-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 (9/13/06):
+FLEX pager towers are between 929 MHz and 932 MHz at 25 KHz centers.
-FLEX receiving is in mid-stream of implemention.
+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_deframer() Accepts a symbol stream from slicer_fb() and
- outputs received 32-bit FLEX codewords for each
- defined phase. Auto adjusts for 1600 or 3200 bps,
- and 2 or 4 level FSK encoding based on received
- synchronization word. The sync portion of this
- block may factor out into its own block for
- purposes of clarity and code complexity.
+There are three scripts:
-pager.bch3221_ecd() (not yet implemented) Accepts a stream of 32-bit
- FLEX codewords and applies BCH (32,21) error
- detection/correction (up to 2 bits), the emits
- corrected stream. This may be absorbed into the
- deframer at some point.
+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.message_decode() (not yet implemented) Accepts a stream of 32-bit
- FLEX codewords and separates individual paging
- messages into output stream as bytes.
+ Usage: usrp_flex.py [options]
-pager.flex_decode() Combines the above blocks correctly to convert
- from downconverted baseband to pager messages
+ 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
-usrp_flex.py Instantiates USRP receive chain to receive FLEX
- protocol pages. See command-line help for options.
- This will probably make it into gnuradio-examples.
+ 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