Hello,
I’m currently trying to port a radio design to the USRP2 platform but
I am having a few issues. The current radio hardware contains a DAC
with variable sampling rates allowing for it to be a multiple of the
bitrate. It is currently using an IF of 60Mhz and a bitrate of 6Mbps.
I’m wondering if there are any utilities the USRP2 provides for
designing radios where the sampling rate and bitrate are not
multiples, such as a DDS, given that the sampling rate is locked to
100MS/s. Thanks in advance.
Charles
On 12/29/2009 10:49 AM, Charles I. wrote:
Hello,
I’m currently trying to port a radio design to the USRP2 platform but
I am having a few issues. The current radio hardware contains a DAC
with variable sampling rates allowing for it to be a multiple of the
bitrate. It is currently using an IF of 60Mhz and a bitrate of 6Mbps.
I’m wondering if there are any utilities the USRP2 provides for
designing radios where the sampling rate and bitrate are not
multiples, such as a DDS, given that the sampling rate is locked to
100MS/s. Thanks in advance.
We do have all sorts of DDS modules in the FPGA and in software, but
that will only change the center frequency, not sample rate.
There are many resampling options in GNU Radio. There are polyphase
resamplers, rational resamplers, arbitrary resamplers, etc. There is
also timing recovery.
While it is often convenient to have a hardware sample rate which is an
integer number of symbols on the transmit side, you will usually still
need to resample on the receive side for timing recovery.
Matt