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Diffstat (limited to 'gr-pager/README')
| -rw-r--r-- | gr-pager/README | 100 |
1 files changed, 74 insertions, 26 deletions
diff --git a/gr-pager/README b/gr-pager/README index 4327f258e..2d4f3c95c 100644 --- a/gr-pager/README +++ b/gr-pager/README @@ -1,37 +1,85 @@ -This GNU Radio component implements (will implement) common radiopager -signaling protocols such as POCSAG and FLEX. +This GNU Radio component implements a FLEX radiopager receiver/demodulator. -Current status (10/6/06): +FLEX pager towers are between 929 MHz and 932 MHz at 25 KHz centers. + +Current status (7/16/07): FLEX receiving is completed except for addition of BCH error correction. -pager.slicer_fb() Accepts a complex baseband downconverted channel - and outputs 4-level FSK symbols [0-3] as bytes. +There are three scripts: + +usrp_flex.py - Receives and displays pages from a single paging channel. To + work from recorded data, record from USRP with decimation 256 + at center frequency. + + Usage: usrp_flex.py [options] + + Options: + -h, --help show this help message and exit + -f Hz, --frequency=Hz set receive frequency to Hz + -R SUBDEV, --rx-subdev-spec=SUBDEV select USRP Rx side A or B + -c Hz, --calibration=Hz set frequency offset to Hz + -g dB, --gain=dB set RF gain + -l, --log log flowgraph to files (LOTS of data) + -v, --verbose display debug output + -F FROM_FILE, --from-file=FROM_FILE read samples from file instead of USRP + + Example, to receive from 931.95M (a common nationwide channel) with DBSRX in + side A of USRP: + + $ usrp_flex.py -f 931.95M -g 32 -R A + + +usrp_flex_band.py - Receives and displays pages from a 1 MHz paging band (40 pager + channels.) To work from recorded data, record from USRP with + decimation 64 at center frequency. + +Usage: usrp_flex_band.py [options] + + Options: + -h, --help show this help message and exit + -f Hz, --frequency=Hz set receive center frequency to Hz + -R SUBDEV, --rx-subdev-spec=SUBDEV select USRP Rx side A or B + -c Hz, --calibration=Hz set frequency offset to Hz + -g dB, --gain=dB set RF gain + -F FROM_FILE, --from-file=FROM_FILE Read from file instead of USRP + -l, --log log flowgraph to files (LOTS of data) + -v, --verbose display debug output + + Example, to receive from the lower third of the pager band with DBSRX in side B + of USRP: + + $ usrp_flex_band.py -f 929.5M -g 32 -R B + +usrp_flex_all.py - Receives and displays pages from entire pager band (3 MHz, + 120 pager channels.) This does not work in real time due + to CPU limitations, but can work from recorded USRP data. To + work from recorded data, record from USRP with decimation 20 at + center frequency of 930.5M. -pager.flex_sync() Accepts 4FSK symbol stream at channel rate and - outputs four phases of FLEX data bits as bytes. - Auto-shifts to 3200 bps as determined by received - FLEX synchronization word. - -pager.flex_deinterleave() Accepts a single phase of FLEX data bits and performs - deinterleaving on 256-bit blocks. Resulting code - words are error corrected using BCH 32,21 ecc (stub) - and converted into FLEX data words for output. + Usage: usrp_flex_all.py [options] -pager.flex_parse() Sink block that accepts a single phase of FLEX data - words and unpacks and parses individual pages. These are - passed outside the data plane via gr_message's. + Options: + -h, --help show this help message and exit + -R SUBDEV, --rx-subdev-spec=SUBDEVC select USRP Rx side A or B + -c Hz, --calibration=Hz set frequency offset to Hz + -g dB, --gain=dB set RF gain + -F FROM_FILE, --from-file=FROM_FILE Read from file instead of USRP + -l, --log log flowgraph to files (LOTS of data) + -v, --verbose display debug output -pager.flex_decode() Combines the above blocks correctly to convert - from downconverted baseband to pager messages + Example, to receive all pager channels with DBSRX in side A: + + $ usrp_flex_all.py -R A -usrp_flex.py Instantiates USRP receive chain to receive FLEX - protocol pages. See command-line help for options. - Right now this installs into $PREFIX/bin but will - probably make it into gnuradio-examples. +The demodulator is relatively sensitive to frequency offset and can capture a signal +within 3k of the actual signal. -aypabtu.py Decodes FLEX pages from multiple rx channels in a range. - Incomplete. +All three scripts take a 'calibration' parameter, which specifies the frequency offset +of the daughterboard. This causes the USRP to be tuned to the given center frequency +plus the calibration offset. For example, if your DBSRX shows 930MHz as 930.001MHz in +usrp_fft.py, then use '-c 1k' in the command line to automatically add this. Johnathan Corgan -jcorgan@aeinet.com +Corgan Enterprises LLC +jcorgan@corganenterprises.com |