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Teensy-ConvolutionSDR

Software Defined Radio with the Teensy 3.6, the Teensy Audio board and any IQ-Quadrature Sampling Detector

Please find a detailed description of the hardware and software HERE.

This radio uses the Fast convolution approach to filter and process the radio signals with the floating point microprocessor Teensy 3.6

Hardware needed:

Teensy 3.6
Teensy Audio board
QSD = quadrature sampling detector and a local oscillator that can be tuned by I2C (eg. Si5351, Si570, Si514 . . .) [should run with Softrock, Elektor SDR (https://www.elektor.de/elektor-sdr-reloaded-150515-91), Fifi SDR and many others]
one encoder for frequency tuning
one pot for filter bandwidth
five pushbuttons
TFT display ILI9341-based
antenna for longwave/mediumwave/shortwave
5V power supply

Software:

Install Arduino
Install Teensyduino
Install a newer version of the ARM CMSIS DSP library and set it to use floating point (explained HERE: https://forum.pjrc.com/threads/40551-How-to-be-sure-I-m-using-the-FPU-in-T3-5-3-6?p=126193&viewfull=1#post126193)
Listen to the radio ;-)

Specifications at the moment:

Teensy 3.6 with audio board working in floating point
reception from about 12kHz to 30Mhz
FFT and inverse FFT with 4096 points using the new CMSIS DSP lib complex FFT function
filtering with 2049 tap FIR filter --> comparably steep filters are normally available in commercial receivers from 2000$ upwards ;-)
filter coefficients are calculated by the Teensy itself and the filter bandwidth can be chosen arbitrarily by the user
demodulation of AM, LSB, USB, pseudo-Stereo-USB, pseuso-Stereo-LSB (more to come . . .)
display up to 96kHz of frequency spectrum
Zoom into the spectrum for greater frequency resolution detail: built in with Frank Bösings code for sample rate change on-the-fly
superb audio quality (of course not like FM quality, but very good compared to other commercially available shortwave receivers)
needs about 50% of the processor ressources at 96ksps sample rate