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Re: [Discuss-gnuradio] AD9862 Functionality
From: |
Brian Padalino |
Subject: |
Re: [Discuss-gnuradio] AD9862 Functionality |
Date: |
Tue, 20 Feb 2007 17:36:13 -0500 |
Eric,
Thanks for all the answers so far. I am really getting a grasp of
everything going on within the USRP. I really appreciate it.
On 2/20/07, Eric Blossom <address@hidden> wrote:
The code in usrp_standard.cc controls the FPGA interpolation rate.
The rates do not have to be powers of two. From the user point of
view the net interpolation rate must be in [4, 512] and a multiple of 4.
This is all controlled in usrp_standard.cc. I suggest that you take a
look at it ;)
I have been perusing it, and I will definitely take a closer look. Thanks!!
> Or is a modulator block required to do things in powers of 2 when
> connected to a USRP?
No. You might want to start looking at for example, the gmsk
modulator/demod: gnuradio-core/src/python/gnuradio/blksimpl/gmsk.py
I suppose I should clarify the rates. All bandwidths have to be some
decimation from 64Msps that is also divisible by 4. For example, I
could not choose to run a bandwidth of 1.2MHz through the USRP.
Is there an inherent sample frequency of 8Msps when dealing with the
USRP? It seems with 16-bit complex data, the USB is able to transfer
8Msps. If I set the GMSK modulator to have 20 samples per symbol,
will that give me an effective bandwidth of 400kHz?
Thanks,
Brian