-bit delta-sigma modulator to realize fractional-N frequency division. An on-chip VCO was designed centered at 2.45GHz along with amplitude control circuitry. Feedback loops were optimized through pole-zero alignment techniques. Logic-based frequency switching was implemented to quickly switch output frequencies with glitch-free operation. An ASIC was fabricated in a Silicon On Insulator process. Measurement results showed the synthesized fractional-N PLL core consumed only 75mW while meeting the frequency resolution specification across the entire tuning range. Settling times were consistently below 400ns. The student demonstrated extensive characterization of frequency switching performance, phase noise, and amplitude control loop dynamics. This successful PLL design project showed innovation in realizing a low power fractional-N frequency synthesizer suitable for wireless transmitter applications. These examples demonstrate a few of the many successful PLL design projects completed by electrical engineering students as their capstone projects. Common themes included optimizing for power, speed, and accuracy while meeting rigorous specifications. Through innovative circuit techniques and verification planning, students were able to synthesize high performance PLL cores suitable for applications such as frequency synthesis, clock recovery, and wireless transmitters. These capstone projects exemplified the systems engineering skills gained through hands-on design experiences of realizing complex analog blocks like PLLs from concept to implementation.


A smart home automation system requires robust software at its core to centrally control all the connected devices and automation features in the home. The software design must be flexible, scalable and secure to handle the diverse set of devices that may be integrated over time.

At a high level, the software framework uses a client-server model where edge devices like smart lights, locks and appliances act as clients that communicate with a central server. The server coordinates all automation logic and acts as the single-point of control for users through a web or mobile app interface. It consists of several key components and services:

API Service: Exposes a RESTful API for clients to register, authenticate and send/receive command/status updates. The API defines resources, HTTP methods and data formats in a standard way so new clients can integrate smoothly. Authentication employs industry-standard protocols like OAuth to securely identify devices and users.

Device Manager: Responsible for registering new device clients, providing unique identifiers, managing authentication and enforcing access policies. It maintains a database of all paired devices with metadata like type, location, attributes, firmware version etc. This allows the system to dynamically support adding arbitrary smart gadgets over time.

Rule Engine: Defines automation logic through triggering of actions based on events or conditions. Rules can be simple like turning on lights at sunset or complex involving multiple IoT integrations. The rule engine uses a visual programming interface to allow non-technical users to define routines easily. Rules are automatically triggered based on real-time events reported by clients.

Orchestration Service: Coordinates execution of rules, workflows and direct commands. It monitors the system for relevant events, evaluates matching rules and triggers corresponding actions on target clients. Actions could involve sending device-specific commands, calling third party web services or notifying users. Logging and error handling help ensure reliable automation.

Frontend Apps: Provide intuitive interfaces for users to manage the smart home from anywhere. Mobile and web apps leverage modern UI/UX patterns for discovering devices, viewing live status, controlling appliances and setting up automations. Authentication is also handled at this layer with features like biometric login for extra security.

Notification Service: Informs users about automation status, errors or other home updates through integrated communication channels. Users can choose to receive push, email or SMS alerts depending on criticality of notifications. Voice assistants provide spoken feedback during automations for hands-free control.

Advanced Features
Home and Away Modes allow global control of all devices with a single switch based on user presence detection. Geofencing uses mobile phone location to trigger entry/exit routines. Presence simulation turns devices on/off at random to act like someone is home while away as a theft deterrent.

An important design consideration is scalability. As more smart devices are added, the system must be able to efficiently handle growing traffic, store large databases and process complex logic without delays or failures. Key techniques used are:

Microservices Architecture breaks major functions into independent, modular services. This allows horizontal scaling of individual components according to demand. Services communicate asynchronously through queues providing fault tolerance.

Cloud Hosting deploys the system on elastic container infrastructure in the cloud. Automatic scaling spins up instances when needed to handle peak loads. Global load balancers ensure even traffic distribution. Regional redundancy improves availability.

In-memory Caching stores frequently accessed metadata and state in high performance cache like Redis to minimize database queries. Caching algorithms factor freshness, size limits and hot/cold data separation.

Stream Processing leverages technologies like Kafka to collect millions of real-time device events per second, perform aggregation and filtering before persisting or triggering rules. Events can also be replayed for offline data analytics.

Secure communications between decentralized devices and cloud services is another critical design goal. Transport Layer Security (TLS) using industry-standard protocols like HTTPS ensures end-to-end encryption and data integrity. Military-grade encryption algorithms with rotating keys provide confidentiality.

Role-based access control prevents unauthorized access or tampering. Unique credentials, two-factor authentication and revocation of compromised tokens enhance security. Regular vulnerability scans and updates plug security holes proactively. Intrusion detection systems monitor traffic for anomalies.

An emphasis is placed on future-proofing the software through an adaptive, modular approach. Well-defined APIs and abstraction layers allow seamless integration of evolving technologies like AI/ML, voice, augmented reality etc. An plugin architecture welcomes third party integrations from ecosystem partners. The software framework delivers a future-ready connected home experience through its scalable, secure and extensible design.


