A Gnu Radio flow-graph for producing raw filterbank files from a live SDR
It produces 16-bit or 8-bit binary outputs, arranged from lowest to highest frequency in the filterbank output.
The code automatically determines suitable filterbank sizes and output rates. A header file is produced that gives the calculated rates, etc. The output file is in .FIL format, so it includes header information that makes it useful for downstream tools like the PRESTO toolsuite.
Also, a shell script, observe_pulsar can be used to manage an observtion with this Gnu Radio app.
Currently supported options:
Usage: pulsar_filterbank.py: [options]
Options:
-h, --help show this help message and exit
--bbgain=BBGAIN Set Baseband Gain [default=10.0]
--dec=DEC Set Source DEC [default=54.5]
--device=DEVICE Set Hardware device string [default=airspy=0]
--dm=DM Set Dispersion Measure [default=28.3]
--dscale=DSCALE Set Detector scaling [default=1]
--freq=FREQ Set Tuner Frequency [default=612.0M]
--hp=HP Set HP pass enable [default=1]
--hpgain=HPGAIN Set High Pass pseudo-gain [default=600.0m]
--ifgain=IFGAIN Set IF Gain [default=10.0]
--pps=PPS Set PPS source [default=internal]
--prefix=PREFIX Set File prefix [default=./]
--pw50=PW50 Set Pulsar PW50 [default=6.6m]
--ra=RA Set Source RA [default=3.51]
--refclock=REFCLOCK Set Reference Clock Source [default=internal]
--resolution=RESOLUTION
Set FB resolution multiplier [default=1]
--rfgain=RFGAIN Set RF Gain [default=15.0]
--rfilist=RFILIST Set RFI frequency list [default=]
--rolloff=ROLLOFF Set Enable Roll-off correction [default=1]
--runtime=RUNTIME Set Total runtime (seconds) [default=600]
--source=SOURCE Set Source Name [default=B0329+54]
--srate=SRATE Set Hardware Sample Rate [default=5.0M]
--subdev=SUBDEV Set Subdev spec, UHD-version only [default=A:0]
--thresh=THRESH Set RFI detection threshold--linear factor
[default=2.5]
--wide=WIDE Set Enable 16-bit output [default=0]
--sky=SKY Set independent SKY frequency. [default=0]
--integrator=INTEG Use integrate-and-dump instead of IIR filter [default=0]
The 'observe_pulsar' script makes some of this easier to deal with:
Usage: observe_pulsar :
--name Pulsar name. Default: B0329+54
--freq Center frequency **IN MHz**. Default: 408.0
--srate Sample rate, **IN MHz**: Default: 4.0
--rfgain RF gain, usually in dB. Default: 40
--longitude Local longitude. Negative is west.: Default: -76.03
--dscale Detector scaling: Default: 1
--wide Enable Wide (16 bit) samples Default: 0
--hp Enable high-pass filter. Default: 0
--hpgain Set "gain" on high-pass. Default: 0.6
--obstime Observing time, **MINuTES**. Default: 5
NOTE: A negative 'obstime' results in running immediately
rather than waiting for the object to enter the FOV.
--prefix Output file prefix. Default: ~
--rolloff Enable roll-off correction
--sky Set sky frequency
--integrator Turn on integrator instead of IIR filter
Appropriate pulsar parameters will be taken from a database of about 200 objects, included in this source package.