myhanguk
Guest
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 Posted:
Wed Nov 30, 2005 5:17 pm Post subject:
How to understand Digital IF... |
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Hi...
Hope this message finds you all in good health.
I am not a DSP engineer, but have to process IQ data from channe
measurements.
The new data I received, has been converted from Digital IF to baseband.
Downconversion has been performed using digital cos and si
implementations such that it corresponds to simple multiplications by [1
-1 0] for digital cos and [0 1 0 -1] for digital sin.
The resulting (I,Q) sequence looks as follows:
(X,0)
(0,X)
(X,0)
(0,X)
How do I interpret this data ? This data is supposed to represent 4
oversampled data, but it seems the information content is only 2
oversampling due to all the zeros...
Is this situation solved if I apply the lowpass filter (in our case, a
RRC filter)?
If somebody can help me understand this probably trivial issue, pleas
don't hesitate to confront me with my own ignorance...
Thanks a lot...
Park KH |
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Guest
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| Posted:
Thu Dec 01, 2005 9:16 am Post subject:
Re: How to understand Digital IF... |
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myhanguk wrote:
| Quote: | Hi...
Hope this message finds you all in good health.
I am not a DSP engineer, but have to process IQ data from channel
measurements.
The new data I received, has been converted from Digital IF to baseband.
Downconversion has been performed using digital cos and sin
implementations such that it corresponds to simple multiplications by [1 0
-1 0] for digital cos and [0 1 0 -1] for digital sin.
The resulting (I,Q) sequence looks as follows:
(X,0)
(0,X)
(X,0)
(0,X)
How do I interpret this data ? This data is supposed to represent 4x
oversampled data, but it seems the information content is only 2x
oversampling due to all the zeros...
Is this situation solved if I apply the lowpass filter (in our case, an
RRC filter)?
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Yes.
Regards,
Allan |
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