Pranavi Boyalakuntla Jonathan Kelley
In this paper, we leveraged introductory-level skills in analog-digital communication (ADC) to design an end-to-end communication system in Simulink. The Simulink model of the system was used to then select appropriate physical components and understand a potential hardware implementation. The ADC system model was designed to use Binary Phase Shift Keying (BPSK) as the modulation scheme and optimized to fit within a handful of real-world constraints including power limitations, transmission rate, error rate, and availability of components for the hardware implementation. The final result of the Simulink model demonstrated the capability for a transmitter and receiver to send digital messages to one another utilizing a custom packet encoding scheme.
This project served as an excellent demonstration of introductory ADC skills and helped better inform and relate these skills to real-world system design.
<aside> 💡 All code and schematic layup is available at https://github.com/jkelleyrtp/adc-bpsk-simulation
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Analog-to-digital and digital-to-analog communication techniques are the foundation of modern communication systems. Nearly every device used in today's society uses digital, programmable logic to control analog components that interact with real-world physics and limitations. These systems are ubiquitous - used everywhere from the networking the internet to connecting cell phones and enabling GPS.
Ultimately, the goal of such a system is to transmit a payload of data from one geographic zone to another. From there, system designers optimize for data rates, power requirements, security, and a whole host other relevant factors. For some systems, smoke signals might be adequate despite their limited range and limited bandwidth. For other systems, fiber optic cables and dedicated integrated circuits might be required to achieve system requirements.
For this project, we will be exploring a communication system designed to transmit digital payloads using radio frequency electromagnetic waves. As an academic exercise, the system will use binary phase shift keying (BPSK) as the modulation scheme, however we plan to implement a model flexible enough handle other frequency-shift-keying schemes. The ultimate goal for the system will be to transmit binary data between a receiver and transmitter, effectively laying the groundwork for a text-messaging system.
In order to properly bound the system designer parameters, we will be operating in the WiFi spectrum and roughly adhering to FCC regulations for WiFi. This means our carrier frequency will be 2.4 GHz. According to part 15 of the FCC rules [1],
"Maximum Effective Isotropic Radiated Power (EIRP) is 36 dBm (4 watt)"
The FCC also provides the table shown in Figure 1:
Figure 1. FCC Regulation Table.
It should be noted that these regulations inherently limit physical aspects of the system rather than the mathematical and theoretical inputs. Ultimately, our transmitter system will be limited by the power regulations and realistic values for WiFi antennas we can find available online. It should also be noted that system in this paper is relatively short-range with an emphasis on higher bandwidths, perhaps for sending large novels or watching Netflix.