From: "Deqiang chen" <address@hidden>
To: address@hidden
CC: address@hidden
Subject: RE: [Discuss-gnuradio] Re: FSK now (really) working at 100kbit/sec
Date: Fri, 15 Apr 2005 19:38:32 +0000
Thanks, guys!
Now I have another problem about how to use split the dat stream.
I would like to split a data stream, put it into parallel streams and show
these streams on
screen. Note that I would like to show these data streams together in a
single window.
Could any one give me a hint about how I could do that ?
I actually notice there is gr.serial_to_parallel, but the following code
block_size=1024
sp=gr.serial_to_parallel(gr.sizeof_float,block_size)
sink, win = scopesink.make_scope_sink_f (self, panel, "Rx Data",
input_rate)
vbox.Add (win, 1, wx.EXPAND)
self.connect (u,c2f_1)
self.connect( c2f_1, sp)
self.connect(sp,(sink,0))
produce an error , i.e.,
self.connect(sp,(sink,0))
File
"/usr/local/lib/python2.3/site-packages/gnuradio/gr/basic_flow_graph.py",
line 114, in connect
self._connect (points[i-1], points[i])
File
"/usr/local/lib/python2.3/site-packages/gnuradio/gr/basic_flow_graph.py",
line 119, in _connect
self._connect_prim (s, d)
File
"/usr/local/lib/python2.3/site-packages/gnuradio/gr/basic_flow_graph.py",
line 127, in _connect_prim
self._check_type_match (src_endpoint, dst_endpoint)
File
"/usr/local/lib/python2.3/site-packages/gnuradio/gr/basic_flow_graph.py",
line 238, in _check_type_match
raise ValueError, 'source and destination data sizes are different'
ValueError: source and destination data sizes are different
what is wrong with the code ?
Thanks!
david
From: Eric Blossom <address@hidden>
To: Deqiang chen <address@hidden>
CC: address@hidden
Subject: [Discuss-gnuradio] Re: FSK now (really) working at 100kbit/sec
Date: Fri, 15 Apr 2005 10:41:42 -0700
On Fri, Apr 15, 2005 at 03:37:27PM +0000, Deqiang chen wrote:
> hello, Eric,
>
> I remembered there is an annoucement that FSK can work at 100kbps.
> So I dig it out and take a look at the source code for the FSK (
> fsk_rx.py) . I am a little surprised
> that there are no time recovery there.
> My understanding is that for fsk, if you use noncoherent
> demodulation, you would not need the phase information. However,
> you still need to know the timing in order to correctly sampling the
> output of correlator or matched filter. Could you give a hint of
> what is going on here ?
> david
The output rate of gr.quadrature_demod_cf is 8 times the symbol rate.
The selection of the center of the bit is done in gr.simple_correlator.
It watches for a pseudo random sync pattern at the beginning of
each packet and uses this to figure out which of the possible alignments
is best. A similar technique is used in Bluetooth.
Eric
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