Hi Riho and Bob,
If I am not mistaken, the dynamic range of the loopback measurement in this
case may be limited by the DAC that happens to have noise about -106 dBA.
Another limiting factor is the maximum signal before clipping.
The important parameters for our SDR-1000 receivers are the noise and
clipping levels of the ADC. Almost all ADC's in higher class audio cards
with balanced input have reasonably low noise but the clipping level may be
too low. According to my measurements with Waveterminal 192X the clipping
level is +22 dBu and the noise at 24 kHz bandwidth is less than -103 dBu.
The measurements have been made with carefully balanced input and isolating
audio transformers at the input and output connections. Sorry, I don't have
the A-weighing filter.
Due to the home made signal generator and low noise instrumentation
amplifier I cannot guarantee the correctness of my measurement values, but
clearly the limitations seem to be on the SDR-1000 hardware side.
73, Ahti OH2RZ
----- Original Message -----
From: "rihob., es7aaz" <[EMAIL PROTECTED]>
To: <FlexRadio@flex-radio.biz>
Sent: Friday, September 23, 2005 7:15 PM
Subject: Re: [Flexradio] Audiocards, USB, etc.
Hi,
Bob:
Esi Juli unbalanced loopback @ 24-bit, 48 kHz mode:
http://www.hot.ee/es7aaz/Juli.htm
P.S. It was RMAA 5.4 when I did this measurement.
Rgds,
Riho, ES7AAZ.
