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Re: [Discuss-gnuradio] Why 4 ADC's?
From: |
Jeff Brower |
Subject: |
Re: [Discuss-gnuradio] Why 4 ADC's? |
Date: |
Wed, 18 Jul 2007 15:12:17 -0500 |
Johnathan-
> > I assume this also true for the BasicRX daughterboard? (Doesn't do
> > downconversion, but does do analog multiplication to get I and Q?)
>
> Almost. The boards don't do anything with the signal, but have separate
> I and Q inputs that go to the ADCs as is.
>
> On the FPGA, however, there are digital mixers that you can use to
> convert a center frequency down to baseband, so you get a complex I and
> Q signal out of that, even if you only supply a signal to the I input.
> That is what is actually happening when you "tune" a BasicRX or LFRX board.
I think the OP is confused at what "signal processing" is happening on the RF
daughterboard. Although some recent posts have said "none", there actually is
some
-- filters to separate the I and Q signals which were summed at the point of
original
transmission to make a single airwave.
This is why the two ADCs are actually sampling separate, different signals, even
though their sampling rate clocks are synchronized.
-Jeff
- [Discuss-gnuradio] Why 4 ADC's?, Ian Larsen, 2007/07/17
- Message not available
- Re: [Discuss-gnuradio] Why 4 ADC's?, Ian Larsen, 2007/07/18
- Re: [Discuss-gnuradio] Why 4 ADC's?, Roshan Baliga, 2007/07/18
- Re: [Discuss-gnuradio] Why 4 ADC's?, Johnathan Corgan, 2007/07/18
- Re: [Discuss-gnuradio] Why 4 ADC's?,
Jeff Brower <=
- Re: [Discuss-gnuradio] Why 4 ADC's?, Roshan Baliga, 2007/07/18
- Re: [Discuss-gnuradio] Why 4 ADC's?, Jeff Brower, 2007/07/19
- Re: [Discuss-gnuradio] Why 4 ADC's?, Johnathan Corgan, 2007/07/19
- Re: [Discuss-gnuradio] Why 4 ADC's?, Jeff Brower, 2007/07/19
- Re: [Discuss-gnuradio] Why 4 ADC's?, Eric Blossom, 2007/07/19
- Re: [Discuss-gnuradio] Why 4 ADC's?, Jeff Brower, 2007/07/19
- Re: [Discuss-gnuradio] Why 4 ADC's?, Ian Larsen, 2007/07/18
- Re: [Discuss-gnuradio] Why 4 ADC's?, Jeff Brower, 2007/07/19