1 This GNU Radio component implements a FLEX radiopager receiver/demodulator.
3 FLEX pager towers are between 929 MHz and 932 MHz at 25 KHz centers.
5 Current status (7/16/07):
7 FLEX receiving is completed except for addition of BCH error correction.
9 There are three scripts:
11 usrp_flex.py - Receives and displays pages from a single paging channel. To
12 work from recorded data, record from USRP with decimation 256
15 Usage: usrp_flex.py [options]
18 -h, --help show this help message and exit
19 -f Hz, --frequency=Hz set receive frequency to Hz
20 -R SUBDEV, --rx-subdev-spec=SUBDEV select USRP Rx side A or B
21 -c Hz, --calibration=Hz set frequency offset to Hz
22 -g dB, --gain=dB set RF gain
23 -l, --log log flowgraph to files (LOTS of data)
24 -v, --verbose display debug output
25 -F FROM_FILE, --from-file=FROM_FILE read samples from file instead of USRP
27 Example, to receive from 931.95M (a common nationwide channel) with DBSRX in
30 $ usrp_flex.py -f 931.95M -g 32 -R A
33 usrp_flex_band.py - Receives and displays pages from a 1 MHz paging band (40 pager
34 channels.) To work from recorded data, record from USRP with
35 decimation 64 at center frequency.
37 Usage: usrp_flex_band.py [options]
40 -h, --help show this help message and exit
41 -f Hz, --frequency=Hz set receive center frequency to Hz
42 -R SUBDEV, --rx-subdev-spec=SUBDEV select USRP Rx side A or B
43 -c Hz, --calibration=Hz set frequency offset to Hz
44 -g dB, --gain=dB set RF gain
45 -F FROM_FILE, --from-file=FROM_FILE Read from file instead of USRP
46 -l, --log log flowgraph to files (LOTS of data)
47 -v, --verbose display debug output
49 Example, to receive from the lower third of the pager band with DBSRX in side B
52 $ usrp_flex_band.py -f 929.5M -g 32 -R B
54 usrp_flex_all.py - Receives and displays pages from entire pager band (3 MHz,
55 120 pager channels.) This does not work in real time due
56 to CPU limitations, but can work from recorded USRP data. To
57 work from recorded data, record from USRP with decimation 20 at
58 center frequency of 930.5M.
60 Usage: usrp_flex_all.py [options]
63 -h, --help show this help message and exit
64 -R SUBDEV, --rx-subdev-spec=SUBDEVC select USRP Rx side A or B
65 -c Hz, --calibration=Hz set frequency offset to Hz
66 -g dB, --gain=dB set RF gain
67 -F FROM_FILE, --from-file=FROM_FILE Read from file instead of USRP
68 -l, --log log flowgraph to files (LOTS of data)
69 -v, --verbose display debug output
71 Example, to receive all pager channels with DBSRX in side A:
73 $ usrp_flex_all.py -R A
75 The demodulator is relatively sensitive to frequency offset and can capture a signal
76 within 3k of the actual signal.
78 All three scripts take a 'calibration' parameter, which specifies the frequency offset
79 of the daughterboard. This causes the USRP to be tuned to the given center frequency
80 plus the calibration offset. For example, if your DBSRX shows 930MHz as 930.001MHz in
81 usrp_fft.py, then use '-c 1k' in the command line to automatically add this.
84 Corgan Enterprises LLC
85 jcorgan@corganenterprises.com