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Re: [Discuss-gnuradio] Why 4 ADC's?
From: |
Johnathan Corgan |
Subject: |
Re: [Discuss-gnuradio] Why 4 ADC's? |
Date: |
Thu, 19 Jul 2007 06:30:57 -0700 |
User-agent: |
Thunderbird 1.5.0.12 (X11/20070604) |
Jeff Brower wrote:
> 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.
--
Johnathan Corgan
Corgan Enterprises LLC
http://corganenterprises.com
- [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 <=
- 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