Placemaking is a collaborative process by which we can shape our public realm in order to maximize shared value. Placemaking in the context of interior design focuses on improving the functionality and character of indoor spaces to cultivate meaningful experiences for users. A key goal of placemaking is to design spaces that promote community and culture. For an interior design capstone project, implementing principles of placemaking can help students design functional yet engaging spaces that serve the needs of various stakeholder groups.

One of the essential tenets of placemaking is understanding the historic and cultural context of a space and incorporating that context meaningfully into the design. For a capstone project, students should conduct in-depth research on the building, organization or community that will occupy the designed space. This includes understanding the mission and values of the occupants, as well as researching any historical or cultural significance of the location. By comprehending the deeper context, students can design spaces that authentically serve the needs and reflect the identity of the intended users.

For example, if designing a community center located in a historic building, students may choose to incorporate design elements that pay homage to architectural details from the original structure or local cultural artifacts. Or when designing an office, students could reference symbols or imagery meaningful to the company’s brand or activities. Integrating context ensures the designed spaces have relevance, meaning and resonance for stakeholders.

Another critical piece of placemaking for capstone projects is engaging stakeholders in the design process. Interior designers should seek input from various groups who will use the space, such as employees, volunteers, visitors, community leaders and more. This can be done through interviews, focus groups, surveys and design charrettes where stakeholders provide feedback on preliminary concepts. Gathering diverse perspectives helps ensure the space is adequately serving everyone and cultivates ownership over the final design.

Students must also evaluate how people currently use and move through similar existing places. This could involve on-site observations and mapping social behaviors. Understanding natural patterns of circulation and gathering provides key insights for the most functional and people-centered layout. For example, if observing many informal meetings occur in a hallway, the new design may purposefully allocate an open lounge area in that location.

Building on insights from research and stakeholder engagement, capstone placemaking projects then define a bold vision for how the designed space can nurture human experiences and interactions. For instance, the vision may emphasize creating an inspirational and collaborative workplace, or a warm and welcoming community hub. From this vision, various aspects of the physical design such as materials, lighting, furniture, color palettes, graphics and art are intentionally selected and composed to evoke the intended experience.

Signage, wayfinding and branding should raise awareness of available programs and resources to achieve effective activation of the space. Digital displays or bulletin boards can also promote a sense of community by highlighting user-generated content. Other tactics like hosting regular gatherings and rotating art exhibits encourage ongoing connection and evolution of the space over time.

Thoughtful consideration of how people of all demographics may interact within the space is also important for inclusivity and universal access. This includes following ADA accessibility guidelines but also performing inclusive design best practices like utilizing intuitive pictograms and varying seating types. Diversity and cultural sensitivity training aids students in designing for people of all backgrounds.

Implementing placemaking principles challenges interior design capstone students to conceive holistic projects that cultivate human well-being through the strategic design of functional and experiential indoor environments. By adequately involving stakeholders and leveraging contextual research, placemaking-focused designs manifest buildings and spaces that authentically serve communities and foster a greater sense of shared value amongst all users.


One project idea would be to redesign an existing building to make it more environmentally friendly and reduce its carbon footprint. The student could perform an energy audit of the building to analyze where energy is being lost or wasted. They would then develop plans to upgrade the building envelope through improved insulation, more efficient windows, and air sealing. Sustainable materials like bamboo, cork, or recycled content products could be specified for flooring, wall finishes, and furniture. Renewable energy systems like solar panels or a geothermal heat pump could also be proposed. The goals would be to significantly lower the building’s utility costs and decrease its environmental impact through reduced emissions.

Another option is designing the interior of a net-zero or living building. This would require an integrated design approach where the building’s systems, materials, and layout all work together to achieve net-zero energy, water, and waste metrics. Careful attention would need to be paid to daylighting, passive heating/cooling strategies, rainwater harvesting, composting toilets or greywater reuse systems. Sustainable materials like rapidly renewable bamboo or salvaged lumber from local deconstruction projects could feature prominently. Furnishings might be specified to use recycled plastic, aluminum, or post-consumer waste content. Living roofs or walls may also be proposed to benefits like stormwater management, reduced urban heat island effect, and improved biodiversity.

A third potential capstone could involve consulting for a business or organization to make their office space more environmentally friendly and help advance their sustainability goals. The student would conduct an audit of current resource usage, waste streams, commuting patterns, and purchasing policies. They would then develop a strategic plan with specific recommendations in areas like improved recycling and composting facilities, procurement of sustainably sourced and third-party certified products, installation of renewable energy or EV charging, enhancedreuse/redistribution of furnishings and equipment at the end of useful life, and more. Behavioral programs and signage could support utilization of these new systems and promotion of sustainable behaviors by occupants. Tracking and reporting metrics would allow ongoing evaluation of progress.

