docs: update documentation for capture redesign and validation

README.md

@@ -11,22 +11,35 @@ The system implements a high-throughput signal chain in the FPGA (PL) and perfor
 ## Current Status
 
 - Tx subsystem: LFM pulse generator (DDS-based, complex output)
-- Rx subsystem: fully functional channelizer pipeline (PFB-based)
+- Rx subsystem: fully functional channelizer pipeline (PFB-based) or bypass
 - PL → PS interface: AXI4-Stream + DMA operational
-- PS processing: frame-based algorithm (RMS + peak detection)
+- PS processing: frame-based algorithm on a Data Process Window (DPW)
 
 ---
 
 ## System Architecture
 
-ADC → Channelizer (PFB, 512 bins)  
+Tx (PL)  
-→ FFT_Capture (frame control)  
+→ Waveform Generator (LFM / CW / Pulsed)  
-→ FIFO Serializer (4 FIFOs → 1 stream)  
+→ DAC  
-→ AXI4-Stream (uint64)  
+→ RF Loopback / Input  
+
+Rx (PL)   
+→ ADC  
+→ Channelizer (PFB, 512 bins) / Bypass / Counter  
+→ Capture (frame control)  
+→ AXI4-Stream (128-bit, 4 samples/clock)  
 → DMA (S2MM)  
 → PS Memory  
 → Processor Algorithm
 
+Post Processing (PS)  
+→ Triggered Capture  
+→ Sample Unpacking (I/Q)  
+→ Data Reshaping → [FrameSize x nFrames x nTriggers]  
+→ Host Communication / Processing / Visualization
+→ One DPW is a windows of FrameSize x nFrames samples
+
 ---
 
 ## Key Parameters

docs/pl_rx_subsystem.md

@@ -6,11 +6,9 @@
 
 ## Overview
 
-The Rx subsystem implements a **polyphase filter bank (PFB) channelizer** followed by FFT processing.
+The Rx subsystem implements a **polyphase filter bank (PFB) channelizer** followed by FFT processing, a **bypass path**, and a **multi-frame capture pipeline**.
 
-It converts wideband ADC input into frequency-domain channels and streams the result to the PS.
+It converts wideband ADC input into frequency-domain channels (or raw samples via bypass) and streams the result to the PS.
-
-A **bypass path** is also available for raw data inspection and debugging.
 
 ---
 
@@ -24,11 +22,9 @@ PFB Channelizer (Decimation + Filtering)
  ↓  
 FFT (512 bins)  
  ↓  
-FFT Capture
+Capture (frame control)  
  ↓  
-FIFO Serializer (4 → 1)
+AXI4-Stream (128-bit, 4 samples/clock)  
- ↓
-AXI4-Stream
  ↓  
 DMA
 
@@ -40,45 +36,26 @@ ADC
  ↓  
 Bypass Path  
  ↓  
-FIFO / Serializer
+Capture (frame control)  
  ↓  
-AXI4-Stream
+AXI4-Stream (128-bit, 4 samples/clock)  
  ↓  
 DMA
 
 ---
 
-## Bypass Functionality
+## Capture Pipeline
 
-The bypass allows direct observation of the input signal without channelization.
+- Multi-frame acquisition (configurable nFrames)
-
+- Frame size: 512 samples
-### Purpose
+- Supports asynchronous capture start (not frame-aligned)
-
+- TLAST asserted at frame boundaries
-- Debugging and validation
-- Access to raw ADC-domain data
-- Comparison with channelized output
-- Verification of downstream processing
-
----
 
 ### Behavior
 
-- Input data is routed directly to output
+- First frame may be partial
-- No filtering or FFT applied
+- Frames may contain ≤ 2 frame indices (expected)
-- Maintains same output interface (AXI4-Stream)
+- DPW spans nFrames frames but covers nFrames + 1 frame regions
-
----
-
-### Selection Mechanism
-
-A selector signal chooses between:
-
-- Channelizer output (normal operation)
-- Bypass output (raw data)
-
-Implementation typically uses:
-- Parallel paths
-- Output switching logic
 
 ---
 
@@ -86,22 +63,19 @@ Implementation typically uses:
 
 ### ADC Input
 - Sampling rate: 4096 MSPS
-- Data type: **fixdt(1,16,15)** (Q1.15 format)
+- Data type: **fixdt(1,16,15)** (Q1.15)
 
 ### PFB Channelizer
 - Decimation: 8
 - Effective bandwidth: 512 MHz
-- Input and internal scaling aligned to Q1.15 domain
 
 ### FFT
 - Size: 512
 - Produces frequency bins
 
-### FFT Capture
+### Capture
-- Controls frame boundaries
+- Defines frame boundaries (512 samples)
-
+- Generates TLAST
-### FIFO Serializer
-- Converts parallel streams into single stream
 
 ---
 
@@ -109,62 +83,57 @@ Implementation typically uses:
 
 ### System Standardization
 
-The signal chain was standardized to a **Q1.15 fixed-point format (fixdt(1,16,15))**:
+- End-to-end Q1.15 (**fixdt(1,16,15)**)
-
-- DAC output uses Q1.15
-- ADC input is reinterpreted as Q1.15 (Same Stored Integer)
-- Channelizer input operates in this normalized domain
-
----
 
 ### Channelizer Output Scaling
 
-- Native channelizer output: **sFix25_En23**
+- Native: **sFix25_En23**
-- Rescaled and quantized to: **fixdt(1,16,15)**
+- Quantized to: **fixdt(1,16,15)** (round + saturate)
-
-This conversion:
-
-- Preserves signal dynamic range
-- Maximizes fractional precision
-- Uses rounding and saturation
-- Aligns with system-wide numeric format
 
