[USRP-users] [Discuss-gnuradio] AGC and Dynamic Range of ADC

bob wole bnwole at gmail.com
Tue Sep 24 10:30:29 EDT 2013


On 09/23/2013 11:07 PM, bob wole wrote:

Can somebody please guide me on this ?

Bob


On Fri, Sep 20, 2013 at 4:44 PM, bob wole <address at hidden> wrote:

> I have USRPN210 with WBX and RFX2400. Is there any AGC chip on N210
> motherboard or WBX, RFX2400 before ADC to utilize the dynamic range of ADC
> ? if yes, which one? If not, then won't the varying input signal (for
> example signal from moving object)  to ADC affect the performance of ADC ?
>
> Bob
>

>>The ADC on an N210 has over 80dB of dynamic range.  If that >>isn't
enough, then your application can adjust the RF gain to taste.

>>Only a subset of applications actually benefit from the usual >>hardware
AGC schemes, and such schemes are invariably >>application-specific, so
there's
  >>no *automatic* gain control.  But your application can >>dynamically
make gain adjustments as it goes.


Hi Marcus thanks for response, If there is no automatic gain control then
how does it is ensured that ADC doesn't saturate ? I mean what if there is
a signal whose amplitude is greater that ADC's highest input level ?  Won't
it saturate the ADC ? Also what if the signal is too weak to span much of
the ADC input voltage, then again we are not using all bits effectively.
Guide please.

Thanks,

Bob

>>--
>>Marcus Leech
>>Principal Investigator
>>Shirleys Bay Radio Astronomy Consortium
>>http://www.sbrac.org
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