DD4WH
Well-known member
I was wondering whether it would be possible to produce a high frequency square wave output (say in the range of 10kHz to 10MHz) with the Teensy 3.6. which is adjustable in frequency.
GOAL:
* a minimum-hardware software defined radio [SDR] with:
* Teensy as local oscillator (square wave: maybe from 10kHz to 10 MHz (or higher, if feasible ;-) )
* one IC mixer (direct conversion) mixing the RF signal with the Teensy produced LO signal down to audio baseband
* Teensy built-in ADC sampling the audio baseband signal at a sample rate of 8 or 16kHz
* Teensy DSP: producing IQ signals from the ADC mono input
* DSP demodulation running in the Teensy
* Teensy DAC output
The only external hardware would be one mixer IC (and some Rs and Cs for antialiasing and bypassing) and a buffer amp after the DAC for headphones.
The internal ADC and DAC would be set at a speed of 16ksps or 8ksps.
Now, my question would be:
Under these circumstances, would there be a possibility for the Teensy to produce a square wave with a duty cycle of 50%
adjustable in frequency from about 10Khz to 10MHz? That would eliminate the need for an external local oscillator for the mixer input. I would not need a sine, a square would be sufficient.
Maybe with the PWM functionality or the FrequencyTimer2 library?
Would be nice if somebody could point me in the right direction or provide a link (or tell me that this is a naive question and impossible to do with the Teensy )
All the best,
Frank DD4WH
GOAL:
* a minimum-hardware software defined radio [SDR] with:
* Teensy as local oscillator (square wave: maybe from 10kHz to 10 MHz (or higher, if feasible ;-) )
* one IC mixer (direct conversion) mixing the RF signal with the Teensy produced LO signal down to audio baseband
* Teensy built-in ADC sampling the audio baseband signal at a sample rate of 8 or 16kHz
* Teensy DSP: producing IQ signals from the ADC mono input
* DSP demodulation running in the Teensy
* Teensy DAC output
The only external hardware would be one mixer IC (and some Rs and Cs for antialiasing and bypassing) and a buffer amp after the DAC for headphones.
The internal ADC and DAC would be set at a speed of 16ksps or 8ksps.
Now, my question would be:
Under these circumstances, would there be a possibility for the Teensy to produce a square wave with a duty cycle of 50%
adjustable in frequency from about 10Khz to 10MHz? That would eliminate the need for an external local oscillator for the mixer input. I would not need a sine, a square would be sufficient.
Maybe with the PWM functionality or the FrequencyTimer2 library?
Would be nice if somebody could point me in the right direction or provide a link (or tell me that this is a naive question and impossible to do with the Teensy )
All the best,
Frank DD4WH
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