 ---
 
-### Data Width Reduction
+## Data Packing (Updated)
 
-- Previous format: **50 bits per complex sample** (25 bits real + 25 bits imag)
+- 4 samples per clock
-- New format: **32 bits per complex sample** (16 bits real + 16 bits imag)
+- Each sample: complex (16-bit real + 16-bit imag)
+- Packed into **128-bit AXI4-Stream word**
 
 Benefits:
-
+- Matches datapath parallelism
-- Reduced AXI bandwidth
+- Efficient DMA transfers
-- Reduced FIFO usage
+- Eliminates need for serializer stage
-- More efficient DMA transfers
 
 ---
 
 ## AXI4-Stream Output
 
-- Data type: uint32 (packed complex: 16-bit real + 16-bit imag)
+- Width: 128 bits
+- Contains 4 complex samples per cycle
 - TLAST = frame boundary
 
 ---
 
-## Data Format
+## Debug / Validation Features
 
-- Frame size: 512 samples
+A counter-based debug mode is implemented:
-- Complex samples packed into 32-bit words
+
+- Real part → sample counter (0..511)
+- Imag part → frame index
+
+Used to validate:
+- Sample continuity
+- Frame boundaries
+- DMA ordering and integrity
 
 ---
 
 ## Key Characteristics
 
 - Fully streaming pipeline
-- High throughput
 - Deterministic latency
-- Consistent fixed-point scaling (Q1.15 end-to-end)
+- High throughput (4 samples/clock)
-- Supports dual-mode operation (channelizer / bypass)
+- Dual-mode operation (channelizer / bypass)
+- Validated up to nFrames = 1024
 
 ---
 

docs/ps_subsystem.md

@@ -1,4 +1,4 @@
-# 🧠 PS Subsystem (Control + Processing)
+# 🧠 PS Subsystem (Control + Capture + Processing)
 
 [🏠 Project Home](../README.md)
 
@@ -8,73 +8,128 @@
 
 The PS subsystem is responsible for:
 
+- System initialization
 - Configuring PL subsystems
+- Triggering captures
 - Receiving data via DMA
-- Performing frame-based processing
+- Preparing data for processing and visualization
+
+The current implementation acts as a **placeholder for post-processing**, focusing on reliable data acquisition and host interaction.
 
 ---
 
 ## Responsibilities
 
-### Control
+### Control & Initialization
 
-- Writes parameters to PL registers:
+- Configure PL parameters:
-  - Tx generator configuration
+  - Tx waveform configuration
-- Generates TxPulseStart trigger
+  - Capture parameters (nFrames, etc.)
+- Initialize DMA and memory buffers
+- Manage system startup
+
+---
+
+### Trigger & Capture
+
+- Generates capture trigger (software-controlled)
+- Controls DPW acquisition timing
+- Each trigger initiates one DPW capture
 
 ---
 
 ### DMA Handling
 
 - AXI4-Stream → DMA (S2MM)
-- Data stored in PS DDR
+- Receives **128-bit stream** (4 samples per clock)
+- Stores data in PS DDR memory
 
 Configuration:
-- Frame size: 512
+- Frame size: 512 samples
-- Buffers: 16
+- nFrames: configurable (validated up to 1024)
 
 ---
 
-### Processing Pipeline
+## Data Format
 
-DMA → uint64[512]  
+### Raw DMA Data
-→ unpack real/imag  
+
-→ convert to complex  
+- Packed complex samples
-→ RMS + peak detection  
+- 16-bit real + 16-bit imag per sample
+- 4 samples per 128-bit word
+
+---
+
+### Processing Representation
+
+Data is unpacked and reshaped into:
+
+```
+[FrameSize x nFrames x nTriggers]
+```
+
+---
+
+## Processing Pipeline (Current)
+
+DMA  
+→ Unpack samples (I/Q separation)  
+→ Convert to complex representation  
+→ Reshape into 3D structure  
+→ Visualization / basic analysis  
+
+---
+
+## Validation Support
+
+Uses counter-based validation:
+
+- Real part → sample counter
+- Imag part → frame index
+
+Enables verification of:
+
+- Data continuity
+- Frame alignment
+- Correct ordering from DMA
 
 ---
 
 ## Execution Model
 
-- Event-driven (DMA trigger)
+- Triggered (event-based)
-- No buffering queue
+- Burst capture (DPW)
-- Frames may be dropped
+- Not continuous real-time streaming
 
 ---
 
 ## Performance Notes
 
-- Bottleneck: unpacking + conversion
+- Designed for correctness and validation (not optimized)
-- Cannot sustain full-rate input
+- Bottleneck: unpacking + data movement
+- Full-rate continuous processing not supported
 
 ---
 
-## Interaction with PL
+## Role in System
 
-### Tx Control
+The PS currently serves as:
-- Low-rate trigger (~Hz)
-- Starts burst generation
 
-### Rx Data
+- Control interface
-- Continuous high-rate stream
+- Data acquisition manager
+- Pre-processing stage
+
+Future implementations will replace the current processing with advanced algorithms (e.g., FrFT).
 
 ---
 
 ## Future Work
 
-- Replace processing with FrFT
+- FrFT-based processing
-- NEON optimization
+- Timestamp integration
-- Throughput improvements
+- UDP streaming
+- Optimization (NEON / vectorization)
+- Metadata extraction (move complexity to PL)
 
 ---