High-Precision Sine Wave Generator (USB-Controlled) – Prototype + Firmware + Analog Design

I am looking for a highly experienced embedded + analog design engineer to develop a high-precision sine wave generation system with real-time USB control. This is a result-driven project focused on delivering a working, validated prototype, not just schematics.

System Requirements
1. Sine Wave Generation
DDS-based solution (e.g., AD9833 or better alternative – developer may choose)
Frequency range: up to ~10 kHz (focus on stability, purity, low distortion)
Proper analog filtering required (low-pass)
2. Amplitude Control
Controlled via DAC (e.g., MCP4822 or equivalent – developer may choose)
Adjustable via PC interface (not continuously dynamic)
Stable and calibrated output expected
3. Offset Control (Critical Feature)
Real-time adjustable DC offset via USB interface
Update rate target: ~10 kHz
Smooth and predictable response (no major glitches)
4. Microcontroller
Preferred: Teensy 4.1 (or equivalent high-performance MCU)
Must handle:
USB communication (PC and MCU)
SPI communication (DDS + DAC on shared bus)
Deterministic timing for DAC updates
5. Analog Stage
Op-amp based summing / conditioning stage (e.g., NE5532 / OPA series or equivalent)
Must support:
DDS sine input
DAC-controlled offset
Amplitude scaling
Clean output with minimal distortion and noise
Dual supply (±V) design is allowed and preferred if required for performance
Key Deliverables (MANDATORY)
1. Working Prototype (Critical Deliverable)
Fully functional hardware prototype (breadboard or PCB acceptable)
Must demonstrate:
Stable sine wave output
USB-controlled offset behavior
Configurable amplitude
Live demonstration over video call is mandatory
Must show:
Real waveform on oscilloscope
Response to PC commands in real-time
2. Firmware
Complete source code (Arduino IDE compatible preferred)
Includes:
USB communication protocol
SPI control for DDS and DAC
Real-time offset update handling
Code must be clean, documented, and reusable
3. PC Interface (Basic UI)
Simple PC-side interface (any language: Python / C# / etc.)
Must allow:
Setting amplitude
Real-time offset control
No need for complex UI, functionality is priority.
4. Design Files
Complete schematic (DDS + DAC + analog stage)
Component selection with justification
Basic PCB/layout recommendations (optional but preferred)
5. Calibration Method
Clear method to map digital input → actual output voltage
Ensures repeatability and predictable behavior
Strict Requirements (Read Carefully Before Applying)
This is not a theory or design-only project
Payment will be released ONLY after successful live demo of working prototype
No intermediate milestones will be created or paid
Must be comfortable working with:
Mixed-signal systems (DDS + DAC + op-amp)
Real hardware debugging
Measurement validation (oscilloscope, etc.)
Preferred Expertise
Strong embedded development (Teensy / ARM / real-time systems)
Deep analog design experience (low-noise, signal conditioning)
Prior work in:
Function generators
Signal processing hardware
DDS/DAC-based systems
Screening Criteria (Strict Filtering)

Applications will be ignored if:
No relevant mixed-signal project experience is shown
Only software/firmware background without analog experience
No proof of hardware prototyping capability

Preference given to candidates who:
Share past project examples (preferably with waveforms or demos)
Demonstrate understanding of noise, distortion, and signal integrity
Can clearly explain their design approach upfront

Final Note
This project targets a semi-instrument-grade signal system.
Attention to detail, clean design, and real-world validation are critical.

If you are confident in delivering a working, tested prototype with both firmware and analog integrity, apply with your approach and past work.