[Lowfer] Re: Sound card measurements

[Alberto di Bene]

"Lyle Koehler" <lyle@mlecmn.net> wrote:

> I tested three different sound cards by feeding the same 10 kHz signal to
> both left and right channels of the sound card's Line input, and recording a
> short .wav file in CoolEdit at a 48 kHz sampling rate.

[...]

Lyle, thanks for the detailed tests you have done. The plot thickens...  
it looks like both in input
and in output there must be the possibility to have an adjustable phase 
delay compensation
knob... probably this can be done acting just on the NCO, as the I/Q 
input signal is further
quadrature-downconverted using the software NCO. Must check the math to 
see that there
aren't catches...  any opinions or comments on this ?

> Another item for the wish list: Alberto, would it be possible to modify
> Spectran and/or Argo to accept two phase-quadrature input channels? If so,
> it would greatly simplify the design of a single sideband direct conversion
> receiver.


Hmmm, my to-do list is growing at an alarming rate...:-) I have also the 
request to split the audio
acquisition part from the processing and display part, linking the two 
with a TCP/IP connection...
I have added your request to the list, and probably it will take 
precedence over the TCP/IP stuff,
as it looks simpler to implement...:-)

73  Alberto  I2PHD