Re: [Discuss-gnuradio] I&Q on same or separate channels?

[Eric Blossom]

On Fri, Dec 14, 2007 at 02:17:19AM -0500, George Nychis wrote:
>
>>
>> I and Q are not on separate channels.  They are interleaved, I0, Q0, I1, 
>> Q1...
>>
>
> Are we sure of this?  Based on Brian's pointer to here:
> http://gnuradio.org/trac/browser/gnuradio/branches/features/inband-usb/usrp/fpga/toplevel/usrp_inband_usb/usrp_inband_usb.v#L235
>
> ... it seems as though they are wired to separate channels.  We then use 
> them as inputs to rx_buffer_input here:
> http://gnuradio.org/trac/browser/gnuradio/branches/features/inband-usb/usrp/fpga/toplevel/usrp_inband_usb/usrp_inband_usb.v#L260
>
> ... but only ever read from channel 0 (I).
>
> Is there a module we are missing that interleaves them?
>
> - George

Sorry George, I misunderstood which definition of "channel" you were
using.  Yes, in the legacy code they come from separate channels, but
those channels are paired and interleaved to define a "channel" as
seen by the host code.

Eric