System Bus Radio for Apple Silicon (M1/M2/M3)

This implementation is specifically optimized for Apple Silicon (M1/M2/M3) chips, which have strict power management and thermal throttling that can interfere with traditional memory bus noise generation.

Why a specialized version?

Standard implementations that hammer the memory bus continuously are quickly detected by the macOS power management unit (PMU) as "runaway processes." This results in:

• Thermal throttling (clock speed reduction).
• Process prioritization penalties (moving to efficiency cores).
• Signal loss after a few seconds of playback.

Solution: Pulse-Packet Modulation

This implementation uses a "Pulse-Packet" strategy:

1. Burst Transmission: It blasts the memory bus with 4 parallel threads (utilizing all P-Cores) for short durations (e.g., 20ms).
2. Micro-Sleep: It forces a tiny sleep (e.g., 0.5ms) between bursts.

This intermittent load tricks the PMU into thinking the process is behaving normally, allowing sustained high-power transmission without throttling.

Hardware Setup (Tested Configuration)

• Computer: MacBook Air (M1, 2020)
• Radio: SONY ICF-B99 (AM Receiver)
• Frequency: ~1100 kHz (1.1 MHz) - Note: This differs from the original 1580 kHz recommendation for Intel Macs.
• Antenna Position: Bottom center of the laptop (near the logic board).

Compilation & Usage

1. Compile the program:

   shCopy

   gcc -O3 main.c -o main
   

2. Run with a tune file:

   shCopy

   ./main ../../tunes/mary_had_a_little_lamb.tune
   

3. Important: For best results:

   • Keep your Mac plugged into power.
   • Close other heavy applications.
   • Tune your AM radio to ~1100 kHz (explore nearby frequencies for the strongest signal).