QCX+ SSB DSP decoder

Note: all files and sketches on M0IFA.me

Wow its works, boy does it work!

QCX+ and Teensy DSP SSB decoder

Teensy DSP Hilbert filters for QCX+ SSB reception

One possibility, to have the QCX+ able to receive LSB or USB SSB signals, is to wire out the I & Q signals from the Tayloe detector via a couple of 100nF capacitors... (Teensy audio input impedance is 30k so 100nf is enough for good LF response)

Tayloe Detector, I & Q outputs, wire up from QCX+ PCB

...to an external DSP SSB decoder. For example using a Teensy processor. This DSP can be programmed with a couple of Hilbert filters to give a narrow BW and +/-45deg phase shifts.

DSP processing

The code can be generated using the PRJC Audio library and their on-line designer. The full Teensy code for this application is TEENSY_QCX_100. The Teensy used in v3.2 with its Audio processor board, from PRJC,

Teensy 3.2

Audio board/shield

Simple wiring to the QCX, the Audio board output goes to an audio amp & LS

Teensy DSP SSB decoder, USB or LSB switchable

The circuitry could be built into the QCX case. The audio output can also be programmed to be by the Teensy USB connector if you want to feed it to a WSJT program running on your PC for FT8 reception.

Boxed up

This is it working with the QCX+

Switch down LSB, up USB