644 16 Mic Beamformer
644 : 16 Mic Beamformer
- Author: Armaan Gomes
- Description: A 0 delays fixed delay and sum beamformer that can utilize up to 16 input microphones
- GitHub repository
- Open in 3D viewer
- Clock: 0 Hz
How it works
The 16 Microphone Beamformer performs delay and sum beamforming on 16 microphones and outputs an I2S stream for easy processing. First the microphone data is passed in through 8 input pins in DDR(Double Data Rate) format. From there the chip converts the data to SDR (Single Data Rate); 1 wire per microphone. The microphone data is then summed and passed through a 3-stage CIC (Cascading Integrator Comb) Filter to convert it from PDM (Pulse Density Modulation) format to PCM (Pulse-code Modulation). This is then outputted by a I2S bus.
How to test
1. Initial Setup
- Connect Power Supply
- Ensure the module is correctly powered
- Connect Clocks
- Connect a
3.072Mhzclock tobit_clk(uio_in[0]) - Connect a
48khzclock tolr_clk(uio_in[1]) - Ensure both clocks are aligned
- Connect a
- Connect Microphones
- For each microphone, connect their
VCCandGNDpins to their respective sources - Connect their
clkpin to a3.072Mhzclock - Configure left/right pairs such what there are 8 of each type.
- For each left-right pair, combine their data wires (through a bread board for example) and connect them to
ui_in. Order does not matter.
- For each microphone, connect their
- Connect I2S reciever
- Connect an I2S reciever of your choice like a configured Raspberry Pi or supported speaker to the
outpin (uo_out[0])
- Connect an I2S reciever of your choice like a configured Raspberry Pi or supported speaker to the
Monitor Output
- Procedure
- Enable I2S reciever
- Enable Clock Signals
- Record data from I2S reciever (Varies based on chosen reciever)
External hardware
You need 16 digital microphones, a clock generator (can be a raspberry pi, microcontroller, etc.), and something that recieves the I2S output (this can be a rapberry pi or most auido output devices).
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | PDM Input Mics 0,1 | I2S Out | Bit Clock (3.072 MHz) |
| 1 | PDM Input Mics 2,3 | LR Clock (48kHz) | |
| 2 | PDM Input Mics 4,5 | ||
| 3 | PDM Input Mics 6,7 | ||
| 4 | PDM Input Mics 8,9 | ||
| 5 | PDM Input Mics 10,11 | ||
| 6 | PDM Input Mics 12,13 | ||
| 7 | PDM Input Mics 14,15 |