[Lowfer] Re: Phasing exciters : status update

[Alberto di Bene]

"John Andrews" <w1tag@charter.net> wrote:

> 800 Hz tone measured 805.4 Hz. THD was 0.025%. With no compensation between
> channels, the phase was 90 � 0.02 degrees.
>
> All tones tested between 53 Hz and 10 kHz had phase separations of 90 �
> 0.05 degrees.

John,
  many thanks indeed for your time. It should be possible to bring the 805.4 Hz
exactly to 800 by using the Frequency Calibration feature of the program, then
checking if the correctness of the frequency is maintained across the entire range.
If you have time, could you please also check in a couple of points also the 
Channel Skew Compensation ? Eg if you set the frequency at 5000 Hz (after frequency
calibration), moving the slider from -25.0 to +25.0 microsecond you should measure 
phase differences from 45 to 135 degrees. This would confirm the correctness of
the routine.

About PSK31, it is certainly possible to phase-modulate the generated signals, but
in my opinion this is beyond the purposes what TCube was written for. This without
taking into account my scarce knowledge of the PSK31 technical details.
Maybe a revised version of Jason, or better yet a new program could implement a
BPSK signaling scheme apt for weak signal work on LF.

73  Alberto  I2PHD