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<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: center" align=center><U><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB"><FONT face="Times New Roman">About the Dynamic Range of
Receivers<o:p></o:p></FONT></SPAN></U></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: center" align=center><B style="mso-bidi-font-weight: normal"><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB"><o:p><FONT face="Times New Roman"> </FONT></o:p></SPAN></B></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: center" align=center><B style="mso-bidi-font-weight: normal"><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB"><o:p><FONT face="Times New Roman"> </FONT></o:p></SPAN></B></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB"><FONT face="Times New Roman">The radio's <B style="mso-bidi-font-weight: normal"><I style="mso-bidi-font-style: normal">dynamic range for single tone
signals</I></B> is affected by the automatic gain control range (about 120 dB,
independant of ADC's dynamic range, even possible with an 8-bit
ADC).<o:p></o:p></FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB"><o:p><FONT face="Times New Roman"> </FONT></o:p></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB"><FONT face="Times New Roman">It has nothing to do with the instantaneous dynamic
range, which is defining the radio's capabilty to discern a weak signal (near
the noise floor) in the presence of a much larger signal. The maximum possible
ratio of the two signal's levels is called <B style="mso-bidi-font-weight: normal"><I style="mso-bidi-font-style: normal">instantaneous dynamic
range</I></B>).<o:p></o:p></FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB"><o:p><FONT face="Times New Roman"> </FONT></o:p></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB"><FONT face="Times New Roman">The overall instantaneous dynamic range of the receiver
is not limited by the nyquist dynamic range of the 16-Bit ADC (about 95 dB). DSP
is decimating the ADC sampling rate from 100 kS/sec down to rates appropriate to
the actual CW / SSB signal bandwidths of 300 / 3000 Hz (meaning
F<SUB>s</SUB>= 781 / 12.5 kS/sec). Noise coming from ADC (including the
quantization noise) is reduced by just the ratio of ADC's nyquist bandwidth (=50
kHz) to the signals bandwidth, thus giving a corresponding gain in dynamic range
of <o:p></o:p></FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB"><o:p><FONT face="Times New Roman"> </FONT></o:p></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman"><IMG SRC="cid:X.MA1.1154599002@aol.com" height=44 width=336 v:shapes="_x0000_s1026" DATASIZE="789" ID="MA1.1154599002" ><BR style="mso-ignore: vglayout" clear=all><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB">Together
we are getting a total dynamic range<SUB>ADC</SUB> of about 117 dB [CW] and 107
dB [SSB];.<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB"><o:p><FONT face="Times New Roman"> </FONT></o:p></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB"><FONT face="Times New Roman">[Note, that the instantaneous dynamic is not only limited
by ADC' noise behaviour, but also by the synthesizer's phase noise
characteristic; the lower the signal bandwidth, the more impact the synthesizer
will have on the dynamic]<o:p></o:p></FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB"><o:p><FONT face="Times New Roman"> </FONT></o:p></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB"><FONT face="Times New Roman">The behavior of a real radio exposed to large signals
spreaded over several overcrowded broadcast bands is characterized best with a
measure for a multi tone dynamic range like the <B style="mso-bidi-font-weight: normal"><I style="mso-bidi-font-style: normal">two
tone intermodulation free dynamic range.</I></B> This is indirectly affected by
the radio's noise figure and the well known two tone intermodulation's intercept
point (of second and third order), IP2 / IP3.<o:p></o:p></FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB"><FONT face="Times New Roman">Two tone intermodulation distortions are measured for the
two unwanted signals being signal out of band or being both in band to separate
the behaviour of the radio's RF parts on the one hand and that of the IF/AF
parts on the other hand.<o:p></o:p></FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB"><FONT face="Times New Roman">Care must be taken to distinguish between the
intermodulation distortions of the IF path and the
intermodulation / harmonic distortions of the audio path
!<o:p></o:p></FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB"><o:p><FONT face="Times New Roman"> </FONT></o:p></SPAN></P>
<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN lang=EN-GB style="FONT-SIZE: 14pt; mso-bidi-font-size: 10.0pt; mso-ansi-language: EN-GB"><FONT face="Times New Roman">In band intermodulation behaviour may be influenced by
the automatic gain control's state and thus be nonlinearly dependent on input
level.<o:p></o:p></FONT></SPAN></P></DIV></FONT></BODY></HTML>