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Re: [Discuss-gnuradio] Why 4 ADC's?
From: |
Jeff Brower |
Subject: |
Re: [Discuss-gnuradio] Why 4 ADC's? |
Date: |
Thu, 19 Jul 2007 09:37:26 -0500 |
Johnathan-
> > The LFRX has two separate antenna inputs, supplied to Vin-A and
> > Vin-B. These are not I-Q data. USRP board FPGA logic would apply
> > one mixer or two (30 MHz or less).
>
> [...]
>
> > The RFX2400 mixes with a 2.4 GHz osc and creates one set of I-Q 65
> > MHz range signals, +/-I on Vin-A and +/-Q on Vin-B. To get baseband
> > signals, the logic has to apply two mixers.
>
> The FPGA DDC logic uses a single but *complex* mixer to do frequency
> conversion of the signal from the ADCs. That is, it treats the data
> from Vin-A and Vin-B as a complex number in I and Q format, and
> multiplies this complex number by a complex sinusoid of a configurable
> frequency. This is very different from having two mixers.
Yes thanks for that correction. That's accurate for RFX2400. For the LFRX
Vin-A and
Vin-B are treated as separate RF inputs and not a combined I-Q data set.
-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, 2007/07/18
- 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 <=
- 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