Remove unused and experimental code.
Relaxed LCD smeter refresh rate (in order to reduce interference on RX).
Allow ADC/RX-TX setup times (wait long enough before enabling TX, and disable TX well before stopping ADC).
Added CPU benchmark for ISR processing during TX.
Added operational instructions.
Added performance measurements.
Cosmetic and usability changes.
In detail:
Reduced sample jitter by matching sampling rate to a multiple of OCR0A timer divider.
Unit angle now configurable and scalable so that full precision (of integer range) can be used to calculate phase differences; the unit angle is configured to be an exact multiple of the samp$
Hilbert transformer fixed bug, simplified and improved in precision (improved from -15dB to -40dB in an image rejection setting).
Arctan rounding errors reduced from approx. 5 degree to 0.8 degree.
Moved from 8 bit to 16 bit precision for audio input and I/Q values.
Microphone-input response now flat from 0-2200Hz (removed original high-pass filter with 20dB roll-off at 800Hz).
Experimental code (currently commented-out) for measuring phase differences between programmatically synchronised SI5351 clocks.
Fixed an issue where for every RX-TX transition a burst of random RF frequencies were emitted.
Improved precision of smeter, and found that disabling smeter prevent spurs leaking in from LCD data transfer into RXi (smeter still enabled).
Added a LUT-based pre-distortion algorithm that can be calibrated via an internal amplitude measurement.
Fixed issue with the envelope generation through Q6 impacting the IMD-performance, dynamic range, efficiency and thermal-stability; this fix REQUIRES the removal of C31 and increase of C32 to$
Fixed an issue where VOX was unintentially triggering TX by ADC noise leaking through key-shaping circuit, and simplied VOX algorithm.
Generaized PLL and MultiSynth algorithms and added experimental algorithm for setting a second frequency (via a different MS divider and where PLL is the same).
Experimental code for measuring the phase of the transmitted signal (via PA and QSD), this could give insight in antenna impedance and PA phase-response as function of amplitude.
guido