642 PDM Pitch Filter
642 : PDM Pitch Filter
- Author: Armaan Gomes
- Description: It uses a moving average filter and decimator to filter out a specific frequency
- GitHub repository
- Clock: 0 Hz
How it works
Explain how your project work This project pitch filters a microphone input stream. Because the bitstream is pdm (1 or -1 at 3.072 Mhz) a sine wave of certain frequencies has a certain length at which its average energy is 0. By making a moving average filter of that length we can eliminate that frequency and its harmonics
How to test
Connect a microphone to the pin and use the spi port to se thte decimator and filter length . Inprogress Explain how to use your project
External hardware
A pdm microphone spi input and clock generator List external hardware used in your project (e.g. PMOD, LED display, etc), if any
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | Bit Clock (3.072 Mhz) | PCM Out Mic 0 | Delay Select 0 |
| 1 | LR Clock (48Khz) | PCM Out Mic 1 | Delay Select 1 |
| 2 | PDM Input Mics 0,1 | PCM Out Mic 2 | Delay Select 2 |
| 3 | PDM Input Mics 2,3 | PCM Out Mic 3 | Delay Select 3 |
| 4 | PDM Input Mics 4,5 | PCM Out Mic 4 | Delay Select 4 |
| 5 | PDM Input Mics 6,7 | PCM Out Mic 5 | Beamformed PCM Output |
| 6 | PCM Out Mic 6 | Mic Clock | |
| 7 | PCM Out Mic 7 |