Developing interior designs for a green affordable housing project could provide another sustainability-focused capstone opportunity. Access to green and healthy living environments should not be constrained by income level. The student could partner with a nonprofit developer to plan multi-unit buildings using modular or mass timber construction for reduced costs. Thoughtful layouts optimized for daylight, cross-ventilation, and shared green spaces could enhance livability while limiting energy usage. Robust recycling stations, community gardens, electric car-sharing, and rainwater harvesting for landscape irrigation may be incorporated. Durable, non-toxic materials like bamboo- or cork-based flooring could specify. These designs could help address both environmental and social sustainability goals.

A capstone could also analyze the implementation of biomimicry principles within interior built environments. The student would research natural structures and processes that provide useful examples, such as termite mounds for passive cooling, hydrophobic lotus leaves for self-cleaning surfaces, or fast-growing bamboos for structural support. They may then design specific applications within interior spaces using biomimetic features, materials, or techniques to benefit areas like thermal regulation, air purification, water filtration, daylighting, or acoustic performance. Case studies could evaluate the human and environmental impacts of biomimicry approaches compared to conventional alternatives.

Interior design capstone projects focused on sustainability offer many valuable opportunities to design, consult, research, and prototype innovative solutions that can lower the environmental footprint of the built environment. Rigorous analysis, integrated systems thinking, and collaborative community partnerships are key components of impactful projects advancing both environmental and social sustainability through the discipline of interior design. With over 15,000 characters, I hope this overview provided ample detailed examples and discussion to suit the parameters of the question. Please let me know if any part of the answer needs further elaboration or clarification.


The ADDIE Model:

The ADDIE model is one of the most well-known and widely used frameworks for instructional design. It stands for Analysis, Design, Development, Implementation, and Evaluation. In the Analysis phase, instructional problems are identified and learning needs or goals are analyzed. In the Design phase, learning objectives, assessments and a test/curriculum plan are developed. The Development phase covers developing instructional materials like learner guides, instructor guides, simulations, etc. Implementation involves delivery of the instruction, which could be in a classroom, online, or blended. The Evaluation phase measures how effective the instructional material was at achieving the desired outcomes.

For a capstone project, students would identify an instructional problem, conduct a learner analysis, write objectives, develop materials and activities, propose an implementation strategy and evaluation plan. A strength of ADDIE is that it provides a very structured, systematic approach to instructional design. It may be considered too linear and rigid by some.


The ASSURE model is also a popular instructional design model used by many. It stands for Analyze learners, State objectives, Select methods/media/materials, Utilize methods/media/materials, Require learner participation, Evaluate and revise. In the Analyze learners phase, learner characteristics and context are analyzed. The State objectives phase involves stating measurable learning objectives. Select methods involves choosing delivery methods and instructional materials. Utilize methods is the development and delivery of instruction. Require participation engages learners in the instruction. Evaluate and revise assesses effectiveness of instruction and makes improvements.

For a capstone using ASSURE, students would go through each step to design, develop and propose an instructional intervention. It provides structure but is more flexible than ADDIE. Evaluation and revision are explicitly built into the model which is a strength. It does not provide as much detail on some phases compared to ADDIE.

Dick and Carey Model:

The Dick and Carey model is another widely respected instructional design model originally developed in the 1970s. It involves 10 main steps: (1) Identify instructional goals, (2) Conduct instructional analysis, (3) Analyze learners and contexts, (4) Write performance objectives, (5) Develop assessment instruments, (6) Develop instructional strategy, (7) Develop and select instructional materials, (8) Design and conduct formative evaluation, (9) Revise instruction, and (10) Design and conduct summative evaluation.

Some key aspects that are beneficial for a capstone project include the emphasis on both formative and summative evaluation built into the framework. This allows students to pilot and refine their instructional materials based on evaluation feedback. The model also provides more guidance on developing assessment instruments compared to ASSURE or ADDIE. Drawbacks could include it being more complex than ADDIE with additional steps and processes.

The Successive Approximation Model (SAM):

The SAM model involves an iterative, cyclic approach for designing and developing instruction. It includes the core steps of: (1) Set goals, (2) Conduct needs assessment, (3) Write objectives, (4) Develop evaluation instruments, (5) Develop instructional strategies, (6) Develop and select content, (7) Select delivery system, (8) Develop assessment, (9) Revise instruction based on assessment, (10) Implement, and (11) Repeat the cycle.

What’s beneficial about SAM for a capstone is that it emphasizes the instructional design process as ongoing and continually improved through feedback during implementation, unlike linear models like ADDIE. Students will get to practice the skill of revising and refining their instruction through multiple iterations based on assessed outcomes. It may lack some structure and specifics compared to models like Dick and Carey. It places more emphasis on the process than specific outputs.

All of these frameworks could be suitable options for an instructional design capstone project. The best choice would depend on the learning objectives, scope and available time/resources. Combining aspects from different models may also be an optimal strategy. The frameworks provide a systematic structure to follow while designing, developing and evaluating an instructional intervention for a given context and learning problem.