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Re: [Discuss-gnuradio] USB2 <-> fast ADC & DAC
From: |
Henrique Miranda |
Subject: |
Re: [Discuss-gnuradio] USB2 <-> fast ADC & DAC |
Date: |
Thu, 29 May 2003 02:38:09 +0100 (WEST) |
Hello Joseph,
(snip)
> If the IF signal to be captured is centered at 10.7MHz with a full
> bandwidth of 2MHz (+/-1MHz) then only a 4MSample/second acquisition
> rate is required not 23.4MSample/second ((10.7 + 1) * 2). The front
> end amplifier and track/hold devices must operate at the highest
> frequency but the ADC need not sample that high.
There is a small correction that ought to be made here. In your
calculations an undersampling restriction in being disregarded: the
signal spectrum must be fully contained in a Nyquist zone,
otherwise aliasing will occur!
In this case the minimum sample rate that can be used is
((10.7 + 1) / 2.5) = 4.68 Msps and the signal spectrum will be
placed in the fifth Nyquist region.
> If the IF signal to be captured is centered at 10.7MHz with a
> full bandwidth of 10MHz (+/-5MHz) then a 20MSample/second
> acquisition rate is required not 31.4MSample/second ((10.7 + 5) * 2).
31.4 Msps is really the minimum sample rate you can use in this
situation (1st Nyquist region) due to the same restriction.
Regards,
Henrique Miranda
- [Discuss-gnuradio] USB2 <-> fast ADC & DAC, Andy Green, 2003/05/27
- Re: [Discuss-gnuradio] USB2 <-> fast ADC & DAC, Paul A. Scott, 2003/05/27
- Re: [Discuss-gnuradio] USB2 <-> fast ADC & DAC, Joseph DiVerdi, 2003/05/27
- Re: [Discuss-gnuradio] USB2 <-> fast ADC & DAC,
Henrique Miranda <=
- Re: [Discuss-gnuradio] USB2 <-> fast ADC & DAC, Joseph DiVerdi, 2003/05/28
- Re: [Discuss-gnuradio] USB2 <-> fast ADC & DAC, Henrique Miranda, 2003/05/29
- Re: [Discuss-gnuradio] USB2 <-> fast ADC & DAC, Joseph DiVerdi, 2003/05/29
- Re: [Discuss-gnuradio] USB2 <-> fast ADC & DAC, Henrique Miranda, 2003/05/29
- Re: [Discuss-gnuradio] USB2 <-> fast ADC & DAC, Joseph DiVerdi, 2003/05/30
- [Discuss-gnuradio] Brooktree / Conexant video capture, Robert Kelley, 2003/05/31