654 CEJMU WSPR Encoder
654 : CEJMU WSPR Encoder
- Author: Matthias Jung DL9MJ, Jonathan Hager DK7JH
- Description: WSPR encoder that takes call, locator and power and outputs a PWM that can be used for transmitting the WSPR symbols.
- GitHub repository
- Open in 3D viewer
- Clock: 56000000 Hz
How it works
Please see the documentation PDF in this repo that will be uploaded after the submission for more detailed info!
The design is programmed using UART. You may use the Python script in this repo. WSPR only needs the callsign, locator and transmit power, which is then turned into an array of 162 symbols. The transmission is achieved with a 4-FSK. The frequency for each symbol can also be programmed using UART.
How to test
Run the Python script to set the registers and then set start_transmission to 1. The chip will output sine and cosine with a PWM that can be turned into a proper sine/cosine by using a low-pass filter. The iq output signals should be used together with the TinyWhisper analog project on this shuttle or alternatively by providing the filters extra.
External hardware
You somehow need to convert the serial data produced by Python to UART. You may use a simple USB-UART bridge.
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | UART rx (115200 baud) | encoding_valid (indicates that start_transmission may be pressed) | ix (output) |
| 1 | start_transmission | cos_pwm | current symbol[0] |
| 2 | unused | cos_pwm_neg | current symbol[1] |
| 3 | unused | sin_pwm | unused |
| 4 | unused | sin_pwm_neg | unused |
| 5 | unused | i | unused |
| 6 | unused | q | unused |
| 7 | unused | ix | unused |