-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 (9/28/06):
+FLEX pager towers are between 929 MHz and 932 MHz at 25 KHz centers.
-FLEX receiving is nearing completion.
+Current status (7/16/07):
-pager.slicer_fb() Accepts a complex baseband downconverted channel
- and outputs 4-level FSK symbols [0-3] as bytes.
- This may migrate into gnuradio-core at some point.
+FLEX receiving is completed except for addition of BCH error correction.
-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.
+There are three scripts:
-pager.flex_parse() Sink block that accepts a single phase of FLEX data
- words and unpacks and parses individual pages.
- Currently, this block decodes the capcodes of each
- receive page and displays the page type, but not yet
- the contents.
+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.
-pager.flex_decode() Combines the above blocks correctly to convert
- from downconverted baseband to pager messages
+ Usage: usrp_flex.py [options]
-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.
+ 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.
+
+ Usage: usrp_flex_all.py [options]
+
+ 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
+
+ Example, to receive all pager channels with DBSRX in side A:
+
+ $ usrp_flex_all.py -R A
+
+The demodulator is relatively sensitive to frequency offset and can capture a signal
+within 3k of the actual signal.
+
+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
projects / debian / gnuradio / blobdiff