Real-Time Dual-Channel Oscilloscope & Audio Spectrum Analyzer

A high-performance, dark-mode real-time Dual-Channel Oscilloscope and Audio Spectrum Analyzer software stack running natively on PYNQ Linux platforms.

Features simultaneous dual-channel continuous analog acquisition on Arduino header pins A0 (Vaux1) and A1 (Vaux9), FPGA-accelerated anti-aliasing audio decimation ($50,\text{kSPS}$ audio rate / $40.96,\text{ms}$ window), sub-sample trigger phase-locking, dedicated passive microphone instruments (AudioDashboard), high-resolution audio FFT ($\Delta f \approx 24.41,\text{Hz}$) with sub-Hertz quadratic pitch tracking, and non-blocking dual-channel analog waveform generation with the Digilent Analog Discovery 3 (AD3) via pydwf.

🏛 System Architecture

This repository adopts the canonical PYNQ Custom Overlay pattern (OscilloscopeOverlay). It automatically pulls its compiled hardware bitstream and metadata from GitHub Releases (or loads local custom .bit builds) and encapsulates the Dual DMA receivers, AXI-Lite trigger registers, sequencer controls, and dual-wavegen into a unified Python object.

 [ Analog Discovery 3 ] ──(W1: Yellow)──────> [ PYNQ-Z2 Pin A0 (Vaux1) ]
 [      Wavegen       ] ──(W2: Yellow/White)─> [ PYNQ-Z2 Pin A1 (Vaux9) ]
 [         OR         ]                                       │
 [ MAX4466 Mics A0/A1 ]                       (XADC Dual Continuous Sequencer)
        │                                                     │ (1 MSPS Interleaved Stream)
  (pydwf SDK)                                                 ▼
        │                                            [ axis_trigger_unit IP ]
        ▼                                            (Selectable Trigger Source: A0/A1)
 [ AD3SignalGenerator ]                                       │ (Gated Stream)
 (Concurrent W1 & W2)                                         ▼
                                                     [ axis_decimator IP ]
                                                  (M = 10x Anti-Aliasing Averaging)
                                                              │ (50 kSPS Audio Stream)
                                                              ▼
                                                     [ tlast_generator (2048 pts / 40.96 ms) ]
                                                              │
                                                     [ axis_broadcaster ]
                                               ┌──────────────┴──────────────┐
                                               ▼ (40.96 ms Time Stream)      ▼ (Signed Stream w/ DC Block)
                                      [ AXI DMA 0 (Time) ]          [ xfft (2048-pt BFP) ]
                                               │                             │ (Δf = 24.41 Hz)
                                               │                    [ CORDIC (Magnitude) ]
                                               │                             │
                                               │                    [ AXI DMA 1 (FFT) ]
                                               │                             │
                                               └──────────────┬──────────────┘
                                                              ▼
                                                   [ OscilloscopeOverlay ]
                                            ├── .trigger          (HardwareTrigger AXI-Lite)
                                            ├── .xadc             (StreamingXADC DMA Driver)
                                            ├── .fft              (StreamingFFT PL DMA Driver)
                                            ├── .wavegen          (AD3SignalGenerator Dual-DAC)
                                            ├── .dashboard()      (AD3 Laboratory Scope UI)
                                            └── .audio_dashboard()(Dedicated Passive Microphone UI)

🖥 Interactive Dashboards

1. Dedicated Microphone & Audio Instrument (ol.audio_dashboard())

Designed specifically for passive MAX4466 electret microphones (or any analog audio sensor on pins A0 and A1), running completely independently without requiring an AD3:

• $40.96,\text{ms}$ Audio Timebase: Displays multi-cycle acoustic waveforms for speech, musical instruments, and bass frequencies ($50,\text{Hz} - 250,\text{Hz}$).
• Live VU Meters & Clipping Alerts: Status bar indicators that flash red if either microphone saturates ($V < 0.10,\text{V}$ or $V > 3.10,\text{V}$).
• Sub-Bin Quadratic Peak Pitch Tracking: Extracts the dominant acoustic fundamental ($f_0$) with $\pm 0.5,\text{Hz}$ accuracy.

2. Laboratory Oscilloscope Instrument (ol.dashboard())

Runs concurrent non-blocking dual waveform generation with the Analog Discovery 3 (W1 & W2) and streaming oscilloscope analysis with live 5-period auto-ranging.

🔌 Hardware Setup & Wiring

Option A: Dual MAX4466 Microphones (Acoustic Audio Mode)

Option B: Analog Discovery 3 (Signal Generator Mode)

🚀 Quick Start & Installation

1. Install Package from PyPI

pip install --upgrade pynq-oscilloscope

2. Copy Example Notebooks to Jupyter Workspace

pynq-oscilloscope-get-notebooks

💻 Python API Usage

Launch Interactive Microphone Audio Dashboard

from pynq_oscilloscope import check_usb_permissions, OscilloscopeOverlay

check_usb_permissions()

# Automatically loads v1.4.0 overlay and programs FPGA
ol = OscilloscopeOverlay()

# Launch dedicated dark-mode Audio & Microphone Instrument
app = ol.audio_dashboard()

Programmatic Dual-Channel Capture

from pynq_oscilloscope import OscilloscopeOverlay

ol = OscilloscopeOverlay()

# Configure Trigger: Trigger on Channel 1 (A0) Rising Edge @ 1.65V
ol.trigger.configure(mode="Auto", edge="Rising", source="CH1", threshold_volts=1.65)

# Synchronously capture both channels (1024 samples per channel @ 50 kSPS, 40.96 ms window)
v_a0, v_a1 = ol.capture_stereo()
print(f"Captured A0 Vpp: {v_a0.max()-v_a0.min():.2f} V | A1 Vpp: {v_a1.max()-v_a1.min():.2f} V")

ol.close()

📓 Notebook Suite

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.