M5Unified_CW_Decoder

Description:

Ported Android CW Decoder made by OZ1JMH to M5Unified (M5Core2). M5Core2 has a built-in microphone and a 2” LCD, making it perfect for CW decoder by itself.

When the parameters are adjusted for built-in microphne, it works very comfortably.

• Supports M5Unified (M5Core2).

• Convert Goertzel algorithm to fixed-point arithmetic operations.

• Visualize detection magnitude.

• Morse tape printing function.

• Automatic Gain Control for microphone.

• Checked with Arduino IDE 2.3.2, M5Unified 0.1.17 and esp32 3.0.5

• Since it is coded in M5Unified, it should be easy to port to other models in M5Stack.

• Video

This program is a modified version of "OZ1JHM CW Decoder VER 1.01", originally developed by Hjalmar Skovholm Hansen OZ1JHM.

Files

• M5Unified_CW_Decoder.ino
  • Modified from OZ1JHM decoder11.ino.
• m5un.[ch]pp
  • M5Core2 program with M5Unified library.
• basic_op.[ch]
  • Signal processing basic operators, Compatible with ITU-T G.191 Software tools.
• bilinear.[ch]
  • Bilinear tranfomation method for converting to digital transfer function from analog transfrer function.
• f2q.h
  • Converting floating-point value to Q.n fixed-poing value macros.
• filter.[ch]pp
  • 1st and 2nd order fixed-point IIR digital filter classes.
• agc.[ch]pp
  • Automatic Gain Control class.
• goertzel.hpp
  • Goertzel algorithm class with fixed-point arithmatic operation.

ToDo

• Automatic tone frequency tracking function.
• Microphone AGC maximum gain adjustment feature.
• Support for Japanese Morse code