diff --git a/README.md b/README.md index 11229bf..352a49e 100644 --- a/README.md +++ b/README.md @@ -1,3 +1,5 @@ +GitHub last commit + # raspi-pico-aprs-tnc A TX-only [TNC](https://en.wikipedia.org/wiki/Terminal_node_controller) (Terminal Network Controller) to generate the [AFSK](https://en.wikipedia.org/wiki/Frequency-shift_keying#Audio_FSK) audio tones for [APRS](https://en.wikipedia.org/wiki/Automatic_Packet_Reporting_System) (Automatic Packet Reporting System) messages using a [Raspberry Pi Pico](https://en.wikipedia.org/wiki/Raspberry_Pi) microcontroller board. @@ -5,7 +7,7 @@ An analog line-out audio signal will be generated by a filter connected to GPIO- ![AFSK scope screenshot](https://github.com/eleccoder/raspi-pico-aprs-tnc/blob/main/doc/img/afsk_scope.png) -Image: Line-out signal (see below) probed by a DSO. We clearly see the 1200 Hz and 2200 Hz tones of the 1200 Bd 2-AFSK. +Image: Line-out signal (see [below](#Hardware)) probed by a DSO. We clearly see the 1200 Hz and 2200 Hz tones of the 1200 Bd 2-AFSK. Basically, the data/signal flow is as follows: @@ -60,4 +62,4 @@ The analog AFSK audio signal will be available at the filter's line-out. You can ## Ingredients / Acknowledgements - For APRS => AX.25 => PCM conversion I'm using [my modified version](https://github.com/eleccoder/ax25-aprs-lib) of [fsphil's ax25beacon](https://github.com/fsphil/ax25beacon) -- For PCM => PWM conversion I'm using the audio lib from [pico-extras](https://github.com/raspberrypi/pico-extras) (WARNING: maturity seems to be alpha/beta) \ No newline at end of file +- For PCM => PWM conversion I'm using the audio lib from [pico-extras](https://github.com/raspberrypi/pico-extras) (WARNING: maturity seems to be alpha/beta)