baseband sample rate in ni usrp radios
each wireless testbench™ reference application object enables you to set the baseband sample rate of the
radio by using the samplerate
object property. the object automatically
selects the master clock rate on the radio hardware based on the specified sample rate. if
necessary, to achieve the specified sample rate, the radio uses a farrow rate
converter.
supported master clock rates
the analog-to-digital converter (adc) and digital-to-analog converter (dac) in usrp™ radios run at the full master clock rate, which is hardware-dependent. this table shows the master clocks rates available on supported ni™ usrp radios.
radio device | master clock rate |
---|---|
usrp n310 |
|
usrp n320 |
|
usrp n321 |
|
usrp x310 |
|
usrp x410 |
|
set baseband sample rate
the object automatically selects the master clock rate on the radio hardware based on
the samplerate
property value. if necessary, to achieve the specified
sample rate, the radio uses a farrow rate converter along with integer interpolation for
transmit signals or integer decimation for capture signals.
to bypass the farrow filter, set the samplerate
property to a
master clock rate value or to a value such that
mcr/samplerate
is a supported decimation or
interpolation factor, where mcr is the master clock rate that the object
selects.
radio | supported decimation or interpolation factor |
---|---|
usrp n310 usrp n320 usrp n321 usrp x410 | 1 |
2 | |
3 | |
even integer in the range from 4 to 256 | |
multiple of 4 in the range from 256 to 512 | |
multiple of 8 in the range from 512 to 1016 | |
usrp x310 | integer in the range from 1 to 128 |
even integer in the range from 128 to 256 | |
multiple of 4 in the range from 256 to 512 | |
multiple of 8 in the range from 512 to 1016 |
farrow rate converter
if mcr/samplerate
is not a supported decimation
or interpolation factor, the signal passes through the farrow rate converter. because of
hardware limitations, the farrow rate converter can only convert sample rates that are less
than mcr/2.
resampling transmit waveform
if the ,
,
or
object uses a farrow rate converter to achieve the sample rate specified by the
samplerate
property, the object resamples the transmit waveform that
you specify when calling the transmit
object function. the resulting
waveform has an increased number of data samples.
see also
objects
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