How tahmid-mahmud-fahim/pcb-amplitude-modulator works
1. Repository type
- This is an Altium Designer PCB project for an analog AM (amplitude modulation) circuit. It is not a software application; the source of truth is the schematic and PCB layout files.
2. Top-level structure
- Problem_2.PrjPcb is the project container that links the design artifacts.
- Problem_2.SchDoc is the electrical schematic.
- Problem_2.PcbDoc is the physical PCB layout.
- README.md documents the intended circuit and shows schematic/board renderings.
3. Functional architecture
- The design is split into two main analog subsystems:
- an AM generator stage
- an amplifier stage
- The README states these are implemented with two inverting op-amp amplifiers, so the circuit is centered on analog signal conditioning rather than digital control.
4. Signal flow
- The message signal Vm and carrier signal Vc are provided externally from a signal generator.
- These inputs feed the AM generator portion of the circuit.
- The resulting modulated signal is then passed through the amplifier stage.
- The final AM output is intended to be observed on an oscilloscope.
5. Schematic boundary
- SchDoc defines the logical connectivity: component symbols, nets, and the relationships between the op-amp stages and I/O.
- This is where the modulator’s functional behavior is captured independently of board placement.
6. PCB boundary
- PcbDoc defines the physical realization: component placement, trace routing, board outline, and copper layers.
- The repo includes both a 2D board view and a 3D view, indicating the layout is meant to be inspected as a manufacturable board, not just a conceptual schematic.
7. External interfaces
- The circuit is designed to connect to lab instrumentation, not embedded firmware:
- input: signal generator for Vm and Vc
- output: oscilloscope for the AM waveform
- Any power input is not described in the README, but the op-amp-based architecture implies a required analog supply boundary.
8. Design intent
- The repository’s goal is to demonstrate the practical implementation of AM modulation in hardware.
- The key architectural concern is preserving the analog signal path from input generation through modulation and amplification to the output test point.
9. Project-level dependency chain
- The project file ties the schematic and PCB together, meaning the normal flow is:
- define circuit in SchDoc
- transfer/netlist into PcbDoc
- validate by comparing physical layout against the schematic
- There are no source-code modules, build scripts, or runtime services beyond the EDA project itself.
10. What to diagram
- A correct architecture diagram would show:
- external signal sources (Vm, Vc)
- AM generator block
- amplifier block
- AM output to measurement equipment
- schematic-to-PCB design artifact boundary
- The repository is fundamentally a single-board analog signal-processing design with documentation and layout artifacts.
Main entry points: Problem_2.SchDoc Schematic · Problem_2.PcbDoc PCB layout · Problem_2.PrjPcb Project · README.md README
Components 9
EDA artifacts
Project, schematic, PCB, and documentation files
- Project · Links the schematic and PCB design artifacts
Problem_2.PrjPcb - Schematic · Defines component symbols, nets, and AM stage connectivity
Problem_2.SchDoc - PCB layout · Physical placement, routing, and board realization
Problem_2.PcbDoc - README · Describes the intended AM circuit and shows renders
README.md
Analog signal path
Functional AM generation and amplification blocks
- AM generator · First inverting op-amp stage that produces the modulated signal
- Amplifier · Second inverting op-amp stage that boosts or conditions the AM waveform
Lab I/O
External signal sources and measurement equipment
- Vm input · External message input from a signal generator
- Vc input · External carrier input from a signal generator
- AM output · Final modulated signal observed on an oscilloscope
Connections 9
- Project → Schematic: defines · Project references the schematic as the logical source
- Project → PCB layout: defines · Project references the PCB as the physical board
- README → Schematic: describes · Documentation explains the intended circuit behavior
- README → PCB layout: shows · Documentation includes schematic and board renderings
- Vm input → AM generator: feeds · Message signal enters the modulator stage
- Vc input → AM generator: feeds · Carrier signal enters the modulator stage
- AM generator → Amplifier: passes to · Modulated signal is sent to the amplifier stage
- Amplifier → AM output: drives · Final AM waveform is routed to the measurement output
- Schematic → PCB layout: transfers to · Logical design is realized as board layout