Message-ID: <4EDB97C2.5050106@usa.net>
Date: Sun, 04 Dec 2011 16:54:42 +0100
From: Alberto di Bene <dibene@usa.net>
User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:8.0) Gecko/20111105 Thunderbird/8.0
MIME-Version: 1.0
To: rsgb_lf_group@blacksheep.org
References: <E1RW9bG-0001fW-00.rn3aus-mail-ru@f214.mail.ru> <E1RWVQQ-00015Y-K7@post.thorcom.com> <CAA8k23RcqVfXC9MWoTWm9yESwuSG5ZP6fFFZA2y2j-C4f0DPHw@mail.gmail.com> <80A163C9035C44FBA23C7501118A6FDF@JimPC> <E1RWib5-0005lr-9o@post.thorcom.com> <CAA8k23T3MFrnUrj=ccAwOxEygb7cKfFVrcZPhMpEkaqU5Qs=Zg@mail.gmail.com> <E1RWv4C-00029S-4L@post.thorcom.com>
In-Reply-To: <E1RWv4C-00029S-4L@post.thorcom.com>
Z-USANET-MsgId: XID398PLDP3U0768X36
Subject: Re: LF: 16 bit vs 24 bit ADC?
Content-Type: multipart/alternative;
 boundary="------------030700000109060207000405"
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
X-AOL-SCOLL-URL_COUNT: 0  
x-aol-sid: 3039ac1db4074edb98107237
X-AOL-IP: 195.171.43.25
X-AOL-SPF: domain : blacksheep.org SPF : none


This is a multi-part message in MIME format.
--------------030700000109060207000405
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit

Bill,

  thanks for sharing your results about comparing 12- vs 16-bit QRSS reception.
You showed that, when the reception mode allows a very great reduction in the sampling rate,
going down in the mHz range, the processing gain thus obtained makes somewhat irrelevant
the finesse of the original amplitude resolution, when digitizing. And this was your original
question, which you have adequately answered to.  For this kind of applications, a 24-bit
sound card gives no practical advantages over a 16-bit one.

Just a note. This result cannot be generalized to SDR in its broader sense. If you cannot
dig into the noise with mHz resolution, but when what you want or need to achieve is e.g.
an SSB reception done with SDR technology, you cannot have a final sampling rate much lower
than, let's say, 8 kHz. In this case it is not possible to count on such a big processing gain.
It is for this kind of applications that 24 bits show an edge over 16 bits. When you need
a dynamic range of 120 dB in such a bandwidth, you badly need the more bits you can
obtain from your digitizer....

To mention still another English (or is this more American ?) proverb : YMMV
Your Mileage May Vary   :-)

73  Alberto  I2PHD


--------------030700000109060207000405
Content-Type: text/html; charset=windows-1252
Content-Transfer-Encoding: quoted-printable

<html>
  <head>
    <meta content=3D"text/html; charset=3Dwindows-1252"
      http-equiv=3D"Content-Type">
  </head>
  <body bgcolor=3D"#FFFFFF" text=3D"#000000">
    Bill,<br>
    <br>
    =A0 thanks for sharing your results about comparing 12- vs 16-bit QRS=
S
    reception.<br>
    You showed that, when the reception mode allows a very great
    reduction in the sampling rate,<br>
    going down in the mHz range, the processing gain thus obtained makes
    somewhat irrelevant<br>
    the finesse of the original amplitude resolution, when digitizing.
    And this was your original<br>
    question, which you have adequately answered to.=A0 For this kind of
    applications, a 24-bit<br>
    sound card gives no practical advantages over a 16-bit one.<br>
    <br>
    Just a note. This result cannot be generalized to SDR in its broader
    sense. If you cannot<br>
    dig into the noise with mHz resolution, but when what you want or
    need to achieve is e.g. <br>
    an SSB reception done with SDR technology, you cannot have a final
    sampling rate much lower<br>
    than, let's say, 8 kHz. In this case it is not possible to count on
    such a big processing gain.<br>
    It is for this kind of applications that 24 bits show an edge over
    16 bits. When you need<br>
    a dynamic range of 120 dB in such a bandwidth, you badly need the
    more bits you can <br>
    obtain from your digitizer....<br>
    <br>
    To mention still another English (or is this more American ?)
    proverb : YMMV<br>
    Your Mileage May Vary=A0=A0 <span class=3D"moz-smiley-s1"><span> :-) =
</span></span><br>
    <br>
    73=A0 Alberto=A0 I2PHD<br>
    <br>
  </body>
</html>

--------------030700000109060207000405--